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, :~... ,.- AMERICAN HORTICULTURAL SOCIETY A union of the Ame1'ican H 01· ticultuml Society and the American H 01·ticultuml Council 1600 BLADENSBURG ROAD, NORTHEAST. WASHINGTON 2, D. C.

For United Horticulture *** to accumulate, increase, and disseminate horticultural information

B. Y. MORRISON, Editor Directors T erms Expiring 1960 JAMES R . HARLOW, Managing Editor DONOVA N S. CORRELL Texas CARL W. FENNINGER Editorial Committee Pennsylvania W . H . HODGE, Chairman W . H. HODGE Pennsylvania JOHN L. CREECH A. J . IRVI NG FREDERIC P. L EE New York WILLIAM C. STEERE CONRAD B . LINK New York CURTIS MAY T erms Expiring 1961 FREDERICK G . MEYER STUART M. A RMSTRONG WILBUR H . YOUNGMAN Ma'ryland JOH N L. C REECH Maryland "VILLIAM H . FREDERICK, JR. Officers Delaware FRANCIS PATTESON-KNIGHT PRESIDENT Virginia RICHARD P. WHITE Washington, D. C. DONALD WYMAN 1'.1 assachusetts FIRST VICE-PRESIDENT T erms Expi1'ing 1962 DONALD ,.yYMAN Ja maica Plain, Massachusetts FREDERIC P . LEE Ma'ryiand H ENRY T . SKINNER SECOND VICE· PRESIDENT District of Columbia STUART M. ARMSTRONG GEORGE H . S PALDING Silver Spring, Maryland Califomia RICHARD P . WHITE SECRETARY-TREASURER Dist'rict of Columbia OLIVE E. WEATHERELL ANNE WERTSNER WOOD Washington, D. C. Pennsylvania

The American H orticultural Magazine is the official publica tion of the American Horticultural Society and is issu ed four times a year during the quarters commencing with January, April, July and October. It is devoted to the dissemination of knowledge in the science and art of growing ornamental plants, fruits, vegetables, and related subjects. Original papers increasing the historical, varietal, and cultural knowledges of plant materials of economic and aesthetic importance are welcomed and will be published as early as possible. The Chairman of the Editorial Committee should be consulted for manuscript specifications. R eprints, saddle-stapled, will be furnished in accordance with the following schedule of prices, plus postage, and should be ordered at the time the galley proof is returned by the author: One hundred copies-2 pp $6.60; 4 pp $12.10; 11 pp $25.30; 12 pp $36.30; Covers $12.10.

Entered as second class matter in the post offi ce at Baltimore, Maryland, in accordance with the Act of August 24, 1912 . Additional entry for Was hington, D .C., was authorized July IS, 1955, in accorda nce with the pro­ visions of Section 132.122, Postal Ma nua l. A subsc ription to The A merican H OTl iculi ural Magazine is included as a benefit of membership in the Ameri can Horticultural Society, Individual Membership dues being $6.00 a year. JULY. 1960

FORMERLY THE NATIONAL HORTICULTURAL MAGAZINE VOLUME 39 • NUMBER 3

Contents

Nature of Plant Sports. HAIG DERMEN .______123

Forty illustrations from photo­ graphs furnished by the author

Introduction by GEORGE M. DARROW

A Book or Two ______.______174

The Gardeners' Pocketbook

M eriania nobilis. W. H. HODGL ______. ______. 177

A Technique for Growing Azaleas in Bermuda. JOHN KN 0 '~I L TO N______179

Two Experiences with Tree Peony Propagation. MAUD R. J ACOBS .______181

S.outhern Viburnums. E. J. HORDER ______.. ______182

SpathicaTpa sagittifoLia. D. G. HUTTLESTON ______183

New Guinea Trumpet-Creeper. "". H. HODGL ______184

JULY COVER ILLUSTRATION (G. HAMPFLER)

A floweloing plant of StJathicarpa sagittifolia as grown under cultivation at Longwood Gardens, Kennett Square, Pennsylvania. The caterpillar plant is native to Brazil. ... See details on Page 183

Copyright 1960 by T he American Horticultural Society, Inc. c. HAMPFLER

T ecomanthe venusta

First {towering plamt in the liVestem Hemisphe?'e of the New Guinea Trumpet-CreepeL

[See Page 184]

11 Nature of Plant Sports

HAIG DERMEN Cytologist. U. S. Department of Agriculture. Agri· cultural ReseaFch Service, Crops Research Divi:-;ion. Beltsville. Maryland.

I. Introduction

GEORGE M. DARROW Formerly Principal Horticulturist at U.S.D.A.

This article might have been entitled "A Key to the NIystery of Plant Sports" since it unravels so precisely the nature of variations or sporting in many plants that have puzzled horticulturists, plant breeders and plant hobbyists in general. The discussion on the NatuTe of Plant SP01·tS by Dr. Dermen summarizes a part of his work in one field of botany in which h e has been interested for much of the past twenty years. Dr. Dermen came to the fruit research group of the U. S. Department of Agriculture from Bussey Institution of Harvard University in 1937 to study cytological problems of fruits. He soon became the world authority on the cytogenetics of fruits and on the use of colchicine in obtaining polyploids or cytological sports. In most cases the polyploid plants proved to be chimeral with only certain tissues being tetraploid, the rest being diploid. In the following pages he tells clearly and simply 'what plant sports are. It will be a stimulating experience to the reader. By following his description and discussion, it is possible for a horticulturist to understand what a plant sport is and what to expect of a plant sport. The discussion is basic to the propagator of vegetative sports, such as color sports of apple, early and late maturing sports of peach, or thornless blackberry, as well as to the breeder who wishes to use a poly­ ploid plant in breeding, to the horticulturist who is curious about variegations and all sorts of chimeral forms, and to the teachers of botany and horticulture who are illterested in the problems of specific origin of tissues in plants. This ar­ ticle also may be of particular interest to radiologists who attempt to induce mutations in plants, and to virologists who would be interested in the diagnosis of some plant defects whether they are symptoms of virus effect or are expres­ sions of genetic vegetative mutations. Although the approach of the article is toward an understanding of basic facts and the article itself may seem forbidding to non-professional botanists, this must not mislead the reader since Dr. Dermen has really made conscious effort to make all the essential facts as simple and clear as possible or practicable. How­ ever, this is not like a story to be read hurriedly. It will be slow reading for most people who wish a thorough understanding of the subject. Cytological chimeras-termed cytochimeras-obtained from colchicine-treated peaches and naturally-occurring sports of apples are illustrated and explained. An understanding of these makes it possible to understand naturally-occurring vege­ tative sports such as color sports of fruits and leaf variegations. Many points of a basic nature in the article have not been reported previously. [123] 124 THE AMERICA HORTICULTURAL IVIAGAZINE

Fig. 1. A variegated poinsettia leaf and a peach-nectal-ine fruit.

II. The Anatomy and Cytology of Chimeras

The appearance of vegetative sports few of them, such as leaf variegation and and their behavior have puzzled and in­ fruit sports (Fig. 1) . It will also explain trigued plantsmen and investigators for why some sports are fixed, and why and generations. The appearance of a fuzz­ how others revert to their original forms. less peach or of a peach with patches of For example, when we examine varie­ white and yellow flesh, or the develop­ gated leaves of plants, such as privet, ment of branches with variegated leaves English ivy, or geranium, we will see that on a privet or holly plant is an example the pattern of the contrasting colors is of a phenomenon recurring through the never exactly the same in any two leaves. centuries that man has cultivated plants. In extreme instances, some leaves would Explanations in the literature on the appear to have reverted to the original subject of vegetative sports have not been green color and others would have be­ fully adequate. A more precise explan­ come completely colorless or may have ation of sporting as described in this ar­ taken entirely the sporting color. Simi­ ticle has been possible only in recent larly, on a tree of a red fruited sport of years (6). * Studies of diploid (sum of apple, a branch may be found with fruits chromosomes of two sex cells. called with less color that resemble those of the gametes) , and polyploid (a multiple of original variety, while the fruits on the the number of chromosomes of diploid) rest of the tree have the intense coloring, chimeras (6, 26) in plants resulting from characteristic of the sport variety. This the use of the drug colchicine have given phenomenon is called reversion of sport us a better understanding of the nature to normal, an undesirable phenomenon, of vegetative sports. horticulturally speaking. As we shall see, the story of sports is li' • The present article has been prepared to help readers of this Magazine under­ closely tied to the development of the stand the nature of common sports by gmwing point of the shoot. The gro:w­ describing the origin and make-up of a ing point is also called the shoot tIP, shoot apex, apical meristem, or apical · See N umerica l References on Page 172. dome. Therefore, a close study of this JULY 1960, VOLUME 39, NUMBER 3 125

region of plants is very pertinent. '!\Then the part of the twig from which stem tis­ a prepared microscopic section of a bud sues develop. ·When a plant is actively or shoot tip is examined under a high­ growing, the cells at the tip divide fre­ power microscope, we see at the tip a quently, the shoot tip continuously broad, usually curved area that grows grows outward, and leaves are initiated rapidly from which new leaves, stem, along its margin. A shoot tip, instead of flower, and fruit develop. Figure 2 shows growing into a twig with leaves, may a highly magnified section through a also develop into a flower. shoot tip of peach with the growing Generally speaking, vegetative plant point indicated by an arrow. Masses of sports are more or less permanent cells above and along the sides of the changes or variations from normal. They growing point represent sections of are brought about principally by a ge­ leaves and leaf stipules, while the mass netic change (mutation, sporting) in one of tissue just under the growing point is or more genes or by chromosomal

Fig. 2. A microscopic longitudinal section through a peach shoot tip. (Apical dome of shoot tip indicated by arrow.) 126 THE AMERICAN HORTICULTURAL MAGAZINE changes occurring originally in the nu· trations represent the very tip of a shoot, cleus of a single cell at the very center the same apical dome region as indicated of a growing point of a bud or shoot. in Fig. 2, but at a higher magnification. Some sports are also known to have oc­ As the cells divide and the shoot grows cUlred from a mutation outside of the forward, small bulges occur at the sides nucleus of a cell, in the cytoplasm. The of the apical dome at definite intervals. first group of sports are of nuclear ori­ One such bulge is seen at the right side gin and those in the second gr'oup are of the dome in Fig. 3-C. Such bulges of cytoplasmic origin. grow into leaves, and are the very begin­ Many mutations can be recognized ning of leaf formation. when gTowing points have given rise to Since development of plant parts is leaves, flowers, or fruits. Other mutations initiated at the growing point of a bud affect the physiology of the plant and or twig, chromosome doubling follow­ may not be so easily recognized. As ing colchicine treatments was looked for stated above, details of this phenomenon in the tip region of shoots. The tips in have become clearly evident only in re­ Fig. 3 represent six different types of cent years as a result of experiments in partial polyploidy resulting from two polyploidy (doubling of chromosomes), different chromosome numbers in shoot induced by use of the chemical colchi· tips. Significan t features of these tips cine to produce new varieties of plants. are: 1) cells are normally arranged This induced polyploidy, termed co lchi­ pretty much in layers, and 2), if col chi­ ploidy, often may result in giant forms ploidy is induced, it is usually limited of flowers and fruits, or it may change initially to one of the layers in the shoot sterile species hybrids into fertile forms. apex. Thus, as a result of colchiploidy, The pol yploidizing effect of colchicine we find the dual chromosome condition occurs in rapidly dividing cells. There­ in a shoot apex to be precisely delimited. fore, colchicine is applied to buds of The teTm chimem is given to such du­ actively growing plants. The polyploidal ality whetheT it Tep1-esents a diffeTence effect of colchicine is observed first in in chmmosome numbeT, as in the six the leaves developing from a treated bud gTowing points shown in Fir;. 3, 01' sim­ and later in flowers and fruits (5, 14, ply a diffeTence in genes in diffeTent lay­ 20). ers of cells, expTessed in coloT 01' otheT­ Cytochimems in peach. - In experi­ wise. The condition of duality in ments performed at the Plant Industry chromosome number is termed cytochi­ Station, Beltsville, Maryland, first with mem (cyto-from cytology, the science cranberry plants (19) and later with of cells) or peTiclinal (parallel with the peach (13) to induce doubling of circumference, for example, of a stem) - chromosome numbers, it became evident cytochimem. Duality in color of leaves that only rarely did chromosome dou­ due to gene mutation or cytoplasmic mu­ bling take place in all tissues in the new tation is termed vaTiegation. growth from a treated bud. Instead, we In the shoot apex the arrangement of usually obtained chimeu{s. It meant cells in distinct layers is due to division that in some tissues of these plants the of cells in the upper portion of the dome chromosome number had doubled once, in a vertical plane, that is at right angles becoming tetmploid (double of dip­ to the surface of the dome. Why the loid); in other tissues, where no change cells in the upper region of the dome had taken place, they rennined diploid. divide predominantly in this manner is The resulting plant (part tetraploid, still unsolved. The cells located under­ part diploid) is known as a peTiclinial neath the outer few rows divide in more chimem. In order to understand this haphazard fashion - vertically, horizon­ phenomenon, detailed microscopic ex­ tally, or diagonally, with respect to the aminations were made of growing surface. Consequently, twig growth is points, leaves, stem, flowers, and fruits both in length and in width. of both normal and chimeral materials The upper illustrations in Fig. 3 show at their early stages of growth (7, 11, 12, four different chimeral shoot tips of 13, 14, 18) . peach. Each represents a differen t kind Figure 3 shows longitudinal sections of chromosomal-periclinal-chimera com· through shoot tips of six peach twigs. posed of diploid and tetraploid regions The broad curved portion in these illus- resulting from colchicine tre'Hment. JULY 1960, VOLUME 39, NUMBER 3 12'1

Fig. 3. Microscopic longitudinal sections of six shoot tips of peaches) indicating variously diploid-tetmploid chimeras. 128 THE AMERICAN HORTICULTURAL MAGAZINE

The lower two illustrations in Fig. 3 these two domes, the layers of cells above show tips of two twigs developed later­ the ink line are diploid and the tissues allv on a shoot the dome of which is beneath are tetraploid. As a tree with ill~strated in Fig~ 3-B. These photomicro­ the chimera I condition shown in Fig. graphic sections are magnified abo~t four 3-B grows and expands, some twigs will hundred times. They were exammed at have this arrangement; a very few will much higher magnification, however, in be of the type shown in Figs. 3-E and order to establish whether cells in cer­ 3-F; but some will be entirely diploid. tain regions were diploid or tetraploid. Thus, a chimera of the type 2-2-4 (dip­ This cytological difference was deter­ loid-diploid-tetraploid) may become 2- mined mostly from the size of nuclei, 2-2 (diploid in all three layers) and a but in part from differences in cell size chimera of type 2-4-2 may change to and the chromosome number in cells in 2-4-4. Very rarely 2-4-4 type will change which chromosome number could be de­ to 2-2-4 or 2-2-2. In one instance, an termined or estimated (for more detail, entirely diploid branch was found on a see references 12, 18). As the diploidy 2-4-4 chimeral peach tree. and tetraploidy of regions were deter­ Study of chromosomal chimeras has mined under the microscope, an ink been very useful. It has made it possible line was drawn between differing regions to learn the exact origin of tissues and on the photographic prin ts. This was tissue system or areas within leaves, done so that different chromosomal re­ stems, flowers, and fruits, and the rela­ gions could be identified at a glance. tionship of each tissue, or tissue area in­ Close observation of Fig. 3-A shows side each plant organ, or plant part, to that the cells above the ink line are a particular apical layer. Since all these small and that the nuclei in cells of the plant organs or parts develop from the single row desig-nated L-I are small com­ shoot apex, and are actually and directly pared with those in layers of cells L-ll transformations or differentiations of and L-llI. Thus L-I was determined to shoot or bud tips, it should be readily be diploid and L-II, L-llI, and deeper possible to trace the origin of any tissue tissue were tetraploid. L-l, L-lI, and or internal area in a plant organ back L-llI are terms applied to layers of cells to a specific apical layer. A root is also in all growing points described in this a plant part but it is not considered article. Fig. 3-B shows a dome in which here. (See page 167). the upper layers, L-l and L-ll, are dip­ Microscopic sections of very young loid and the rest of the tissue in the leaves of a vigorously growing peach dome is tetraploid. In Fig. 3-C, L-ll­ twig are shown in Fig. 4. Fig. 4-A shows between the two ink lines-is tetraploid sections cut through young leaves (a, b, and L-I, L-llI and the tissue deeper in c, and d) at a level considerably above the dome are diploid. Fig. 3-D shows the the dome area of a twig. Fig. 4-B shows reverse of the type illustrated in Fig-. a section through the same twig but at 3-C. Here L-ll is diploid and L-l, L-llI a point very close to the dome. Here are and the inner tissues are tetraploid. The shown sections of two additional leaves, chromosome number (ploidy) of all in­ e and f. Leaf a is the oldest and f the ner tissues was usually found to be the youngest and the others are lettered in same as that of the third layer, L-llI. that order. The twig was from a plant No type of chimeral condition in the that had the 4-2-4 chimeral makeup. De­ plants studied vvas strictly permanent. termination of different ploidy in each The most stable chimeral condition was tissue of the leaves in these sections the type in which L-I differed from the showed that only the epidermal tissue inner tissues. It is obviously due to the of the leaves originated from L-I; the fact that the plane of cell division be­ entire internal tissue of the leaf blade comes increasingly random in cells lo­ originated from L-II; and only the bulk cated farther away from the surface of of the midrib tissue originated from the dome, as indicated previously, L-llI. In the lower portion of leaf a, whereas the plane of cell division in L-I the 4x (tetraploid) epidermis is par­ is varied seldom. As mentioned above, tially delimited with an ink line (shown the two domes shown in Figs. 3-E and by an arrow) and an island of 4x tissue 3-F are from lateral twigs of a shoot, the in the midrib region of each leaf is also dome of which is shown in Fig. 3-B. In delimited with an ink line. JULY 1960, VOLUME 39, NUMBER 3 129

Fig. 4. Two CTOSS sections of 4-2-4 chimeral peach shoot at a little distance above the apical dome region to show details as to origin of tissues in leaves from apical layers L-I) L-II) and L-III. 130 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. 5. Tmnsven e sections of two twigs. Top, back of dome in Fig. 3-E. Bottom, back of dome in Fig. 3-F.

