A synopsis of the Lemnaceae

C. den Hartog and F. van der Plas

Summary

The family Lemnaceae is divided into 2 subfamilies, with the genera and —

Lemna — the latter with 2 subgenera, and Staurogeton and Wolffioideae with the genera Wolffia, Wolffiella,

Wolffiopsis, and Pseudowolffia, the last two being new and based on former infrageneric taxa. All these

their taxa are described, and types indicated; keys are provided for their distinction.

listed with their few reduced. There Recognized species names are synonyms, a being newly are 5 new A of is excluded specific combinations. list invalid and dubious names added. The names are listed separately. An is in is explanatory glossary given ofthe terminologyused the descriptions, and illustrated by some diagrams (fig. 1).

Introduction

The Lemnaceae is well-defined and its delineation has diffi- a family never given any The of the within the has been elaborated culty. systematic arrangement genera family

by Schleiden (Linnaea 13, 1839, p. 385—392; Beitr. Bot. 1, 1844, p. 229—235) and later

by Hegelmaier (Lemnac., 1868, p. 1—169; Bot. Jahrb. 21, 1895, p. 268—305). In his last work Hegelmaier recognized 4 genera: Spirodela, Lemna, Wolffia, and Wolffiella. Hegel- work has been almost for the fact maier's accepted generally, except that most British

Bentham & Hooker authors, following (Gen. Pi. 3, 1881, p. 1000—1001) have not

In since recognized Spirodela as an independent genus. the years the publication of Hegel- of the has increased maier's work knowledge Lemnaceae considerably. Several new species have been described and and material has become available of flowering fruiting quite a number of species.

The need for a new critical revision of the family has been felt for some time, not in the least by physiologists who use these small, readily multiplying more and more for their experiments (Hillman, Bot. Rev. 27, 1961, p. 221—287). Recently Daubs (Monogr. in 'a Lemnac., 1965, p. 1—118) published a monograph of the Lemnaceae, order to give critical review of the family in the light of this later knowledge'. Unfortunately this work does the which from not meet requirements can be reasonably demanded a mono- and it well received American graph. consequently was not very (reviews by Howard, Clark Sida and Scientist 54, 1966, p. 242A—243A; & Thieret, 2, 1966, p. 437—438, it examine den Hartog, Blumea 15, 1967, p. 575—576). However, certainly inspired us to of within the and critically the status the various genera family, not to take anything for granted.

The results of our studies are with those of taxonomic only partly in agreement the with the earlier authors. We agree division of the Lemnaceae into 2 subfamilies, the Lem-

viz. Lemna noideae and the Wolffioideae. Within the Lemnoideae we recognize 2 genera, and Spirodela, as most other authors have done before. In the subfamily Wolffioideae,

viz. however, we recognize 4 genera, Wolffia, Wolffiella, Pseudowolffia, and Wolffiopsis.

The last-mentioned are the of 2 genera newly described; in original system Hegelmaier BLUMEA No. 356 VOL. XVIII, 2, 1970

Lemnaceae. — A-B. Fig. 1. Diagrams showing the external morphology of Spirodelapolyrhiza (L.) Schlei-

A. den; dorsal side of the frond,B. ventral side of the frond. — C. Wolffia sp. (a. stipe; b. budding pouch;

d. h. c. node; young frond showing the dorsal scale; e. ventral scale; f. primary root; g. secondary root; i. with male and female root sheath; root cap; j. flowering cavity flower).

they figure as sections or subsections. In our opinion they are sufficiently distinct to be

regarded as separate genera.

this the taxa above the rank of are described. Under each In paper only species genus

or subgenus description an annotated list of the species with their full synonymy is given.

TERMINOLOGY

The Lemnaceae are morphologically very reduced plants, and consequently the terms of the least used in the descriptions