Figure 5 shows cross sections of twigs from L-I as in leaves; L-ll gave rise to cut a little distance back of the domes part of the cortical tissue under the epi­ shown respectively in Figs. 3-E and 3-F. dermis to varying depths, sometimes The tissue enclosed by the wavy ink line even extending beyond cortical tissue in both sections is 4x. This illustrates deep into the vascular tissue system how irregular may be the patterns of 2x (the darkly stained band of tissue in the and 4x tissues in the stem. A study of stem sections) and into the pith tissue stem (twig) sections of 2-4-2 and 4-2-4 in the center of the stem. L-llI usually chimeral-type plants showed that the gave rise to the inner part of the corti­ epidermal tissue of the stem originated cal tissue, conductive tissue and pith. JULY 1960, VOLUME 39, NUMBER 3 131

Fig. 6. A section tht-ough an embryonic fTuit of a 2-2-4 chimeral peach befoTe opening of {loweT.

Figure 6 shows a section through an The black ink line indicates the boun­ embryonic fruit taken from inside of a dary between 2x and 4x regions, a very flower bud. It was from a tree of 2-2-4 wavy path at the outer portion of the chimeral type, the dome of which is fruit and a more or less straight line shown in Fig. 3-B . The white line in (not so visible because of darkly stained the fruit section was drawn to show the tissue in the region) by the seed cavity. approximate boundary line of the pit. The tissue enclosed by the black line The tissue outside the white line grows was 4x, and that of other parts 2x. into the fleshy part of the mature fruit At the very beginning of fruit devel­ and that inside into the hard pit tissue. opment in the flower bud of peach and ]32 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. 7. Sections through suture area of three peach fruits. A, a diploid fruit,' Band C, fruits of a 4-2-2 type chimera.

related stone fruits, the fruit looks some­ Cytochimems in apple.-Studies sim­ what U-shaped when viewed from the ilar to those in peach were made with top or in a transverse section with the a chimeral apple 'w hich had occurred aid of a microscope, and changes with naturally. Chimeral conditions in these growth into a closed form like an "0." two plants were alike in certain res pects Therefore, when the two edges of the but they also had certain important dif­ primordial fruit eventually meet, they ferences. Fig. 8-A illustrates a shoot apex fuse and form a deep line in stone fruits of the 2-4-2 type chimera in apple which known as the su ture. A slight dip in the is similar to tha t shown for peach in upper part of the fruit section in Fig. 6 Fig. 3-C. Some other apples studied were represents the suture. When the suture of 2-4-4 and 2-2-4 types. Fig. 8-B shows area of fruits of plants with 4-2-2 and a transverse section of the twig a little 2-4-4 chimeras was studied microscopi­ distance back of the dome shown in Fig. cally, it was found that only occasionally 8-A. In this stem section the central had two layers of cells originated from h omogeneous appearing tissue is the L-I in the suture; usu ally six or more pith. Around the pith the darkly layers of cells at the suture were of L-I stained band of tissue is the conductive origin. In Fig. 7-A is shown the suture tissue at the early stage of twig growth. area of a fruit from a plant in which Ou tside of this is the cortical tissue, and both L-I and L-II were 2x, therefore the outside of the cortical tissue is a thin whole tissue in the area of the suture is layer of cells, the epidermis. At the up­ 2x as in Fig. 6. Fig. 7-B represents a per left portion of the section, an ink su ture area in a fruit of a 4-2-2 plant. line was drawn part way (the area be­ Here the tissue in the suture area, about tween two arrows) along the epidermis six cells wide, is 4x as is the epidermis. to indica te the dividing line between the In Fig. 7-C is shown the suture tissue of diploid epidermis derived from the 2x another fruit, from the same 4-2-2 chi­ L-I and the tetraploid outer portion of meral trees as in Fig. 7-B which is 4x and only two or three cells wide, a con­ dition seldom found. Early and late ripening sports of peaches in which the Fig. 8. Shoot tip sections from a 2-4-2 ch i­ suture area ripens later or earlier than meral McIntosh apple. Top, longisection the rest of the fruit, are evidence of the of shoot apex. Bottom, transverse section importance of the fact that suture tissue of the twig, back of tip in top illustration. derived from L-I is usually several cells thick. JULY 1960, VOLUME 39, NUMBER 3 133 134 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. 9. A tmnsveTSe section of the maTginal pOTtion of a young leaf of a 2-2-4 chimeml NOTthem Spy apple. the cortical tissue derived from the 4x tetraploid part derived from 4x L-II and L-II. The continuous ink line in the inner diploid part derived from 2x L-III. cortical region separates the tetraploid The rest of the inner tissues of the stem part of the tissue (outer) from the dip­ were also diploid. The dotted line at loid part (inner). Thus it was found the left portion of the stem section was that in the apple as in peach, a 2x L-I drawn to indicate that at times tissue had given rise to a diploid epidermis development from L-II may extend alone. The cortical region is divided deeper in some parts of the stem, even cytologically into two parts; an outer into the pith region. The development- JULY 1960, VOLUME 39, NUMBER 3 135 .,

Fig. 10. A tTansveTSe section of a tTuit of 2-2-4 chimeml Winesap apple belaTe opening of floweT. al process just indicated is discussed on L-II consisted of one layer of cells im­ Page 167 in connection with the problem mediately next to both upper and lower of adventitious bud development. epidermises of the whole leaf and of all Figure 9 represents a transverse sec­ the inner tissue outside the ink line to­ tion from the marginal one-quarter por­ ward the margin of the leaL Tissue de­ tion of a very young leaf of a 2-2-4 chi­ velDped from L-III comprised the re­ meral apple. As mentioned before, L-I maining great bulk of the inner tissue gave rise to the epidermal tissue. But, of the leaf. I n the peach only an inner in contrast to the situation in peach, portion of midrib tissue was derived usually Dnly part of the internal tissue from L-III. In Fig. 9 the inner tissue in the apple leaf originated from L-II. within the ink line represents the tetra­ In the apple, tissue developed from ploid area derived from 4x L-III. Out- 136 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. II. A longisection of a fTuit of 2-2-4 chimeml Winesap apple befoTe openirlg of {loweT. side the line the tissue in the leaf sec­ the chimeral condition in this fruit re­ tion is diploid and derived from 2x L-I sembled remarkably that of peach illus­ (only the epidermis from L-I) and L-II. trated in Fig. 6, although morpho­ Figure 10 represents a transverse sec­ logically the two fruits differ. In Fig. tion through the seed cavity of a young 10 the tissue around which the ink line fruit of apple at the pink bud stage of is drawn represents the tetraploid por­ flower development. This was from a tion in this fruit; the ovular area and the 2-2-4 chimera I plant, and the pattern of outer portion of the fruit are diploid. JUL Y 1960, VOL UT\ I E 39, NU1\ IBER 3 137

In Fig. 11 is sh own a longitudinal nated [rom L-Ill. T he volume of tetra­ seeton of an app le fl ower at a stage of plo id tiss ue in the fruits of 2-2-4 chi­ fruit development similar to that in meras was varia ble. In some fruits the Fig. 10. This was also from the 2-2-4 whole inner portion of the fruit, excep t chimeral plant. The portion enclosed the ovular tiss ue and a very narrow strip by the ink line is tetraploid and the next to the epidermis, was 4x. In other other parts are diploid. Flower parts fruits only a trace of 4x tiss ue co uld be were more intensively studied in chi­ found and in still others tetraploidy was meral apples than in peach. In apple no en tirely abse nt. In the latter case the tiss ues or areas in tiss ues in any fl ower branches bearing frui ts with no 4x tis­ parts except in the fr ui t proper ori gi- sue in them had reverted to diploidy.

Fig. 12. V(LTiega ted leaves of a citn£s. Mutation in L-II.

III. Naturally Occurring Leaf Variegation and Fruit Sports and Their Propagation

In the preceding discuss ion, the man­ acterized by several shades of gree n cen­ ner in which plant sports, particularly trally and irregular areas of white mar­ chimeras, develop was explained on the ginally. Each color zo ne is sharply de­ basis of experimental findings. ' tVe now limited and the pattern is restricted sep­ turn to the description of specific types arately or independently on the two sur­ of na tural sports, vege ta tive variation, faces -of each leaf. Thus the variegation su ch as leaf variegation and fr uit sports, on the upperside of each leaf differs from and attempt to explain the way each that on the lower surface. The differ­ may have originated by comparing them ence in patterns between the two sur­ with the developmental processes of the faces of leaves is very imp ortant ch ar­ experimentally derived chimeras. acteristic of true variegations tha t are Variega tion in citnH and poinsettia.­ of geneti c origin. T he citrus leaf is com­ A familiar type of variegation occurs parative ly thick and composed of about in citrus leaves (Fig. 12) which is char- fifteen layers of cells. The number of 138 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. 13. VaTiegated leaves of a poinsettia. Nlutatio17 117 L-II. distinct shades of green in the variegated layers of cylindrical cells under the up­ leaf appears to be related to its thick­ per epidermis make up the palisade tis­ ness which in turn is rela ted to the num­ sue and are n ormally filled with disk ber of layers of cells in a cross section of shaped green bodies ca lled chloroplasts. the leaf. In the leaves of poinsettia and most other Variegation in poinsettia similar to plan ts the palisade tissue is one cell layer citrus is shown in Fig. 13. In poin­ wide. The region between the palisade settia with thinner leaves the number of tiss ue and the 10'wer epidermis is the distinct shades of color is less than in spongy tissue in which cells are actually ci trus. more rounded or many-sided and contain Ci trus and poinsettia leaves were cu t fewer chloroplasts. Cells of the epider­ crosswise in very thin sections to ex­ mal tissue, except the guard cells on each amine their structure from the upper to side of the oval shaped opening called the lower epidermis. Figure 14-A rep­ stomata, or stomates (breathing pores), resents a diagrammatic section of a lack chloroplasts. Therefore the epider­ citrus leaf, and Band C represent two mal tissue of leaves appears colorless, sections of poinsettia leaves. The small whereas the inner tissue is green. In the rectangles, some cross-marked and others diagra m the layers represen ting colored plain, represent cells. T he small narrow cells are shown at different depths in the rectangles at the upper and lower sides sections as is also variati on in number of the diagram represent cells of the leaf of ce ll layers. surface or epidermis. Areas with cross­ In the variegated citrus leaves more marked cells represent colored portions sh ades of green occur than in poinsettia. of the variegated leaves and the areas The degree of intensity of green (Fig. ~ithou t cross-marking the colorless por­ 12) is governed by the relative distance tIOns. In the leaves of citrus, the two of the chl orophyll-bearing cells from the JULY 1960, VOLUME 39, NUMBER 3 139

I COLOR LESS eRIGHT GREEN IUG HT GREEN I DA RK GREEN I MED.DARK GRN . I DARK GR EEN I VER Y LI GHT GRE EN l YELLOWIS H 11111111111.11111111 11111 111 1111111111111111111111111 1111111 II 1'11111111111111111111111111 111111 1111 11 11 11 1I1I rmfTl 1111111111111111111111111

IX

A ICOLO RLESS J ALMOS T COLORLESS I WED. DARK e ACK GRO UND DA RK EST I OARK I MED I U M DA RK IBACKGROUND BACKG ROUND BACKGROUND

l eR IG H T~oIH ' Co J DARK GR E EN I LI GHT ! BRIGHT GREEN !\I!\II I:I!I: I !I:I!!I !~~WW":;;~~W:'!I:'! VERYJC; OjO,..~q,~J LIGHT GR EE N DARK GR EEN IMEo. DARK I LIGHT -I GRE EN B I GREE c Fig. 14. A, diagTam showing leaf thickness of citTus and vaT)ling shades of green in a va?'iegated lea f. Band C, similm' diagrams faT poinsettia.

leaf surface, by the number of layers of somal chimeras can be studied cyto­ cells in the green tissue and by the mun­ logically in the earliest developmental ber of colorless layers of cells between stages of plant organs, such as a leaf; epidermis and deeper green tissue. Thus, but the color chimeras can be studied by careful examination of Fig. 14-A, usually in the more or less matured the reader can readily understand the plant organs. They cannot be traced basis for this fact. back to the growing point. Since color As pointed ou t earlier, the shoot is not present or detectable in meriste­ apex of a bud or twig has three primary ma tic-embryonic- tissues, it is detected histogenic (giving origin to tissues) lay­ in mature tissues, in mature organs, such ers: L-I, L-II, and L-IIL Studies of vari­ as leaves and fruits. ous types of diploid-tetraploid chimeral 'When variegated plants are observed plants, particularly of apple, showed that closely we may find individual leaves or the one-layered epidermal tissue is de­ branches with leaves entirely colorless or veloped from L-I; a po.rtion of tissue un­ entirely green. Occasionally we also find der the epidermis in leaf, stem and fruit some leaves, as in poinsettia and in priv­ is originated from L-II; and the central et, which are marginally dark green but tissue in these organs is derived from have a duller green central portion. A L-IIL Thus one might reason-and poinsettia leaf with such a make-up is rightly so-that the variegation in leaves shown in Fig. 15. These colored and of citrus and poinsettia is due to a nat­ non-colored tissues basically resemble urally occurring genetic color mutation certain diploid-tetraploid chimeral ma­ in L-II at the apex of a shoot or bud. terial. As thus in terpreted, the tissue in the In the leaf at the upper left in Fig. colorless areas in these leaves would cor­ 13 there is a small separate patch of respond to the diploid portion of the tis­ colored tissue. That patch was as bright sue in the cytochimeral leaf of the apple green as normal green leaves. The col·or­ shown in Fig. 9, and the colored area ing of the mutilated leaf at lower left, would correspond to the tetraploid tis­ especially at its outer left margin, was sue derived from L-IIL Thus, leaf varie­ also normal bright-green. ,!\Then sections gations just described would truly through the bright-green areas were represent a chimeral condition expressed studied it was found that there were as color variation, and are analogous normal green p las tids in the palisade to the cytological chimeras resulting layer, whereas elsewhere in the leaf the from chromosome variation. Chromo- palisa de layer lacked normal plastids_ 140 THE AMERICAN HORTICULTURAL MAGAZI NE

Fig. 15. Revened van:egation in a poinsettia leaf. JULY 1960, VOLUME 39, NUMBER 3 111

The relationship of the small bright­ Reimer showed the writer some changes green patch to the rest of the leaf tissue in two sports of Bartlett pear. One was is indicated in the upper left portion of of the 2-4-4 giant fruited type. On some the diagram B in Fig. 14. Diagram C trees of this sport completely diploid in this figure shows the condition found branches had developed. The other in the mutilated leaf, though reversed. Bartlett was a red colored sport. Breed­ 'When sections through the leaf shown ing results from the red sport had shown in Fig. 15 were studied, it vvas found that the color factor was in L-II. On that in the marginal areas, where the some trees of this sport some branches color was dense, all internal tissues were bore normal colored fruits, developed green. In the central area, where the on branches originating from L-I which color was dull green, the palisade tissue was presumably genetically green. In contained normal chlor.oplasts, and a the two pear sports and in the 2-4-4 chi­ layer of cells next to the lower epidermis meral peach, buds that had given rise also had gTeen plastids, bu t the cells of to branches which had reverted to norm­ the inner so-called spongy tissue were al had originated exclusively from L-I, colorless (diagrammatic partial repre­ not from all three histogenic layers, as sentation in Fig. 14-C). At the lower generally occurs; or from L-I and L-II left of the leaf (Fig. 15) there is a small alone, as quite often happens. Hori­ area that shows the typical variegated zontal cell division in epidermal cells, leaf pattern illustrated in Fig. 13. If that would account for the origin of bud we compare this peculiar color relation­ development from L-I alone, was ob- ship in the poinsettia leaf in Fig. erved in apple (10). 15 with the diploid-tetraploid tissue Whereas the development of the dip­ condition in the apple leaf in Fig. 9 loid-tetraploid chimeras was due to dup­ we see more precisely that the patterns lication of chromosome number in a formed in these two leaves resemble given layer of cells in a growing point each other closely. In the poinsettia leaf of shoot or bud, the origin of leaf varie­ the marginal tissue is normal green and gation and some fruit sports has been extends over a centrally colorless tissue. mostly of a genetic, or mutational na­ In the apple leaf the marginal tissue is ture. We may now apply the concept of diploid and extends over a centrally different cell layers in the shoot tips to located tetraploid tissue. In both the the development or occurrence of leaf pattern formed by two contrasting tis­ variegations and other sports to explain sues is similar; in one the difference is how they may have originated. genetic and in the other it is cytological. It may be concluded, according to the It was pointed out that certain dip­ concept of chimeral developmen t, that loid-tetraploid chimeral types are not variegation in the citrus and poinsettia permanently fixed or stable and that studied is due to a mutation in L-II they may change. This is because the which has suppressed chlorophyll devel­ cell division plane in L-II in a growing opment of plastids in cells of tissues orig­ point may change from vertical to hori­ inating from L-II. In cases where the zontal. This change of position in cell central area in the variegated leaves is division may also occur in L-I, very green, L-III in the variegated plant is rarely in some plants and not so rarely in normal. The appearance of green others. At the Plant Industry Station we patches over colorless tissue may be ac­ found on a 2-2-4 chimeral apple tree cepted as evidence that L-I, at least in completely diploid branches and on 2-4-2 poinsettia, is also normal and that cells and 4-2-4 chimeral peaches some of L-I in some leaves have divided later­ branches that were 2-4-4 and 4-2-2 re­ ally and given rise to green internal tis­ spectively. As mentioned before only sue. The appearance of leaves with a once was a small peach branch found pattern similar to the one shown in that showed a change from 2-4-4 to en­ Fig. 15 would result from division of tirely 2-2-2 type, diploid condition. This a cell in a horizontal plane in L-I in the was discovered because the peach was shoot apex. When this takes place, a highly sterile in both 2-4-4 and 4-4-4 con­ cell in L-II next to the horizontally di­ ditions. The branch that had become viding L-I cells might then be forced to fully diploid was fully fertile. take a position in a cell deeper and thus In Medford, Oregon, Professor F. C. take third rank position, so to speak. 142 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. 16. Variegation in privet. JULY 1960, VOLUME 39, TUl'vIBER 3 143

Va?'iegatiol1 in privet.-Having tvvo green leaves appeared ; thus a variegated variegated shrubs of privet by my home form co uld be changed back, or reverted, h as given me the opportunity to ob erve permanently to the normal green form. them closely and experimen t with them. Cell displacement p ll enomenon.-An In Fig. 16 in the first row of leaves at unexpected development was observed the top are typical variegated leaves with in variegated privet (a lso in EtWnyrmls, colorless or yellow margins and green see below). This was the appearance of center in varying patterns and shades. colorless or yellow patches on the leaves The color density in the green areas, as with reverse type variegation. Branches in citrus and poinsettia, was related to developed from axillary bud of leaves the distance of green colored layers of with reverse-type variegation (Fig. 16, cells from the epidermis and the number econd row) bore mostly leaves wi th the of colorless layers of cells between epi­ same make-up and occasionally some dermis and green tiss ue. In privet the lea ves were en tirel y green. But in rare number of shades of green ranging from instances some colorless patches a p­ very pale to dense green was intermedi­ peart:d on the rever e-type variegated a te between the co nditions in citrus a nd leaves. A leaf with such a colorless patch poinse ttia, presumably because privet is sh own in Fig. 17-D. A typically leaf h as an intermediate number of lay­ variegated leaf A is shown for compari­ ers of cells. In the second row in Fig. son. Leaf B h as an additional green 16 are leaves with normal colored green patch at right, derived from L-l. Leaf D margins and dull-green area in the ce n­ has a large colorless area on the upper ter. They represent the reverse type of right side and a streak of colorless area variegation similar to tha t in poinse ttia on the lower left side. In extreme cases (Fig. 15). In the third row one leaf is some leaves on twigs bearing mostly C­ entirely colorless and the others have type leaves were h alf colorless and h alf green patches of varying size developed green and some were even entirely color­ from L-I. Green p atches had occurred less (leaf E) . Some of the almost color­ on either surface of the leaves. In the less leave had in addition green patches bottom row the first leaf at left has larger developed from L-I, as shown on leaves patches of green than the leaves in the F and G. Growth from L-I on twigs third row; the second leaf is half yel­ bearing such secondarily developed low and h alf green; the third leaf is colorless leaves had resulted in the de­ totally green except for a little yellow velopment of completely green leaves area at its lower right portion; and the such as H . Figure 17, then, illustrates fourth leaf is entirely normal green. the sequence of changes from the typical­ Shoot growth in privet is rapid; thus ly variegated leaves through reverse branches could be forced out during the variegation to development of normal growing season by cutting shoots back green leaves. to a particular type of leaf to force ou t All evidence indica tes tha t variegation a branch from its axillary bud. This in the privet studied is due to a genetic technique proved very helpful and was change in L-II; and that L-I and L-III used repeatedly to determine what types are genetically normal. Therefore the of leaves would appear on the branches appearance of yellow tiss ue on the leaves forced out from any given point. Gen­ with reverse-type variegation could be erally, typically variegated leaves ap­ due either to a new mutation from green peared on the twig forced out from a to yellow in some cell, or most likely as bud at the axil of a variegated leaf. Bu t interpreted here, to one cell from a now and then on such a twig variegated genetically colorless histogenic layer leaves were interspersed with half-color­ h aving gotten in between two normal less and half-variegated leaves, or with cells of a genetically green layer. If that leaves entirely colorless, or with yellow was possible, then a genetically colorless leaves with a patch or pa tches of normal cell could give rise to a colorless patch, as color mostly marginally located. 'When that in leaf D, Fig. 17 . The size of a shoot was forced out from the axillary the colorless patch would depend on the bud of a yellow leaf the leaves were all developmental stage of a leaf at which colorless, except for occasional normal this displacemen t or disloca tion oc­ gTeen patches. From the buds of entire­ curred . If this had occurred in a grow­ ly green leaves only shoots with normal ing point before a leaf had started to 144 T H E ANIERICAN HORT ICULTUR AL MAGAZINE

A B

~-

' E F G

Fig. 17. Changes in pTivet fTOm vaTiegation to yellow by cell replacement phenomenon.

develop th en a whole leaf, or a sector blackberry (Fig. l 8) . Breeding evidence on a twig, m igh t appear colorless. If the showed that su bepidermal tiss ue and the replacemen t, or displacemen t, h ad oc­ res t of tissues in the stem of this thorn­ curred when a leaf h ad only partly de­ less sport were genetically thorny. Black­ veloped from the growing point then berry thorns are developed from the the size of a colorless p atch would b e epidermal tiss ue, and mutation in L-I only par tial or limited. h ad suppressed thorn development in A thomless blackbeTry sport.-Darrow the sport. T hus in some instances re­ (4) reported the appearance of a thorny placement of epidermal cells by under­ shoot on a branch of a thornless black­ lying cells m ay have taken place to ac­ berry sport known as Cory T hornless count for the appearance of thorny JULY 1960, VOLUME 39, NUMBER 3 145

Fig. 18. ReCtlTTenCe of a thOTl1Y shoot on a cane of a thomless SPOTt of blackbeny. Mutation in L -I . 146 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. 19. Variegation in Euonymous. jl1tbtation in L-llI.

Fig. 20. Variegation in Euonymous changing to yellow as in privet. JULY 1960, VOLUME 39, NUMBER 3 i'1 7

branches on thornless plants. Of cour e As was pointed ou t, variegated bushes of it could also be tha t in some cases a re­ Etwn)lmus frequently displayed branches verse mutation may occur in these sports which had reverted to normal and bore and the sport reverts to normal. It was green leaves entirely and permanently. noticed, h owever, that in the case of var­ Other branches, however, on the whole iegated privet yellow patches kept recur­ co ntinued to bear variegated leaves with rmg only in leaves on twigs bearing re­ green margins and yellow cen ters. At verse-variegation, C type, leaves (Fig. the beginning of February 1959, at one 17) ; such patches never appeared in the of our greenhouses I sa"v many cuttings entirely green leaves which had origi­ of variegated Euonymtts being grown. nated from normal L-I. Two of the young p lants had p'LtTe yel­ VaTiegation in Euo17-)lmus.-L eaves of low-leaved shoots along with branches Euonymus japonicus var. mediopictttS with typically variegated leaves. T hese (the spindle tree) are shown in Fig. two plants were repotted and care was 19. Leaf at left is normal green; middle given to make them gro'w at a fast rate. leaf is variegated, being marginally Since in privet the displacement of green and centrally colorless; leaf a t cells brought about a change in the com­ right is variegated but with a minimum position of the chimeral make up of of colorless area along the midrib. M u­ variegated leaves, the poss ibility that a ta tion of the colorless form in this plant similar phenomenon also occurrs in seems to be in L-III. A typically varie­ Euonymus was considered. If such is the gated leaf in this Euonymus plant should case, I thought it possible that, as in have resembled that of the poinse ttia leaf privet, in Euonymus also green patches shown in Fig. 15, the leaves of privet of growth may appear on some yellow in the second row in Fig. 16, and leaf C leaves. Such a possibility would be con­ in Fig. 17. Variegation in Etwnymus is tingent on the assumption that in some correctly genetical, judging from the fact leaves of Euonymus a cell with a yellow that purely green leaves appear on a twig factor from L-III has gotten between intermixed with variegated ones, and two genetically normal cells of L-II and twigs bearing only green leaves occur that genetically normal L-I h as remained along twigs bearing variegated leaves. intact in such a displacement process. In Furthermore, when shoots are cut back that event, some of the yellow leaves may to variegated leaves the new shoots bear be expected to show occasional p atches variegated leaves almost entirely and oc­ of green originating from genetically casionally completely green leaves. When green L-I. Two such leaves (on branches shoots are cut back to green leaves, the bearing yellow leaves), one with one shoots bear only green leaves. In the patch of green tissu e and another with variegated leaves of Euonynws there is two green patches, were actually fo und. perhaps at least one layer of cells of Figure 20 illustrates the sequence of palisade tissue derived from the genet­ changes in the phenomenon of cell dis­ ically normal L-ll over the colorless area. placement in the veriegated Euonymtts. It may be that some substance which A represents a typical variegated leaf of suppresses normal chloroplas t develop­ this plant developed from geneticall y ment in the tissue derived from L-III green L-I and L-II, and genetically yel­ diffuses into the ad iacent genetically low L-III. B is a leaf in which the in­ normal-green cells and affects the norm­ ternal tissue was derived completely al-green coloring there also, and thus a from green L-II. Leaf C was found on diffused coloration appears along the the branch immediately below the point edges of colorless central areas. This above which all the leaves were yellow; phenomenon obviously is not present in the lower leaves were typica lly varie­ leaves of poinsettia, privet, and other gated . In the yellow part at left of lea f species considered herein; consequently C, L-III h as replaced normal L-II and in the differently colored areas on these the part at right the varieg'ation pattern leaves appear sharply defined. has remained unchang·ed. Leaf D is com­ As this article was being written, the pletely yellow. Leaf E is the one yellow cell displacement phenomenon described leaf with a green patch. More leaves of above for variegated privet, and pre­ such character were found as the sumably in blackberry, was also found branches wi th yellow leaves continued to occur in the variegated Euonymus. to grow. The appearance of green 148 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. 21. Variegation in a tobacco plant. Mutation in L-II.

patches on yellow leaves indicates that from L-II can similarly migrate into L-I L-I in the yellow-leafed branch is norm­ remains to be determined. Such was as­ al. All these observations show that the sumed to have occurred in blackberry. variegation in Euonymus herein de­ Tobacco variegation and its genetic scribed is truly of a chimeral nature as analysis.-In this article the causes of in the other plants, and is due to a variegations described earlier and others genetic mutation present in L-III; and to be described farther on are considered that the displacement phenomenon is to be of genetic, nuclear, origin. As we the cause of the change from the varie­ saw in each case variegation was directly gated form to the completely yellow. associated with absence of normal chlor­ So far these observations show that oplastids in one particular histogenic a cell from L-III can somehow migrate layer. Therefore, it would be most in­ into L-II and thus change the chimeral structive if each material that has been arrangement of the apical layers. studied anatomically were also subjected Whether in privet and Euonymus a cell to breeding tests. JULY 1960, VOLUME 39, NUMBER 3 149

As it is not practicable to carryon an anthers and ovaries is derived, although extensive breeding experiment with occasionally exceptions may occur. In each sport described, a variegated plant monocotyledonous, grass-type, plants, of commercially grown tobacco (Nico­ however, the sexual tissue in anthers may tiana tabacum) was chosen for such a develop quite regularly partly from L-I test as an example, the result of which and partly from L-II. Such results were may apply to some cases of variegations, obtained in two cytochimeral monocots if not to all of them. Tobacco is herb­ produced by colchicine treatments. Ems­ aceous and an annual plant. Breeding weller and Stewart (21) obtained it in results from it can be obtained in a com­ cytochimeral lily (Lilium longiflorum) paratively short time. and Traub (28) in cytochimeral daylil y Two variegated leaves of tobacco are (H emerocallis) hybrid varieties. shown in Fig. 21. The variegation in these leaves appears similar to variega­ The variegated tobacco plant was used tions in leaves of poinsettia and privet. in breeding in a number of ways. In the In the tobacco plant besides leaves with first step a few of the flowers of the varie­ a central green area surrounded by color­ gated plant were self-pollinated. From less tissue there were found two leaves, self-pollination, a normal set of seeds shown in Fig. 21, each with a normal per seed-capsule was obtained. About green patch of tissue from L-I. Such a 2,650 seeds were sown in a flat. Percent­ green tissue can be seen at the upper age of seed germination was, normal for left side of leaf at left and a large patch this particular variety and very high. at the upper rig·ht side of leaf at right. All seedlings were lacking in chlorophyll, Therefore, as in other variegations de­ however, and reached only the coty­ scribed, the mutation resulting in mar­ ledonary stage (Fig. 22-A) and there­ ginally colorless tissue was considered to after all the seedlings died. In the sec­ be present in L-II, and that L-I and ond test, a few flowers of the variegated L-III were normal. plant were pollinated with pollen from Cytological studies of plants earlier a normal green plant of ths same variety. discussed have shown that the pollen Again a normal set of seeds was ob­ grains and the egg cells originate in the tained, and about 2,000 seeds were tissues developed from L-II. The evi­ planted. The germination was normal, dence of that was determined from but again all seedlings were colorless and studies of 2-4-4 and 2-2-4 chimeral plants. reached only the cotyledon stage (Fig. The 2-4-4 plants functioned as tetraploid 22-B) and died. In the thi,·d test a few plants and produced large pollen grains flowers of a normal green plant were because L-II in these plants was 4x. The pollinated with pollen of the variegated 4-2-2 and 2-2-4 plants functioned as dip­ plant. About: 4,500 seeds from this cross loid, and produced normal small pollen were planted, germination was normal grains because L-II in these plants was and all seedlings were green and con­ 2x. The nature of the diploidy or tetra­ tinued to grow normally (Fig. 22-C) . In ploidy in the plants studied was deter­ a fourth test, a few plants from the third mined by measuring the size of pollen test were brought to flowering and some grains, by microscopic studies of tissues flowers of these plants were self-polli­ in anthers and ovaries, and from breed­ nated; thus a second generation of seed­ ing results with diverse types of chimeral lings was raised. For this test, about plants. As stated previously, occasional­ 2,000 seeds were sown and the resulting ly L-I may give rise to internal tissue seedlings were green and grew normally growth in leaves, and the same may hap­ (Fig. 22-D). Not one seedling in all pen in anthers and ovaries. Thus in rare foU?- tests appeaTed as vaTiegated. This, instances some normal pollen grains may the writer judged, was a case of mutation be produced in anthers and normal eggs of cytoplasmic (non-genic and non-nu­ in ovaries of a 2-4-4 chimeral plant aDd clear) origin occurring in L-II alone; tetraploid type pollen grains and eggs and the defective nature of the L-II and in a 4-2-2 plant. Such a happening may the colorless tissue originating from it cause confusion when breeding results was entirely associated with the cyto­ of some plants are analyzed. However, plasm of the egg cells in the ovaries and as a rule in dicotyledonous plants L-U is was not carried by the pollen or male the layer from which sexual tissue in gametes. 150 THE AMERICAN HORTICULTUR AL MAGAZIN E

Fig. 22. FOUT gTOUPS of tobacco seedlings f?'Om bTeeding l'esult of vClTiega ted tobacco.

It m ay be concluded from this breed­ ance of p a tterns is the result of n ormal ing tes t with tobacco tha t variegation, tiss ues orig inating from normal histo­ as such, described in tobacco and in genic layers beside or above or below an other plants is n ot an inherited char­ abnormal colorless tiss u e. In the tobac­ acter. Variegation in these plants ap­ co, breeding res ults show that the ab­ pears as a vegetati ve expression due to normal color "vas due to a cytoplasmic certain chimeral condition s. T he appear- factor. JULY 1960, VOLUME 39, NUMBER 3 15\

Fig. 23. A yellow leaf sport in peach. lV[utation in L-Il.

SpOTts of peach leaf colo1".-vVhen Figure 23-A to D shows leaves of a yel­ cytochimeras of peach were studied low mutant of peach. On two trees about (13), it was found that L-I gave rise to eight years old, propagated from buds epidermal tissues in the leaf as in apple of a yellow-leaf sport of a peach, almost (11); but unlike apple, L-II gave rise all the leaves, numbered in several thou­ to the whole internal tissue in the leaf sands, appeared yellow and only very reaching into the midrib; and L-III gave rarely were leaves found with a patch rise only to a part of the tissue, centrally of normal green. When the sport trees located in the midrib. In peach, a mu­ were three years old, one leaf on each tation in L-II affecting chlorophyll de­ was half green and half yellow. The velopment appears to affect the whole shoots bearing these leaves were cut back leaf blade instead of color-pattern devel­ to the half-colored leaves and in both opment similar to that in poinsettia. In cases a shoot grew with completely green apple, L-II generally gave rise to the leaves along one sector of the twig. marginal part of the internal tissue of Along the other sector of the twigs leaves the leaf and L-III gave rise to the rest of were either yellow or partly yellow and the internal tissue. So far I have not partly green. These twigs were again cut seen a variegated apple leaf, but I would back, but the cuts were made to entirely expect-based on the cytochimeral green leaves. This time two new twigs study-that if variegation did occur in bore only completely green leaves and apple and affected the color of tissues have continued to do so ever since they originating from L-II it might be basic­ were forced ou t. ally similar to the variegation type found The experiment just described indi­ in poinsettia and privet. cates that the yellow mutation in this 152 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. 24. A mosaIc leaf sport zn peach. Nlutation in L-II.

sport is in L-II and that L-I which gave bud in the axil of such a half and half rise to occasional green tissue is normal. leaf that a branch with normal green The status of L-III in the peach sport leaves grew as explained above. Leaf E could not be determined because the leaf from the green branch is entirely normal tissue developed from L-III would be in green. The coloration in leaves of this the central area of the midrib and would sport changed in intensity from light not be pigmented. This experiment yellow to almost green under the effect confirms the cytological evidence that of favorable light and nutritional con­ the whole internal tissue in the peach ditions. leaf, except a part of the central portion The leaf sport shown in Fig. 24 ap­ of midrib, is derived from L-II and that peared on J. H. Hale peach variety. This a pattern of variegation similar to the sport may be compared with the familiar poinsettia type could not be expected to mosaic variegation of genetic origin in occur in peach. corn (maize) kernels and in flower color The peach leaves shown in Fig. 23 variegations of Verb ena which the writer range from entirely yellow to entirely had observed several years ago. In severe­ green. Leaf A is the typical yellow leaf ly mosaic areas of some leaves the tissue due to mutation in L-II. Leaves Band is mostly colorless with numerous de­ C are mostly yellow with patches of tached, sharply defined, islands of green normal green tissues originating from tissues in varying dimensions. The sport­ normal L-I. Half of leaf D is normal ing in this peach appears as being due green and half yellow. It was from the to an ever-mutating gene or some other JULY 1960, VOLUME 39, NUMBER 3 153 cytological factor in cells of L-ll which, dition is present toward the tip, strictly during the growth of the leaves, at times at the left of the midrib; in the fourth has no abnormal effect and at other there are two separated mosaic areas, times does affect unfavorably. Thus here one at the lower edge near the petiole and there cells carrying the gene for and the other toward the tip of the leaf; normal color give rise to normal patches in the fifth, at one side of the midrib, the of green tissue and cells carrying the mu­ leaf is heavily mosaic and at the other tated gene, or under some other cyto­ side very lightly so, in an area confined logical conditions, give rise to colorless near the petiole; and the sixth leaf is areas. But again, L-I being normal, in­ most severely mosaic as was shown ear­ ternal tissue occasionally developed lier in Fig. 24. from it would appear green. Leaf A ap­ Further noteworthy features observed pears to be developed internally half in this mosaic variegation: 1) So far, from normal L-I and half from ab­ during two growing seasons, no twigs normal L-ll. This analysis was confirmed appeared which bore only normal green when a small twig with leaves totally leaves, although branches were devel­ green was forced out from the axial bud oped from buds at the axils of normal­ of the half green and half mosaic leaf. appearing leaves. 2) Twigs grown from The comments made in the above buds at the axils of leaves with heavy paragraph were based on the condition mosaic usually bore similar leaves. 3) of variegation observed on two trees There appeared some mosaic areas which when they were one-year-old and had were at the very edge of leaves and sep­ only a limited growth. In the second arated from the midrib. 4) In some se­ year of growth these trees branched out verely mosaic parts there were numerous considerably and certain branches were small areas of tissues completely lacking cut back to force ample new growth in in color, surrounding tissue being green; order to study possible changes in varie­ in some other leaves small islands of tis­ gation as had been done in other varie­ sues were green and surrounding tissue gated plants described earlier. One of was white. 5) In many mosaic variegated the trees continued to produce predomi­ leaves green tissues were confined to cer­ nantly leaves with extreme mosaic-varie­ tain depths, beneath or above which, as gation. As was indicated above, when a the case may be, tissues were colorless_ shoot was cut back to a bud subtended Such a type of differential coloration by half mosaic and half normal green can be clearly seen along the midrib in leaf, a new shoot with a limited growth the fifth leaf (Fig. 25). appeared to bear only normal green If this mosaic-variegated condition leaves. The normal appearing branch was due to a mutation confined to L-ll, just referred to had proliferated during as the writer had thought previously, the second year's growth in to several there should not have occurred isolated secondary and tertiary branches. But mosaic areas, often confined to the very it turned out that the leaves on the new edges of leaves, especially areas farther branches were not all normal green as away from the petiole and away from had been expected, but all the twigs bore the midrib. Such a development does a mixture of leaves with varying degrees not parallel the development in leaves of mosaic-variegation, shown in Fig. of cytochimeral peaches. Odd location 25. A number of times when twigs were of some mosaic-areas suggests that this cut back to a normal appearing leaf, the particular disorder may not be genetic. new twigs arising from the subtended For such a variegation to be genetic, its bud consistently bore some normal ap­ development is expected to be more ran­ pearing leaves; some of the other leaves dom in its distribu tion over the leaves. were severely mosaic and some were in On the other hand, where normal green lesser degree mosaic. patches appeared and beneath or above In Fig. 25, the upper row shows the them tissues are colorless, as along the upper surface view of six leaves, the low­ edge of the fourth leaf in Fig. 25, it er row shows in corresponding order the would suggest that this disorder may be under side of the same leaves. The first genetic, as illustrated diagrammatically leaf at the left is entirely green; the sec­ in Fig. 14. In order to fully understand ond has a narrow mosaic area at right the nature of this mosaicism, last fall of the petiole; in the third, mosaic con- (1959) a few buds from a normal green 154 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. 25. Range in rnos.aic-vm·iegation pattern. JULY 1960, VOLUME 39, NUMBER 3 155

Fig. 26. A tHle mosaic-vaTietgation. An eveT-spoTting gene mutation !TOm pW'ple to g1·een. Mutation in L-IT. 156 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. 27. A yeil(}w leaf SPOTt in peach. Mutation in L-I.

peach tree were grafted on twigs with mosaic-variegated leaves along the oppo­ leaves severely mosaic. These buds will site side. Mutation in the seedling had be forced (in 1960) to growth in order occurred part way up the plant. This to test whether this particular disorder was judged from the fact that all the may be transmissible and therefore be leaves at the lower part of the plant due to effects of a virus. Certain possible were of uniform color. On the uniform­ developmental features during further ly colored side of the tree, new twigs growth of these particular variegated bore similar leaves and the twigs on the trees may help to resolve the present variegated side continued to bear varie­ case, and, incidentally, we may learn gated leaves. In Fig. 26, the top row more fully how some variegational shows the upper surface of five leaves symptoms may be properly diagnosed to and the bottom row the corresponding determine whether they are genetic or lower surface of each lea£. In both grou p­ pathological. ings the leaves at the ends represent en­ Figure 26 illustrates a kind of mosaic­ tirely purple ones, normal for this tree, variegation in peach leaf which appears and the three in between are representa­ to he truly of genetic origin. It was tive samples of variegated types in 'which found in 1959 on a purple colored seed­ light colored areas represent green color, ling. The change in color is from pur­ changed from purple. It can be seen ple to green. The mutation. appears to that the pattern of variegation on the be a so-called ever-sporting type, and it upper surface of each leaf definitely dif­ appears to be present in L-U. The varie­ fers from that of its lower surface. Such gated seedling when discovered showed a differential coloring almost consistent­ solid colored leaves along one side and lyon the two surfaces of a variegated JULY 1960, VOLUME 39, NUMBER 3 157

Fig. 28. A leaf sport of Amlia pennocki resembling chl01"Osis. Mutation in both L-ll and L-llI.

leaf is considered as a very useful diag­ A sport of Amlia leaf coloT.-Leaves nostic point in judging whether a varie­ shown in Fig. 28 are from a leaf sport gation is of genetic origin. of Amlia pennocki which was displayed Figure 27 shows variegated leaves at the 1960 National Flower Show in from a twig of a young peach tree result­ "Washington, D. C. At first glance the ing from a mutation originating in L-r. leaves appeared to be either affected by The sporting initially appeared as mo­ a disease or to show some sort of nutri· saic, bu t the mosaicism disappeared. tional deficiency. Close observation re­ When a twig was forced out from an vealed that many leaves had patches of axiliary bud of a yellow leaf, like that green tissue at their margins and a few shown at the far right in Fig. 27, all the were entirely green, while most ap­ leaves on that twig were uniformly yel­ peared to be completely defective, being low. Most of the leaves on the tree were pale green with chlorotic condition along green because L-ll in this plant was nor­ the veins. Presence of some leaves mar­ mal and only occasionally a patch of ginally green with chlorotic center and pale green area appeared on some green some leaves entirely green indicated that leaves. Pale green color in such areas the clone at the Flower Show represented was due to yellow color over green, yel­ a type of sport quite differen t from the low tissue presumably having originated obviousl y variegated forms as described from L-l. Twigs bearing only yellow in this article. The sport in the Amlia leaves were weak in growth and the plant is very instructive and helpful as leaves usually withered and died and a guide to the curious in the diagnosis none turned into g-reen as in another of a plant symptom whether it is caused sport earlier described. This account by an external factor, pathological or would indicate that this yellow muta· physiological, or by a mutation. tion differed from the previously de­ IE the leaves of Amlia had shown only scribed yello'w sport, since in that muta­ the chlorotic condition, it could be sus­ tion the yellow leaves could become al­ pected that the symptom is of an exter­ most green and survive the whole grow­ nal nature. But since some of th~ leayes ing season like the normal leaves. appeared defective and some others were 158 T H E AMERICAN HORT I CULTURAL MAGAZIN E

Fig. 29 Fig. 30 Fig. 31 Showing vQTiegatio l1 s In SansevieTia Pandanus Dracaena partly green and p artly defective, sim i­ dark-green horizo n tal banding 011 both lar in that respect to mos t variegations, leaves is normal; it is due to larger and and some appeared clearly normal, then greener chloroplas ts in cells in the dark the defective condi tion would be in the bands and smaller and paler green nature of a m utation. Therefore, th e chloroplas ts in cells in the lighter bands. mutation in this plant must h ave origi­ In the variegated leaf the fac tor fOl nated in L-II and that L-I is genetically colorless tiss ue occurs in L-l. T he width normal-green which accounts for the ap­ of colorless tissu e at the margins of varie­ pearance of normal-green areas in some gated leaves indicates the amount of ti s­ leaves and also for the development of sue nor mally d eveloped from L-l. It some entirely green leaves. It may be va ries gTeatly as can be seen from the ap­ assumed that L-III, like L-I was origi­ p arent complete lack of colorless tissu e nall y gen etically green but h as been re­ in the marginal areas of some leaves, in placed by a daughter layer of cells origi­ others from the presence of a slight n ating from the mutated L-II, h ence de­ amount of colorless tissu e and in still fective appearance of the entire internal others, as in the leaf to the right, very area of leaves of plants in th e ATalia considerable amount of colorless tissue clone. developed from L-l. N o normal plastids VaTiegation in monocotyledonous could b e seen in gu ard cells of the epi­ p lants. - In most monocots leaves are dermis of variegated leaves, and the cells elongated, as in grasses. T herefore when underneath the epidermis in green areas leaves of such plants become variegated, contained normal plas tids. the va rielZation appears in linear form Two leaves shown in Fig. 30 were instead of irregularly patterned as in from a variegated Pandan us veitchi poinse ttia. In Fig. 29 are shown a nor­ (Veitch's screwpine). The one at left mal leaf (left) and a variegated (right) was a typica l variegated leaf and that at of co ngo-snake-sa nsevieria (SansevieTia right was a colorless type occasion all y tTifasciata var. lauTenti). The gray and found. In this plant also the variegation JULY 1960, VOLUME 39, NUMBER 3 159

Fig. 23. Chimeml colorless SPO?"t in juniper. Mutation in L-I.

is due to a mutation in L-l. The fork­ contained green plastids. As in Sansevi­ ing in the green coloration in the mid­ e?'ia and Pandanus, L-I normally gives dle of the variegated leaf would indicate rise to varying amounts of tissue at the that during the early stage of its growth, leaf margins. In some cases there was no tissue development from the mutated noticeable marginal green tissue and in L-I was both marginal and central, others this was considerable. Leaf at whereas the growth of the colorless leaf right represents a condition in 'which was entirely from the mutated L-l. The green tissue ordinarily developed from status of chloroplasts in the variegated L-III in the variegated plants is elimi­ Pandanus was similar to that in the nated and is replaced by colorless tissue variegated Sansevieria. derived from L-II. It is possible, I pre­ In Fig. 31 are shown two leaves of a sume, for some leaves of the variegated variegated dracena (Dmcaena deremensis Dmcaena to develop as completely var. warnecki). Leaf at left is a typical green, just as some leaves of the varie­ one with normal green margins, a nar­ gated Pandanus were completely color­ row colorless strip next and a grey green less, by leaf development from L-I alone, at the center. A leaf like the one at but I did not find any in the limited right with colorless center is also found number of variegated plants I have seen. frequently. In this plant the mutation The complex variegation system found for colorlessness is in L-II. The guard in Dmcaena would indicate monocots cells in the epidermis of these leaves also may have three histogenic layers_ 160 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. 33. Detail of colm-less sport in jtmiper shown in Fig. 32.

VaTiegation in conifers. - Studies by as variegation in angiosperms, should Foster (22), his students and others have not appear. Hejnowicz (23), however, indicated that in the shoot apex of conif­ reported a variegation in Juniperus sa­ erous plants the cell division is random bina. In 1958, the writer saw a varie­ in contrast to that in the shoot apex of gated form of juniper, ]. squa.tama, at angiosperms where, as shown in this ar­ the National Flower Show in Washing­ ticle, the cell division follows a certain ton, D. C. Also, John L. Creech, Plant pattern, and cells are arranged in layers Industry S.tation, obtained from England in the shoot apex. In discussing this a variegated form of ]. expa.nsa nana of problem, the writer suggested in a pre­ which branches are shown in Figs. 32 vious article (8) that in the gymno­ and 33 . Variegation in all three juni­ sperms periclinal chimeral forms, such pers appears to be similar, in that each JULY ]960, VOLUME 39, NUMBER 3 161

B c

E

D Fig. 34. TiVhite-fiesh sport in fruits of nonnally yellow-fleshed Elberta peach variet)l. Mutation in L-ll.

resulted from mutation in L-I. The va­ In this respect juniper also resembles riegated plant of ]. expansa nana vvas privet, for example, where cell division only about twelve inches high and six in a horizontal plane seems to occur inches wide when the writer saw it. Some rather frequently. This would account small twigs of this plant were complete­ for the frequent appearance of internal ly colorless while tips of other twigs and tissue formation from L-I. The discovery some areas along others were colorless. of variegation in junipers indicates that The variegation, or the sport, in the some, if not all, gymnosperms and per­ juniper resembles leaf color sports of haps all angiosperms are characterized peach illustrated in Fig. 27, Sansevieria by primary histogenic-apical-layers, in Fig_ 29 and Pandanus in Fig. 30, all and that some gymnosperms are essen­ with colorless mutation in L-I. In the tially like the angiosperms as to the cell monocot Sansevieria and Pandanus activity in the shoot apices. whenever L-I carries the mutation its Fruit sports of peach. - Three fruit effect is obvious, for generally consider­ sports of peaches were brought to the able portions of tissue in the margins of writer's attention. One was a white­ the leaf blades originate from L-I. In fleshed sport of the normally yellow­ the peach the presence of mutation in fleshed Elberta variety; the others were L-I is apparent only when internal tis­ nectarine sports (fuzzless) of J. H. Hale sue of a leaf is occasionally developed in and Elberta varieties. Full details of the part or totally from L-I. In this respect first two sports were given in a previous juniper seems to resemble more the publication (18). Here only the most peach, a dicot plant, than Sanseviem pertinent points concerning the devel­ and Pandanus, monocot plants; except opmental features of the three sports are that in the shoot apices of the juniper, discussed. cell division must be occurring in hori­ When fruits of the white sport of El­ zontal plane more often than in peach. berta were cut into, most of them were 162 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. 35. Part-necta1-ine fruit sport of ]. H. Hale peach variety. Mutation in L-III. JULY 1960, VOLUME 39, NUMBER 3 163 bicolor and showed a pattern of white mal yellow fruits of the Elberta variety, and yellow flesh coloration resembling Genetically speaking, nectarine fruits leaf variegation of the poinsettia type. are merely fuzzless peaches. Nectarine In some fruits the flesh color was en­ fruits are firmer than peaches and have tirely white except in the suture line a distinctive flavor. In Fig. 35 are shown which in all cases was colored yellow. fruits of a part-nectarine sport of the Some others had only a very small J. H. Hale peach variety. Trees propa­ amount of yellow flesh besides the yel­ gated from this sport bore either entire· low suture. In Fig. 34 are shown dia­ ly normal peach fruits or normal peaches grams of four fruits with varying on some branches and part-peach and amounts of yellow and white flesh (the part-nectarine fruits on other branches. stippled areas of the flesh and sutures No trees or branches bore all nectarine­ indicate yellow color). In A there are type fruits. large areas of both yellow and white In Fig. 35 the upper fruit appeared as flesh; in B there is only a trace of yellow being wholly nectarine except for a wide flesh, and in C all the flesh except the band of fuzz along the suture. The fruit yellow suture is 'white. Diagram D shows at the lower left had a covering of fuzz a fruit cut in half longitudinally, and E over most of its surface with only small the same half cut transversely. areas fuzzless. The fruit at the lower Studies of cytochimeral peach fruits right was like a typical nectarine. The showed that a strip of tissue in the su­ fruit shown in Fig. I was also from the ture area is derived from L-I and that same sport; it had normal fuzz on its it is contiguous with the epidermal tis­ left side and practically no fuzz on its sue. They also showed that the flesh right. Although most nectarine-like and pit are derived from both L-II and fruits appeared to be without fuzz, close L-III. In the 2-2-4 chimeral fruit in Fig. observation revealed a limited amount 6 the pattern of tissue develop men t from of very short fuzz on most of them. The 4x L-III may now be compared with that nectarine-type fruits were somewhat of the yellow portion of fruit A in Fig. smaller than typical J. H . Hale peach 34. In the cytochimeral fruit the 2x por­ fruits; their flesh was firm and tasted tion of flesh corresponds positionally to somewhat tart. This was also true of the the 'white portion of the fruit of the flesh of the nectarine portion of part­ color sport and the 4x portion to the peach and part-nectarine fruits. The yellow portion. A color variation in over-all flavor of fruit of the sport was peach here described would indicate delectable and therefore this part-nec­ that in the white sport of Elberta the tarine sport might well be worth main­ mutation occurred in L-II. In breeding taining as a variety. In such a case the tests, the gene for white flesh in peach branches on trees bearing only peach is found dominant over that for yellow. fruits could be pruned off and leave In a normal diploid peach, the yellow only branches bearing mostly nectarine color is due to two genes for yellow col­ or part-nectarines. or. A change from one gene for yellow If this nectarine mutation had been in to one gene for white is sufficient to L-I, all fruits should have been fuzzless. change yellow color of peach fruit to If the sport of the J. H. Hale had oc­ white. Since L-I in this sport was ge­ curred in L-II, all trees propagated from netically normal yellow, the suture tis­ this sport should have borne nectarine sue derived from it had remained yel­ fruits. From breeding of J. H . Hale va­ low. The yellow coloring at the suture riety and of the sport only typical appeared both internally and externally. peaches have been obtained. For this Sports in stone fruits with a contrasting reason it was concluded that the sport­ color in the suture area were often found ing in J. H. Hale had occurred in L-III. and most of these could have had a f!;e­ The fruits of the nectarine sport of netic basis similar to the one here de­ the Elberta variety were entirely fuzzless sc.ibed to account for the distinct char­ at maturity, although fuzzy in the flow· acter in the suture. The sport here de­ er stage. All trees vegetatively propa­ scribed was not simply a chang-e in color. g-ated from it have borne only fuzzless Texture and flavor of the fruit were al$o fruits. In this sport the mutation was in affected, so that the fruits of the sport L-I. The L-I origin of this sport has had a much pleasanter taste than nor- been confirmed by breeding tests. When 164 THE AMERICAN HORTICULTURAL MAGAZINE cro ses were made between this sport and the vegetative to the reproductive stage, nectarine varieties the seedlings obtained that is into a flower bud, one of a group produced typical fuzzy peaches. All the of three (see reference 6) centrally lo­ fruits of the Elberta sport cracked at the cated cells in the apical dome of L-I su ture and remained considerably un­ divided horizontally instead of vertical­ dersized. ly, and the remaining cells continued to Breeding tests from the nectarine divide vertically. Thus, in one-third of sport of J. H. Hale also resulted in a the fruit the subepidermal tissue must progeny of typical peaches as just men­ have originated from the one genetically tioned. It was therefore assumed that normal cell of L-I and this sector showed in part-nectarine and part-peach fruits the normal dull color of the original va­ of ]. H. Hale the tissue development riety, ·while in two-thirds of the fruit the may have paralleled that shown in Fig. red color of the genetically red L-II 6. Positionally the "nectarine" tissue showed. It may also be that the appear­ would correspond to the 4x tissue in the ance of a normal colored sector in this cytochimeral fruit developed from L-III fruit was due to a reverse mutation from (Fig. 6). On this basis the nectarine darker red color of the sport. This effect in some fruits of the J. H. Hale change in coloring may more readily be sport may be due to proximity to the compared with changes in sports of epidermis of the tissue developed from Bartlett pear described elsewhere. It the mutated L-III. It may be assumed would seem if a mutation for red color that some substance from the "nectar­ in apple occurred in L-I, it would have ine" tissue developed from L-III dif­ no effect on coloring of fruits, since the [uses into the epidermal tissue and sup­ content of cells of the epidermis is prac­ presses fuzz development by preventing tically destroyed in mature fruits as normal growth of the epidermal cells pointed out above. A color mutation in into hairs (some chemical diffusion was L-I may be apparent, or expressed, only also suggested in variegation of Euony­ when internal tissue in the fruit is de­ mu.s ). Where fuzz has developed it would veloped from L-I. The presence of red indicate either that inner tissue in the color mutation in L-I may be suspected fuzzy region of the fruit had developed in some cases when fruits with bright entirely from normal L-II or that tissue red sectors occasionally appear among developed from mutated L-III was lo­ fruits of a variety that normally is of cated far deeper in the fruit. dull-red color. Color sports derived Fntit stJorts of apple. - In the apple from a mutation in L-I, which conse­ many color sports are known. It is sus­ quently has given rise to tissue growth pected that most of these are of chimeral from L-I, may be expected to remain nature. In most colored apples the col­ constant and not revert to normal color. oring matter is present in the subepi­ The two apple fruits shown in Fig. 37, dermal tissue. The content of cells of one large and one of normal size, were the epidermal tissue, especially in ma­ from a tree of Winesap variety. The ture fruits, is practically destroyed, large-sized fruits on this tree were most­ hence the epidermis is without coloring ly asymmetrical in shape. Cytological matter. In Fig-. 36 is shown a fruit of examination of growing points of twigs one of the red color sports of Stayman from branches bearing oversize fruits variety. In this fruit, about two-thirds showed a 2-2-4 type chimeral condition, of the area was red colored and one­ whereas the growing points of twigs of Lhird was of the duller but lighter color, branches bearing normal size fruits were typical of the original variety. This may 2-2-2 , entirely diploid. Thus the sport indicate that this red color sport of would breed as a diploid since L-II is Stayman originated as a mutation in diploid. The enlarged portion of the L-II and that the appearance of a nor­ fruit (Fig. 37) may be mostly tetraploid mal colored sector on the left was from and the shallo·wer portion mostly dip­ horizontal division of a cell of L-I which loid. This can be understood when the is normal and carries a gene or genes for giant fruit shown in Fig. 37 is compared normal, duller-red, color. It would seem "vith the cytochimeral makeup of the that in the case of the fruit shown in fruit shown in Fig. 10. Such asymmetry Fig. 36, at or before the time when a of fruits was also found in 2-2-4 type growing point was differentiating from peach chimeras. JULY 1960, VOLUNIE 39, NUMBER 3 165

Fig. 36. Light color sector on a fmit of a possibly dark red chimeral sport of Stayman apple. Mutation possible in L-II.

Fig. 37. Two fruits from a 2-2-4 chimeml Winesap apple; left is from a 2-2-4 bmnch; right is fT01n a diploid bmnch and shows the normal size fmit. 166 THE AMERICAN HORTICULTURAL MAGAZINE

,-. .x I

:- - ... , .I ' I I . \ , ,I \. , \ , . , I \ " , , " " , ------", , JlC , ------. , I . . I , , ,, -- -- - j ,

Fig. 38. LaTgest of tlwee fruits fTom Rhode Island Greening apple variety. The other two are fTOm a SPO?'t of Rhode Island Greening called "Sweet-and-Sour." D iagTOm of sweet and sour portions of the laTge fmit of "Sweet-and-SOUT" SPO?·t . lVI utation in L-LL. JULY 1960, VOLUME 39, NUMBER 3 167

Figure 38 represents an old pomologi­ The chief methods of propagation are cal curiosity, the "Sweet-and-Sour" apple a) bud grafts, b) shoot grafts, c) rooting sport of the Rhode Island Greening va­ of stem cuttings, d) rooting of leaves or riety. The bottom fruit, largest of the leaf segments, and e) growing of shoots three fruits in this figure, is Rhode Is­ from root cuttings. By use of methods land Greening, a tart apple: the other Q, b, and c, which permit a bud of the two are from a Sweet-and-Sour tree. The sport to develop into the new plant, the middle fruit, asymmetrical in shape, me­ chimera1 form of a sport may be main­ dium in size is typical of the sport. Some tained. It was shown previously that, parts of the asymmetrical fruit when although most buds of a sport repro­ tasted were either sweet or sour. The duce that particular sport, not every bud top fruit smaller, evenly shaped, was en­ may do so. It was explained that such tirely sweet. The mutation in this case a result was due to a change in the usual had been a change in the factor for sour characteristic mode of division of cells taste to sweet, but the mutation also had in histogenic layers, L-I and L-Il. Prop­ affected size of fruits. This mutation agation by methods d and e may be parallels the mutation of the nectarine used to produce plants originating from sport of peach and the diplo-tetraploid L-III, as will be pointed out below. chimera of the Winesap apple. The dia­ The value of some sports depends on gram in Fig. 38 was constructed on the whether they remain constant or revert supposition that in this sport L-I and to the normal type as may happen in L-III are normal and L-II carried the color or giant sports of fruits. Some mutation. Tissues marked I are derived color and giant sports may be made from L-I; II represents sweet flesh of the homogeneous throughout their tissues sport fruit derived from L-II; and III by forcing the developmen t of adventi­ represents sour flesh derived from L-III. tious buds or through root propagation On the left side of the diagram an area if either of these methods is feasible. is marked Ia to indicate that in some In 1946, the writer observed (9) that cases a part of flesh may be derived from adventitious buds, originating inside of L-I and will be sour. In actual tests, it bark, may be induced to develop on the was found that the bulged out parts of stem of some apple varieties. The ex­ the fruits tasted sour and the shallow periment was performed by cutting back parts sweet. All the small, even-shaped one-year-old apple trees to about twelve fruits were svveet. inches from the soil level and destroy­ Propagation of srjJO?' ts. - "Most of the ing all lateral buds by digging them out vegetative-type sports described herein with a knife. It resulted in adventitious present problems in propagation since bud development along the stem. Such at least initially they affect only a por­ buds originated in the phloem region tion of the plant tissues. Thus they dif­ inside the bark. fer from mutations occurring in eg~' By developing adventitious buds pure cells or pollen grains in flowers. which color sports were obtained from two will affect all tissues of a plant resul ting color sports of apple varieties: Improved from breeding. All Red McIntosh (a sport of McIn­ When a mutation occurs in a plant it tosh) and Scarlet Staymared (a sport of is present first in a single cell and affects Stayman); these sports had probably only that cell and tissues derived from originated from a mutation in L-II. It it. If the change occurs in a central cell is not known whether these sports are of a growing point (6), it affects only stable for the color or have shown a ten­ one layer or a sector of a layer and con­ dency to revert to the original lighter sequently, as we saw in the various red color of the varieties from which they sports discussed herein, it involves only had originated. A number of such color one tissue or a region in the internal tis­ sports in apples have shown. a tendency sues. The other tissues or areas remain to revert to original colors. normal. These facts must be taken into In order that certain problems in­ consideration when attempts are made volved in propagation of sport plants to maintain or propagate sports of a chi­ may be clearly understood, we need to meral nature. reexamine the apple stem section shown Methods of vegetative propagation in Fig. 8. There we find that the epi­ vary with the nature of particular plan ts. dermal tissue is derived only from L-I, 168 THE A1VIERICAN HORTICULTURAL MAGAZINE

Fig. 39. Adventitious shoot development. PUTe diploid and pUTe tetraploid shoots obtained adventitiousl)1 tTom a 2-4-2 chimeml McIntosh apple.

the outer portion of cortical tissue gen­ Results obtained when shoots from ad­ erally from L-ll and the inner cortical ventitious buds were forced out of the tissue, the conductive tissue [phloem, stem of one-year-old trees of a 2-4-2 type cambium and xylem (wood)] and pith McIntosh giant-fruited sport illustrate are mainly from L-llI. ' IVhen stem cut­ the case indicated above (16). Six one­ tings are rooted, the roots originate year-old trees of Giant McIntosh were from inside the bark, presumably also obtained from the Massachusetts Agri­ from the phloem region as the adventi­ cultural Experiment Station. On the tious buds in the stems. Consequently basis of cytological examination of a when certain sports are propagated by sh oot tip of one tree, this sport was con­ root cuttings or by adventitious buds we sidered to be a 2-4-4 type chimeral sport. may obtain some unexpected results. Hence an effort was made to obtain JULY 1960, VOLUl'vIE 39, NUMBER 3 169

shoots entirely 4x by forcing out adven­ seedlings). In Fig. 8-B the dotted line titious buds on the stem of the one-year­ was drawn to indicate the possible ori­ old trees. gin of a portion of deeper tissue in the Figure 39 shows adventitious shoot stem from 4x L-llI, derived from 4x growth on the stem of a one-year-old L-ll. It seems correct to assume that the tree of the Giant IVIcIntosh sport. In stem shown in Fig. 39 had the diploid­ Fig. 39-A, four bud swellings on the stem tetraploid makeup illustrated in Fig. are marked a, b, c, and d. The first 8-B; and that the buds a, b, and chad three buds are located along one side of risen from the region of phloem which the stem, almost on a straight line; the was 2x, and bud d had risen from the fourth, d, is lower on the right. Fig. region of the phloem which had be­ 39-B shows the same tree with shoot come 4x. growth from buds a and d; no growth occurred from band c. On cytological By the adventitious bud-method pure examination shoots from a were found tetraploid forms have been obtained also to be entirely diploid contrary to expec­ from 2-4-4 chimeral Delicious, Ontario, tation since, as pointed out in the pre­ Wrixparent (15) and from 2-2-4 chi­ ceding paragraph, the preliminary cyto­ meral Winesap apple (17, 25) varieties, logical examination of this McIntosh Adventitious buds along the internodal sport showed it to be a 2-4-4 type chi­ regions on the stems of Delicious, Mc­ mera; therefore, all adventitious growth Intosh, Ontario and Wrixparent were should have been homogeneously tetra­ developed with varying frequency on six ploid. The result thus obtained sug­ trees of each variety in the experiments. gested, as was later proved (16), that No such buds occurred on the stems of the sport had originated initially as a six Winesap apples when it was first at­ 2-4-2 type chimera and that the 2-4-4 tempted, or on the stems of twenty-four chimeral plant earlier reported (10) was trees used in a second experiment. derived from a change in the 2-4-2 chi­ Finally a larger number, sixty plants, mera. The branch from bud d was also were used in the hope that an "accident" examined and was found to be entirely might happen and that a pure tetraploid tetmploid. It was "luck," so to speak, form of Winesap would develop. Six that bud d had not developed along the months after all sixty trees were dis­ line of buds a, band c. In that case if hudded, a swelling appeared in the cal­ a shoot had grown from it, it would lused region on one tree shown by an have undoubtedly been diploid. arrow in Fig. 40-A, and two swellings on The developmental story of 2x and a second tree (not shown). On both 4x shoots in the giant sport of McIntosh trees the swellings gave rise to branches. can be better understood if we again Fig. 40-B shows the emerging of a shoot take a close look at Fig. 8. As stated pre­ from the first tree and Fig. 40-C its later viously, adventitious buds originate in development into a branch: the shoot the phloem region. If the stem in Fig. was pure tetmploid. The branches on 39 h;:!d had the chimeral makeup shown the second tree were both pure diploids, in Fig. 8-B. shoot growth from all adven­ presumably because this particular tree titious buds would have been diploid. had developed from a completely dip­ Therefore, it was most likely that the loid bud, as the 2-2-4 condition in this stem or shoot in Fig. 39-A originated chimeral Winesap frequently changes to from a bud with a dome which in part 2-2-2, or 2x, as previously described. was 2-4-2 and in part 2-4-4 (derived As is well known, in s'ome red color from 2-4-2). As a result in a larger part sports of apples, there is a tendency to of the stem the phloem and xylem tisoll'" revert to normal color. A red color sport must have originated from 2x L-ll, ,mel or Bartlett pear has shown such rever­ in a limited part from 4x L-llI. This sion. Here it would suggest that these sort of thing also occurred in peaches red sports may be made color-stable if shown in Fig. 5. (Incidentally, attempts 'aTlve nfi'tj,ous shoots · a1-e developed from 111'lde to induce adventitious bud growth them. It should be kept in mind, how­ on over fifty voung' peach trees of El­ ever. that adventitious buds from some berta and Golden 'Jubilee failed. The varieties may be obtained with ease writer, however, has seen adventitious and from others with considerable diffi- buds develop on some chance peach -cuI ty, if at all. 170 THE AMERICAN HORTICULTURAL MAGAZINE

Fig. 40. A pure tetmptoid shoot obtained adventitiously fmm a 2-2-4 chimeml Winesap apple.

In stem cuttings, when rooted, the which phloem tissue normally arises. roots, as stated earlier, arise from the Similarly, as roots arise adventitiously, phloem region as the adventitious buds. they also may have the genetic or cyto­ Buds that develop normally at the nodes logical makeup of L-llI. When L-llI of shoots arise usually from all three has a different genetic or cytological histogenic layers. Hence, leaf variega­ makeup from other histogenic layers of tions and certain fruit sports as described the plants, shoots developed from root in this article are maintained through cuttings may have only the character­ normal bud propagation. But adventi­ istics inherent in L-llI of the particular tious buds originate from cells in the chimeral plants, if in the meantime no phloem; they will have the genetic or replacement of tissue developed from cytological constitution of the phloem L-ll had taken place in the chimeral and usually therefore of L-llI from plant. JULY 1960, VOLUME 39, NUMBER 3 171

IV. "Graft-hybrids" and "Graft-chimeras"

Some of the readers may have come the scion and the other from the root­ across references to plants known as stock; (b) that the nuclei of the two gTaft-hyb1'ids or graft-chimems. In each cells have fused where scion and root­ case these are supposed to have origi­ stock have made a union; (c) that from nated by adventitious growth from the the united cell has developed an endo­ area of the graft union between two dif­ genous (internally developed), adventi­ ferent species, most of them belonging tious bud which has grown into a to two closely related genera. Some of branch. The course of these events the famous ones are BizwTTia orange, would require that the vegetative hybrid Cytisus (or Laburnum) adami, Cmta­ thus originated contains the sum of the ego-mespilus, pYTo-cydonia, Amygdalo­ somatic (body) chromosomes of the par­ penica, and perhaps a few more. These ent stocks. The graft-hybrid would then are described in a small book by Jones really be a true hybrid with a double entitled Plant-Chimaems and Gmft-H)I­ chromosome number. It should here be bTids (24). A very good discussion with emphasized that at present we have very a long bibliography on the subject was precise histological, cytological, geneti­ published by Swingle (27) . This topic cal and horticultural methods that has also been discussed interestingly by should be used to determine the exact '1\1" eiss (29) and Clowes (3). In recen t l'ature of such plant forms before con­ years, Bergann (1, 2) has been studying clusions concerning these plants are to some of these forms very intensively. be accepted at all. These plants when discovered were It appears that authentic graft-chi­ first accepted as being graft-hybrids. meras have been obtained experimen­ 'Winkler (30) appears to have set him­ tally only between Solonaceous plants self to prove experimentally that these (LyeopeTsieum and Solanum), plants were truly graft-hybTids. This he at­ which are herbaceous with succulent tempted to show by grafting nightshade stems. To this day, there has been no (Solanum nignlm) on tomato (S. lyeo­ authenticated record of anyone's having penieum) and tomato on niRhtshade. prod uced graft-chimeras expeTimen ta lly and by forcing adventitious bud growth between woody plants. The writer from the gTafts. He cut off the grafted strongly suspects that most, perhaps all, plants at the point of their graft-union. woody "graft-chimeras" that have been From the callused surface of the decapi­ reported to have originated by chance tated plants he obtained some shoots may not be really graft-chimeras, but are that had the immediate appearance of mutational chimeras originated in the the two components. He thought that manner described in this article for a these odd-looking plan ts were truly few fruit (for example, the nectarine graft-hybrids. Later Winkler (31) him­ sort of peach) and leaf sports. Bergann self was able to determine through cyto- (1, 2) and a number of other investiga­ 10Rical study that these were not graft­ tors (see references 1-2) believe, however, hybrids but were in fact graft-chimeras . that in three well known forms they are After graft-hybridity of tomato-night­ truly graft-chimeras. These are Cm.tae­ shade mixed plants was resolved in favor gus asnieTesi and C. dOl'daTi and LabuT­ of graft-chimera, the idea became cur­ num adami. The first two forms are rent tha t BizzaTTia orange, Cmtaego­ known as Cmtaego-mespilus, are consid­ mespilus, etc., also were graft-chimeras. ered to have been derived from grafts of It is surprising that even now the Mespilus gennaniea over Cm,taegtts terms graft-hybrid and graft-chimera are monogyna, and the third is considered used loosely as if they mean the same to have been derived from a graft of thing. For a specimen to qualify as a Cytisus pw'puTeus over La bU1'17um ana­ graft-hybrid it must be assumed (a) that gYTOides. Bergann reports (1,. 2 and union has actually taken place between personal correspondence) havmg ob­ two somatic (vegetative) cells, one from served the appearance of Mespilus 172 THE Ai'vLERICAN HORTICULTURAL MAGAZINE branches on C. asniel'esi and C. dm·daTi, of plants which may have resulted from and branches of Cytisus on Labumum union of two vegetative nuclei. These adami; and that he has been able ex­ reports usually contain references to perimentally to force out adventitious some suspected influence of rootstock on branches resembling the rootstock par­ the scion of grafted plants; and often ent in all three graft forms. It would be these reports carry genetic implications, most desirable if Dr. Bergann could pub­ and such results are given as indication lish such results with suitable illustra­ or grft-or vegetative-hybridity. If such tions. These might include initiation of influence is all that is implied by the adventitious bud development on the terms "vegetative-hybridity" and "graft­ stems of the supposed chimeral material, details of comparative vegetative growth hybridity" then the authors of such and certain gametophytic developments, works should find another word to ex­ for instance, comparative pollen grain press this kind of influence or phenom­ size and percentage of normal and ab­ enon. In order to avoid confusion and normal pollen. A publication of such a unnecessary misunderstanding the word character would be most welcome so hybl'id and any other words conveying that serious doubts about the origin of similar meaning should be strictly re­ such forms may be fully resolved. served for the specific meaning just One more comment: The term "hy­ pointed out. The term graft-chimera has brid" is used in the science of cytology, a valid meaning when applied to the genetics, horticulture, and taxonomy to two herbaceous solanaceous plants men­ connote union of two nuclei. In some tioned, but it should not be used with Russian and other scientific literature reference to woody plants, until all we find reference to both "graft-hybrid" doubts concerning such forms are fully and "vegetative-hybrid." In reading cleared. As to the terms "graft-hybrid" these reports, we do not find evidence and "vegetative-hybrid," they are fic­ that anyone has succeeded in demon­ tional and should have no place in scien­ strating the development of new forms tific literature.

v. References

1. Bergann, F. 1956. Untersuchungen an den 9. 1948. Chimeral apple sports BWten und Frlichten der Crat-aego-rnespili and their propagation through adventitious und ihrer Eltern. Flora 143: 219-268. buds. jaw'. Hered. 39: 235-242. 2. 1957. Die zlichterische Aus- 10. 1951. Tetraploid and diploid wertung der intraindividuellen (somati­ adventitious shoots from a giant sport of schen) Variabilitat von Kulturpfianzen McIntosh. jour. H ered. 42: 144-149. dUfch bewusste Auslosling von Regenera· 11. 1951. Ontogeny of tissues in tionsvorgangen. Wiss. Zeit. Piidagogischen stem and leaf of cytochimeral apples. AmeT. Hochschule Potsdam 3, 1: 105-109. JOU?·. Bot. 38: 753-760. 3. Clowes, F. A. L. 1957. Chimaeras and mer­ istems. HeTedity. 11: 141·148. 12. 1953. Pattern of tetraploidy in 4. Darrow, G. M. 1928. Notes on thornless the flower and fruit of a cytochimeral apple. blackberries. jour. H ered. 19: 139-142. JOUT. He?·ed. 40: 30-39. 5. Dermen, f.I a ig. 1940. Colchicine polyploidy 13. 1953. Periclinal cytochimeras and techmque. Bot. Rev. 6: 599-635. and origin of tissues in steam and leaf of 6. 1945. The mechanism of co l- peach. Ame?". jour. Bot. 40: 154-168. chicine induced cytohistological Changes in 14. 1954. Colchiploidy in grapes. cranberry. A mer. jour. Bot. 32: 387-394. jow-. He,-ed. 45: 159-172. 7. 1947. Periclinal cytochimeras 15. 1955. Three additional endo- and histogenesis in cranberry. Arne... jour. genous tetraploids from giant apple sports. 13 01 . 34: 32-43. A mer. jou... Bot. 42: 837-841. 8. 1947. Histogenesis of some bud 16. 1955. A 2-4-2 chimera of Mc- sports and variegations. PTOC. Arne... Soc. Intosh apple. jour. Wash. Acad. Sci. 45: Hart. Sci. 50: 51-73. 324-327. JULY 1960, VOLUME 39, NUMBER 3 173

17. 1955. A homogeneous tetra- 24. Jones, W. N. 1934. Plant chimaeras and ploid shoot from a 2-2-4 type chimeral graft-hybrids. Methuen and Co., London, Winesap apple. jou!". Hered_ 46: 244. England. 18. • 1956. Histogenetic factors in 25. Magness, J. R., and H. Dermen. 1957. An color and fuzzless peach sports. jour. Hered. internal polyploid Winesap apple. Proc. 47: 64-76_ Amer. Soc. Hart. Sci . 69: 65-67. 19. , and H. F. Bain_ 1944. A gen- 26. Satina, Sophie, A. F_ Blakeslee, and A_ G. eral cytohistolog'ical study of colchicine Avery. 1940_ Demonstration of the three polyploidy in cranberry_ Amer_ jour_ Bot. germ layers in the shoot apex of Datura by 31: 451-463. means of induced polyploidy in periclinal chimeras. A mer. jour. Bot. 27: 895-905_ 20. , and S_ L. Emsweller. 1953 . The 27. Swingle, C. F. 1927_ Graft hybrids in use of colchicine in plant breeding. Mimeo­ plants. jour. Hered. 18: 73-94. graphed. U. S. D. A., Plant Industry Sta­ 28. Traub, H. P. 1951. Colchicine induced tion, Beltsville, Maryland. Hemerocallis polyploids and their breeding 21. Emsweller, S. L., and R. N. Stewart. 1951. behavior. Plant Life 7: 83-116. Diploid and tetraploid pollen mother cells. 29. Weiss, F. E. 1940. Graft hybrids and chi­ Pmc. A mer_ Soc. Hart. Sci. 57: 414-418. maeras. jour. Roy. Hart. Soc. 65: 212-217, 22. Foster, A. S. 1939. Problems of structure, 237-243. growth, and evolution in the shoot apex of 30. Winkler, H. 1907. Ober Pfropfbastarde seed plants. Bot. Rev. 5: 454-470. und pflanzliche Chimaren. BeT. Deut. Bot. 23 . Hejnowicz, Z. 1956. The first periclinal Ge,·. 25: 568-576. chimera among Gymnosperms. Acta. Soc. 31. . 1935. Chimaren und Burdon- Bot. Pain., 25: 181-202. (In Polish with en. Die Losllng des Pfropfba tarde Prob­ English summary.) lem. Der Biologe 4: 279-290. A Book or Two

The Home Book of Flower Orchids In Australia Arrangements Fred Moulen. Charles T. Branford Com­ Using Oriental, European, and Colonial pany, 69 Union Street, Newton Centre 59, Massachusetts. (June 1958) (Printed in Containers Switzerland by Imprimerie Centrale Lusanne Estelle G. Easterby. Chilton Company, Book for Edita S. A., Lausanne.) 148 pages. I1lus­ Division, 56th and Chestnut Streets, Phila­ trated. $15.00. (Library). AHS Members' delphia 39, Pennsylvania. 1960. 156 pages. Price $12.75. I1lustrated. $3.50. (Library). The author, an Australian orchid grower, lec­ This book states in its foreword that the au­ turer and color photographer, has combined thor intends to teach young people the real these talents to produce this book. The book fundamentals of flower arranging. In the first contains only eight pages of text, as such, but 17 or 18 pages it attempts to give a background it also contains a hundred excellently rendered of Egyptian, Grecian, GothiC, Roman, Persian, color reproductions of flowers in the orchid Dutch and Flemish, French, Georgian, Vlctonan, family as grown (cultivated) in Australia. Some Colonial Chinese and Japanese arrangements. of the color plates are full page reproductions; The information conveyed IS sketchily dangerous all have lengthy captions on facing pages, al­ to a novice a'iTanger because it is much too brief most tantamount to text. The volume includes and treated so lightly. There are many com­ perfect color photographs of species and hy­ plete books on historical arrangements of van­ brids of Cymbidiums, Cattleyas, Vandas, Cypri­ ous periods that could be referred to as further pediums, Dendrobiums, Miltonias, Odontoglos­ study aids for young people. sums, and others. The accompanying photographs of interpreted It is an excellent book of color photographs J apanese arrangements are quite good and seem of some of the better known orchids, but it is well thought out and executed, although there shy on much that the commercial grower and is a mixture of Japanese and Chinese in contain­ hobbyist seeks to know about the Australian ers and accessories, which is completely accept­ orchids, such as cultural practices, and especially able for home arrangements. Some very inter· information on and pictures of the orchids en­ esting and easy to execute designs are pictured demic to that country. in a short chapter entitled Modern Arrange­ E. G. ments. Discussed, but all too briefly, are the subjects of growing suitable material for arranging, con· tainers, mechanics and accessories. Treated lightly also are the Elements of Design, Color and The Principles of Design. The reviewer Tree Fruit Production feels that these points would be much clearer to the arranger were they related to direct ex­ James S. Shoemaker and Benjamin J. E. amples using photographs of arrangements, Teskey. John Wiley & Sons, Inc., 440 Fourth especially where color is concerned. Avenue, New York 16, New York. 1959. 456 Twelve lovely color plates occupy the center pages. I1lustrated. $6.95. (Library). of the book. To the critical judge some would have a few design flaws, but nothing serious This new text deals with the propagation, cul­ enough to discourage the intended young reader. ture, and handling of tree fruits in the United The section on Suitable Anangements for Dif­ States and Canada. Suitable for the beginners' ferent Areas of the Home pictures some lovely course in pomology, it will also serve as a gen­ arrangements. The majority of these are simple eral reference book on orcharding. Considerable vertical or nearly vertical arrangements using emphasis is placed on recent scientific develop­ but a few flowers. A chapter on Church Ar­ ments. Such fields as spraying for fruit thinning rangements pictures one good one. Lastly in are included. There is somewhat of a tendency this book there is a rather incomplete discussion to include too many subjects at the expense on dried materials; how to preserve materials of adequate discussion. The text is well illu­ and inanimate objects that might be used by strated and many references are suggested for the floral arranger. supplemen tal reading. VICTORIA K. ANGEL H.W.

(Books available for loan to the Membership are designated: (Library). Those not so designated are in private collections and are not available for loan. Books available for sale to the Membership are desif!nated with the special reduced price and are subject to the usual change of price without notice. Orders must be sent through the American Horticultural Society accompanied by the proper payment. Please allow two to three weeks for delivery. Those not designated for sale to the Membership at reduced prices can be purchased through the Society, however, at the retail prices given. In these instances the full profit is received by the Society to be used for increased services and benefits of the Membership.) [174] JULY 1960, VOLUME 39, NUMBER 3 175

The Book of Planters This book should encourage many to grow camellias for the first time and should encour­ Robert Scharff. M. Barrows and Company, age many others to find new ways to use the Inc., 425 Fourth Avenue, New York 16, New plant in the land cape. T he book is interesting, York. 1960. 191 pages. Illustra ted. $3.50. well illustrated and provides profitable informa­ (Library.) tion for all persons interested in camellias. A detailed and well-illustrated guide on in­ LEMOYNE HOGAN terior and exterior planting boxes. Informative and well-written, the book covers all important phases of this increasingly popular form of gar­ dening and should serve adequately as a ready reference for planter constructIOn, plant ma­ terials, and planter problems. The American Camellia Yearbook, C. T. J OHNSON 1959 Edited by Herbert S. Wolfe. American Ca mellia Society, Box 2398 University Sta­ tion, Gainesv ille, F lorida. 1959. 388 pages. Camellias For Everyone Illustrated. $6.00. (Including Membership). (Library) . Claude Chidamian. Doubleday & Company, Inc., 575 Madison Avenue, New York 22 . New T he 1959 Camellia Yearbook is a fi ne collec­ York. 1959. 191 pages. Illustrated. 3.95. tion of articles on the camellia which are (Library.) grouped together into five major sections; Rela­ tives, Species and Varieties; Diseases and In­ T his book is especially beneficial (or per ons ects; General Culture; Plantings and Gardens; just becoming interested in growing camellias. and Awards, Shows and Varietal Registrations. The author has go ne to some length to co nVll1ce In each of these sections there is an article, or the reader that camellia growing is easy, simple, two, that has lasting information in the better and requires little time and effort. He attempts understanding of this plant. In the first section, to break down the barrier of legend a nd myth these wou ld be articles such as those dealing tha t camellias are fragile, rare, and exotic. In with the possible cause of fa lse h ybrids, the this attempt, he somewhat over-emphasizes tl~ e chromosome numbers or the description of new ease with which these plants can be grown 111 types. different locations and under different co ndi­ The sections on Pest and on Culture each tions. In a later chapter, however, he gives a have articles that report on the research find­ thorough discussion of how the camellia can be ings with this plant. These a re reporting on adapted to conditions which will induce favor­ pest controls, cold hardiness, nutrition, and able OTowth under varied climatic condition s. propagation. They will interest the serious stu­ A list of the most important species, varieties , dent of this plant as well as some written in a and mutations is given with descriptions ot more popular manner that will appeal to the flower form and color. This useful guide also hobbiest. gives information as to the time and length ot Several gardens or collections of camellias are blooming period and landscape va!ue. . described, as well as varieties growing on the The author has done a superb Job of bnng­ outer edges of the camellia "belt." R eports of ing to the l'eader's attention new and interest­ this kind give h elp and encouragement to those ing ways to use camellias in the landscape. T he active fanciers of this flower. chapter covering uses of the glamorous camellIa Society information is included as the an­ as a valuable landscape plant is one of the high- nual report of new varieties registered, show ligh ts of the book. ., awards, and membership list. It even includes Information is also given on grow1l1 g camellI as a none horticultural item; a poem on the under glass. Culture and growing habits are ca mellia. There are articles to appeal to all in­ discussed in detail. terested in the camellia. A good yearbook. A chapter is devoted to ways camellias can be CONRAD B. LINK used to beautify the interior of the home. Used either as bonsai or arrangements to spotlight a goro-eous bloom, camellias are excellent for in­ doo~- use. The au thor goes further in glV1l1g step-by-s tep instructions for making camellia corsages. The chapter devoted to collecting, buying, Peonies, Outdoors and In and propagating contains p~'o fitabl e .i~form at ion for those who are plann1l1g addItIOnal pur­ Arno & Irene Nehrling. H earthside Press, chases. A valuable discussion on camellia cuI· Inc., 118 East 28th Street, New York 16, New ture is presented. The author po~n. ts ou~ t.hat York. 1960. 288 pages. Illustrated. $5.95. camellias must be adapted to conditIOns SImIlar (Library). AHS Members' Price $5.06. to their native environment to insure successful growth. . This most effective presentation of the peony Adequate information is given on the m am· is marked by three impressive characteristics: the tenance, pests, and diseases of camellias. extensive scope of the book, embracing a many­ The final chapter on camellia literature .is faceted approach to one of the great ornaments es pecially valuable to ~he read~r. ~ bnef dl ~­ of the garden; the authoritative grasp of the cussion of the most mformatlve lIterature IS subject shown by the writers; and their own en­ presented. thusiasm which they communicate so happily 176 THE AMERICAN HORTICULTURAL MAGAZINE to their readers whether connoisseu rs or begin­ terials, containers, and access01'ies that seem to ners in peony culture who can do little lUore lack the elegance, grace, and dignity associated than recognize tha t Fes tive Maxima is a peony. with and traditional to religious fl oral arrange­ T he subjects embraced are all-inclusive: his­ ments. torical background; graphically clear botanical A chapter on Church Arrangements pictures cl ass ifica tions; the peony calendar; design in the six arrangements of p redominantly fresh ma­ garden; characteristics and cross-classifica tion o f teria ls of only modera tely good design. All seem varieties; culture; many aspects of mdoor use again to lack the grace, charm , and purity of and practice; and a supplement co vering peony balance so appropria te and fitting to the l'elig­ gardens, priva te, public, and commercial. iOll s them e or chu rch setting for floral deco­ I t is difficult to choose which sections are most ra tion. successfully done. T he presenta tion of varieties The all important phase of design in the a r­ by many cl ass ifica tions form an excellent hand­ rangements is discussed briefl y, but the many book for selection: by color, height, time of fl aws are apparen t; most noticeably in the Scale, flowering, fo liage, fragrance, and garden p ur­ Proportion, and in many cases the size of the pose. I t is good to see the h ybrids getting the accessories used. attention tha t their new world of b rilliant, clear Included is a brief R eference List; a list en­ colors deserves. Interes t would be added for titled Symbolism of Flowers, Leaves and Fruits many co llect01's if the hybridizers names had wi th common names of the ma terials used . Also been used m 01'e freely a fter varieties. The au ­ included is a list, again with common names thors have been careful not to overpower the only, of some fl owers, foliages and fruits of the reader by p resenting an all-inclusive list of Bible. :varieties, but have exercised restraint and dis­ VICTORIA K. ANCEL crimination in their choice. In noting the carefully detailed steps in cul­ ture and garden design with peonies, one needs to rem ember tha t actually few flowers produce Form and Space of Japanese wi th less drudge ry "an attractive gard en with a Architecture m inim um of work." Collectors in many horticul tu ral fi elds have Norman F. Ca rve r, Jr. Published by Shoko­ learned the incalcul able value of visiting other kusha Publishing Company; distributed by gardens to see new and coveted varieties. It is Charles E. T uttle Company, Rutland, Ver­ hoped that many garden books will emulate this mont. 1955. 200 pages. 164 illustrations. volume in its supplement that locates geograph­ $12.00. ica ll y and gives pertinent d ata on m any gardens where peonies can be seen at their best. T his bi-lingual book, addressed primarily to T he text is written in cl ear, effective p rose, architects, co ncerns itself with two elements of but illumined with touches of imagery tha t are design-Form and Space. These are defin ed and appealing-"red stems and sea-green lea fl ets," discussed, important since the concepts as pre­ " the peony, tha t peacock among fl owers." T h e sented must have determined the illustrations. many well-chosen pictures, with some b rilliant In his brief preface, the author writes : "I color inser ts, tend to make the text much mo re have assumed , therefore, some basic acquaint­ graphic and usable. ance with J apanese architecture" " " and p ro­ If a negative note must be struck, it might be ceeded above and beyond these particulars to that too much space is devoted to working out defin e the general organiza tion of J apanese combinations with other flowers, something tha t architectural design and its implications fo r perhaps ,m ost gardeners prefer to achieve under modern architecture. Su ch an approach, of their own inspira tion. course, is concerned not with fact alone, but I t will probably be many years before there is interp reta tion of fact." issued another volume that will take away from For readers o f this Magazine, who may not the Nehrlings their distinction of having given have the " basic acquaintance," the reviewer the peony world its definitive text. pres umes to r emind them that the materials shown are p rimarily wood, and in lessening de­ FRAN K J. G ILLIAM grees, stone, tile, plas ter, bamboo, straw, and paper. Wood shows every degree of finish, from raw forms to hand polished; stone, from natural fo rms, p articularly river worn gravel, sand, to Religious Themes In Flower carefully cut. For many of these old buildings, only the most p rimitive tools were available Arrangement and no modern means fo r lifting great weights; Ruth E. M ullins. H earthside P ress, Inc., 118 also, tha t hand labor of incredible skill carried East 28th Street, New York 16, New York. out the work. 1959. 122 pages. Illustra ted. $5.95. (Li· One might remind himself also, tha t J apan, b rary). AH S Members' Price $5.06. an island country, has torrential rains, in the areas reported, n ot much snow, brilliant sun­ In the beginning of this hook the author a t­ shine. These, too, affect design. tempts to cover (but does so very inadequately) The reader interested in gardens will find the Great R eligions of the World in eight h alf­ nothing of plant ma terials, but a wealth of study pages of text. Each page is accompanied by an of the relations between building and garden arrangement. m an y of which incorporate drift­ as they r elate to one another and interpenetrate. wood , small accessories, and d ried materials, and Mr. Carver has shared his great experience some are placed on painted wooden bases. with a purpose, but anyone may reap his own Of the 64 or so arrangements pictured , more particular harvest of ideas and inspirations. than half make use of driftwood, dried rna· B. Y. M . The Gardeners' Pocketbook

W. H. HODGE

Meriania nobilis Lerest still continues, it seems worthwhile to summarize what is known about this endemic Colombian tree and particular- 1y a bou t its potential as an ornamental. The genus MeTiania (honoring the While residing in :Medellin, Colom­ German naturalist-traveler Maria Sybil bia, during 1945 and 1946, I had occa­ Merian) includes some thirty or more sion to become acquainted with what is species of tropical American trees of the undoubtedly one of the most showy of West Indies and northern South Amer­ small flowering trees native to the Amer­ ica. MeTiania nobilis was first named by ican tropics. This is M eTiania nobilis, the botanis t, Triana, in 1871 from plants more familiarly known to the people of collected near Rio Negro, an agricul­ the Department of Antioquia where it is tural community lying to the southeast endemic as amaTTaboyo or maTmboyo. of Medellin, capital city of Antioquia. Although a member of a prominent Me1'iania nobilts, as observed by this tropical family, the MELAsToMATAcEAE, writer in the classical area, is a small tree which can boast of a number of showy seldom more than several inches in di­ plants (e.g. Tibouchina semidecandTa) , ameter and ranging upwards to fifteen few, if any, can compare in beauty of or twenty feet tall. Its growth habit is flower with this species. - not particularly ornamen tal, being open The publication of a color photo­ and even rather straggly. The large graph of MeTiania nobilis (Natuml His­ ovate leaves are, however, very attractive tory, Vol. 56, June, 1947) evoked com­ with their dark-green upper surfaces ment concerning the possibility of culti­ strongly nerved with palmate venation vating the species and because this in- so characteristic of the Melastoma [177] 178 THE AMERICAN HORTICULTURAL MAGAZINE

Family. When in flower the .aman-ab?ya transplant the trees to local gardens. Nor makes up for all its vegetative de.fiClen­ did I learn of anyone who had tried to cies. The large flowers (up to three ll1ches grow this tree from seed. There must across) are beautiful not only in form have been efforts made, for the local but also in color, the buds and newly opinion was that the plants were my­ opened blossoms being a gorgeous pink corrhizic and would not grow in the (nearest to RHS Peony Purple 729/2-3) , absence of certain soil fungi. changing to rose as they become older. Believing that it might be worthwhile The yellow stamens with their character­ to see whether Meriania nabilis could be istic dark horn-like appendages made a grown from seed under cool greenhouse striking pattern at the center of each conditions, I wrote a good friend and open bloom. Several flowers are borne former colleague, Carlos Garces O. of the in each cluster to form rather large, Facultad de Agronomia at Medellin. stalked racemes. Three ounces of the very fine seed were As desirable as the amarrabaya would received in September, 1956. This was appear to be as an ornamental, all at­ divided with several other botanic gar­ tempts to cultivate this species have ap­ dens and arboretums both in this coun­ parently failed. To help future attempts, try and abroad. At the same time, a a , few remarks about its native habitat small quanlity of soil collected from be­ may be in order. The tree thrives in the neath trees in the wild was forwarded low, open forests or woodlands which to the United States Department of still cover the rather precipitous ridges Agriculture with the hope that it might of the central Andean ranges surround­ be of advantage in supplying the neces­ ing the valley in which the mile-high sary soil fungus for seedlings to be grown city of Medellin is located. These ridges at the Plant Introduction Station at lie at elevations of from seven to eight Glenn Dale, Maryland. thousand feet where the climate is cool­ At Longwood Gardens seed was temperate rather than warm-tropical. planted on several acid media including Because of the low latitude the annual a peaty compost as well as the standard and daily range in temperature is not shredded sphagnum mix. Germination great, but probably would run between was excellent in both cases although the fifty-five to seventy-five degrees Fahren­ young seedlings subsequently made bet­ heit. At this elevation precipitation is ter progress in the sphagnum. During considerably greater than in the Medel­ the next two years a few of the seedlings lin valley, but the pattern of precipita­ attained a height of ten to twelve inches, tion is the same with two dry seasons but most of them seemed to be unhappy and two wet seasons each year. and eventually all were lost in the fall of A decade ago the species was quite 1959. Similar results were attained at common around Santa Elena lying near Glenn Dale, though they were unable to the height of land on the road between maintain plants after 1958. Medellin and Rio Negro. Here it could In spite of these failures the amarra­ be observed in flower during the Fall, bayo still warrants further trial. The particularly in the month of October. best spot to initiate controlled cultural In its native haunts it associates with trials would be in Medellin, Colombia, such sister melastomaceous species as the at the Facultad de Agronomia where magenta-flowered Tibauchina lepidata proper facilities exist for horticultural (Siete CuerO's) and the white-flowered testing. At the same time it would be Miconia theaezans, common shrubs or worthwhile to try this plant again in this small trees of the rather open woodland country. Keeping in mind that Meriania borders fringing the 'road. The presence nobilis is an acidophile, that it inhabits of a number of ericaceous genera in the the cool, moist Andes where it suffers same plant communities seems to indi­ neither high temperature nor frost, it cate that soil conditions are on the acid would seem that the most likely spot for side. successful trial outdoors in this country During my sojourn in Colombia, I would be in the San Francisco Bay area could learn of no one who had success­ or in greenhouses under glass anywhere fully grown the amarrabaya as an orna­ where summer temperatures can be kept mental although some unsuccessful at­ under seventy-five.-W. H. HODGE, Lang­ tempts had apparently been made to waad Gardens, Kennett Square, Penna. JULY 1960, VOLUME 39, NUMBER 3 179

W. H . HODGE Azaleas flourishing in raised bed of acid soil in Warwick) Bermuda.

A Technique for Growing Azaleas problem to be solved is then quite ob­ in Bermuda vious:-to provide a suitable acid soil. Assuming a suitable soil, the next prob­ lem is where and how to use it. Finally, Except in the marshes, the soil of Ber­ since azaleas are extremely dimate-con­ muda has been formed entirely from the scious, many requiring an uninterrupted weathering of a thick limestone cap. It winter dormancy, there is the further is, therefore, alkaline with a pH ranging problem:-what azaleas to try, consider­ from 7.5 to 8. Many kinds of plants ing the comparative mildness of the Ber­ luxuriate in its rich, warm, red-brown muda winter and the long, warm sum­ loam, but hardly azaleas. And the soil mer. contains far too much lime for a substan­ My first attempt at arriving at a satis­ tial lowering of the pH by means of sul­ factory technique was to make up a soil phur or peat. from a mixture of imported peat moss, In attempting to develop a successful composting materials and local sawdust azalea technique for Bermuda the first with fertilizers added plus a chemical 180 THE AMERICAN HORTICULTURAL MAGAZINE

w. H. HODGE Luchu azalea (RhododendTon scabTum) in BeTmuda gmwing on a mound of acid soil sepamted fTom limestone soil beneath by a sheet of aluminum. (see loweT Tight comeT) for speeding the breaking-down process. florist's azaleas; three plants listed as After a few months the "soil" was placed Rhododendmn sp., "China" bearing the on top of the ground as a raised bed federal Plant Introduction No. 199,300; abou t ten inches deep and held in place and thTee plants representing P. 1. No. by upended logs of Bermuda cedar sunk 199,302. into the ground. It was felt that holes Avid invading roots from nearby dug in the ground and filled with acidic shrubbeTY, an impaired pH due to a material would not be satisfactory in this careless workman's shovel, and absence climate since lime would leach into the from Bermuda during the summer did holes with every heavy rain. For about not help this first experiment. In some­ half the day the bed would receive full thing less than the fullness of time the sun. Then my friend, Walter H. Hodge, florist azaleas died, and so eventually did who at the time was with the U. S. De­ the three representatives of P. 1. No. partment of Agriculture, Plant Explora­ 199,300, though for awhile they looked tion and Introduction Section, Beltsville, promising. But the three plants of P. 1. Maryland, kindly had sent to me a small No. 199,302 survived the tough condi­ consignment of azaleas for trial:-six tions, and when one of them put out its JULY 1960, VOLUlVIE 39, NUMBER 3 181 first flowers, I was amazed at their in­ -except 'President Claeys,' which is not tense beauty. This gorgeous red azalea satisfactory. In particular, the gorgeous from Formosa, with its distinctive glossy Luchu azalea and indica clone 'George dark-green foliage and attractive lax Lindley Taber' appear to be perfectly habit of growth, has recently been identi­ adapted to the Bermuda climate. Both fied by B. Y. Morrison, creator of the are very fine indeed. Eventually the Glenn Dale Hybrid Azaleas, as un­ proximity of the masonry may adversely doubtedly a form of Rhododendmn affect the soil pH, but it will probably scabrum, the Luchu azalea, and not R. take a long time.-JoHN KNOWLTON, linearifolium var. macmsepalum, the NlaTine Villa, Warwick, Bernwda. name given P. 1. No. 199,302 in Frederic P. Lee's The Azalea Book (somewhere along the line there seems to have been a clerical error). In flower, the Luchu azalea is surely among the world's most handsome and dramatically beautiful Two Experiences with shrubs. Tree Peony Propagation 'When our family moved to a new Years ago, a nine year old plan t of house, the brave Luchu azaleas and Reine Elizabeth seemed so unhappy that made-up soil went with us. One was I transplanted it, setting it several inches planted in the garden on a mound with deeper than it had been growing. The a 4 by 4-foot sheet of aluminum beneath top died back. The following spring the to discourage unwanted invaders. The roots sent up eight shoots that made oth.er two went into a slathouse in raised quick growth. I tried layering the plant masonry beds. Then several indica type by the method used for gooseberries, azaleas were imported from Florida, a piling garden soil around and through dozen each of the clones 'George Lindley the clump, separating the shoots as Taber,' 'Formosa,' 'Southern Charm,' widely as possible without breaking, and and 'President Claeys.' They, too, went allowing only the tips to show above the into the slathouse in raised beds planted soil. After firming the soil I covered the in a fibrous marsh soil (with a low pH) mound with old burlap and kept it well which seemed worth trying. The pH watered all su mmer. A year later each was fine, but there was much osmunda shoot was well rooted, was cut off near fiber and precious little soil. Despite the ground, and was successfully planted. the use of appropriate fertilizers, none I realize that one experience does not of the plants inside the slathouse did pr·ove much. I feel sure that some well. For one thing, there was too little varieties will layer much more readily light. But the Luchu azalea atop the than others and that the same variety sheet of aluminum outside in the sun that may layer successfully in the sou th grew and flowered nicely. may not in the north. Even so, when Now came a lucky break. In a part of I read some of the reports of poor results a local marsh, which supports a scrubby with layering tree peonies I wonder mixed woodland of several acres, I final­ whether the gardener doing the report­ ly discovered just what I had been ing used mound layering or the type hoping to find:-a highly acidic organic that my neighbors speak of as laying soil, twelve inches of it above the water clown a branch. level of the marsh. Transplanted to this More recently I tried growing tree true soil in raised masonry beds built peonies from seed. Over a period of sev­ for me by a kind landlady, in sun out­ eral years I secured several hundred side the slathouse, the Luchu azaleas and seeds from five different sources. I shared most of the indicas came to life! These the seed with a gardener in Illinois and beds measured eighteen inches high with with a Kentucky neighbor because the a planting width of about three feet. At care I give seed is not a fair test. U nfor­ the bottom there is a thick layer of saw­ tunately, I kept no records, being sure at dust, then about ten inches of the marsh the time that I could not possibly forget soil protected by a sawdust mulch. A anything of so much interest. Of a hun­ little fertilizer has been used. dred seeels secured from one grower I At present, nearly two years from the think not one came up, though they were transplanting, all azaleas are doing well healthy looking seeds. Each of three other 182 THE AMERICAN HORTICULTURAL MAGAZINE

lots produced few seedlings. A lot of acerifolium to which it must be closely twenty seeds received packed in damp related. At any rate, with some pruning sphagnum and allegedly so packed as it makes a good subject for drought­ soon as removed from the seedpod gave troubled soils where a small plant is almost perfect germination. The seedlings needed. varied greatly in appearance and in ap­ A much larger and more vigorous spe­ parent strength. Many of them disap­ cies is V. semitomentosum that is said to peared before the second summer, pre­ grow in low ground from Florida to sumably leaving only the strongest. Re­ Texas, and up to Pennsylvania. This su J ts in Illinois and Kentucky were much one grows big, almost into a small tree, the same. Surprisingly enough, the seed but all I have grown I have managed to that I planted in late summer and never keep as a dense shrub by frequent prun­ saw again until I returned home in June ings. My plants are grown from cut­ produced fully as high a percentage of seedlings as the seed given conventional tings, as it roots easily, from a single care and attention. So far only two specimen in the woods near Gainesville, seedlings have flowered, and only one for Florida, and as yet I have not found it its second year. The interesting point in southern Alabama or west Florida, there is that the second year flowers were but without too serious searching.... much superior to the first year's flower The ubiquitous species here is V. nu­ in both form and size, suggesting that dum, present in almost every creek bot­ tree peonies may share the herbaceous tom. This, I think, is less ornamental peony's tendency toward variable bloom than the others but it seems to be accom­ during its first years.-MAuD R. JACOBS, panied by a variety that is very showy, South CaTTollton, Kentucky. one called angustifolium by Dr. Small, named for its narrower leaves. These are a dark shining green, and persistent. The plant itself has great possibilities in cultivation with its great masses of white flowers contrasted with the fine foliage. Southern Viburnums "Vhere a tree viburnum is wanted, Many garden enthusiasts in the Unit­ there is none better than V. ntfidulum. ed States are "taken" with the Genus This seems rare in these parts and with Vibumum and I am not an exception me is deciduous. My plant is only seven to this, collecting as many species as pos­ feet high but it is reported to grow to sible and growing them under garden twenty-five feet. conditions here on the northern Gulf I am especially enthusiastic about the Coast. species I have saved till the last because The familiar kinds need no introduc­ it would seem that certain of its char­ tion and very little comment in this ar­ acteristics offer great possibilities as an ticle. They are all fine ornamental ornamental. This is Vibun~um ovatum, plants which lend themselves beautifully sometimes called Walters viburnum. to the landscape planting plan: Vibur­ This species has tiny, bright shining num tinus for corners and portals, V. evergreen leaves, one-half to one inch in sus pensum where a more spreading plant size, obvate in shape with blunt teeth on is wanted, and V. japonicum where heavy the sides and wedge-shaped bases. If al­ texture is in order. For large buildings lowed to grow naturally, it becomes a there is V. odoratissimum to add to the thin-trunked twenty-foot tree, but if previous species, all from other coun­ sheared, it becomes a beautiful dense tries. broadleaf evergreen shrub strongly re­ The point of this note is to say some­ sembling some variety of Ilex cTenata, thing about the lesser kno'wn and appre­ but with opposite leaves. It apparently ci a ted native species. grows on the Atlantic seaboard and into One of these is a very small deciduous peninsular Florida and is said to reach type that inhabits wooded hillsides in its largest size in the Suwannee River west Florida and Alabama on the Coast­ Basin. My plants are seedlings from a al Plain. ]. K. Small calls this Vibumum tree, near Bradenton, Florida. Cuttings densifioTum, and its lobed maple-like root very easily.-E. ]. HORDER, Mobile, leaves make it look very much like V. Alabama. J ULY 1960. VOLUME 39, NUMBER 3 183

An enlarged leaf showing the flowen that resemble cate1-pillar legs.

S pathi;carpa sagitti folia

Spathicarpa sagittifolia, which has yellow-green fringe somewhat resem­ been rather aptly named the ca terpillar bling the legs of a caterpillar along the plant, is a very interesting greenhouse axis of the spathe. aroid from Brazil that should also do It h as not been observed to set seed well as a houseplant. Although its inflor­ in the gree n-house, although the plan t escences are not showy, they are attrac­ grows steadily, sending up new shoots tive and the plant's habit of fl owering from the underground crown, and ca n continuously is a strong point in its be divided with the utmost ease. SPa ­ favor. thicaTpa is not exacting as to soil require­ ments, doing well in any good potting The glossy green, arrowhead-sh aped soil that is kept moist. It seems, how­ leaves stand but three to fo ur inches in ever, to do bes t in pure sphagnum which h eight and are surmounted by the in­ is not allowed to dry out. A nigh t tem­ fl orescences, seven to eight inch es h igh, perature of sixty degrees F ahrenheit and consisting of narrow light-green spa thes a day temperature of seventy seem to be to which the spadix is completely fused. optimum.-D. G. H UTTLESTON, Long­ T hus the tin y, petal-l ess fl owers form a wood Gardens, Kennett Square, Penna. 184 THE AMERICAN HORTICULTURAL MAGAZINE

New Guinea Trumpet-Creeper seventy-five to eighty degrees Fahrenheit. Observations made under glasshouse During lVlarch, 1960, Longwood Gar­ dens flowered for the first time in this conditions at the Botanic Gardens at country a beautiful bignoniaceous vine, Adelaide, South Australia, where the Tecomanthe venusta, a new introduction plant has also been successfully grown into the Americas (P.I. 253223) having since 1952, indicate that this species is been obtained as a result of the fourth on the tender side and may require win­ cooperative Longwood Gardens-U.S.D.A. ter protection under subtropical or warm exploration for ornamentals, conducted temperate conditions. At the Botanic in Australia during 1958-1959. [See The Garden at Brisbane, Queensland (lati­ Nat. R OTt. iVJag. 38: 164-167. July, 1959.] tude approximately 27 ° south latitude, For want of a comon name and to indi­ or the equivalent of Miami, Florida, cate its p lace of origin, T ecomanthe with 27 ° north latitude) where this spe­ venusta is being called the New Guinea cies has been grown outdoors, Teeo­ Trumpet-Creeper. manthe venusta is perfectly hardy. On the basis of these Australian records, the A native of Australian New Guinea, vine is recommended for trial outdoors T ecomanthe venusta is a vigorous woody in subtropical Florida, throughout the dextrorse vine, under native conditions "West Indies and tropical America and probably climbing high into the tops o[ forest trees. Although its dark-green. in H awaii. Where occasional frosts compound (five leaflets) leaves are at­ are to be expected, it has been suggested tractive, the main ornamental feature of th ~ t the New Guinea Trumpet-Creeper the plant lies in the beautiful, pendant, mIght be grown successfully in pots, be­ ing moved outdoors during the warm tr~mpet-shaped ~owers which appear in axIlla!y, umbel-lIke clusters (up to six­ season and under some protection dur­ ing the winter. This procedure has been teen 111 a cluster on our specimen) Oil the old wood of the climbing stems. The effective in the Botanic Garden at Ade­ tubular flowers are a light mao-enta-rose laide where an annual top dressing has on the ~)U tside of the tu be (~loses t to been sufficient to keep plants in top RHS Sp1l1el Red 0023) fading to a paler growing and flowering condition. ~ose (0023/3) and creamy-yellow on the The Longwood Gardens' material of mne.r s~rfaces of the spreading lobes and T ecomanthe venusta was collected as the mSIde of the tube, which also sports cuttings by the writer in October, 1958, numerous narrow lines of Spinel Red from plants growing at the Botanic Gar­ running down to its base. Maximum den, Brisbane, Queensland, Australia. over-all length of the individual flowers Original plants cultivated in Australia is about three and a half inches and each were grown from propagations obtained is about tW? inches across the flaring, [rom the Department of Forests at Lae, somewhat Irregular lobes. Although New Guinea. A first account of the cul­ abundant nectar is produced at the base ture of the New Guinea Trumpet-Creep­ of each tube, the flowers are without ap­ er in Australia appeared in the Journal parent fragrance. Flower production on of th e Royal R01,ticultural Society I?l~n ts gr.own from rooted cu ttings is [T. R. N. Lothian, Tecomanthe dendro- faIrly rapId. At Longwood Gardens such 1Jhila, Jour. Royal R01-t. Soc. LXXXIII, plants produced flowers in about a year's Pt. 7, July, 1958], under the name Teco­ time. The first clusters to bloom ap­ man the dendrophila. Comparison of liv­ peared in early March, 1960, on the stem ing plants grown at the Botanic Garden only a few inches above ground level, and a t Brisbane and at Longwood Gardens s ubsequ e n~ blooming proceeded up the indicates that the species in culture is woody ma1l1 stem to a height o[ fifteen not Tecomanthe dend1'Ophila but rather feet or more from the ground. Under Tecomanthe venusta, as herein described. glass house conditions, it appears that the Confirmation of this identification has full flowering season may extend [rom come through the courtesy of Australian three to four weeks. colleagues and in particular H. W. Caul­ ~ecomanthe venusta appears to be field , Curator of the Garden at Brisbane, easIly propagated from simple three­ and S. Blake, Queensland Government node hardwood cuttings rooted in stand­ Botanist. - W. H. HODGE, Longwood ard media at optimum temperatures of Gm'dens, K ennett Squa1'e, Pennsylvania. LILIAN A. GUERNSEY

Styrax obassia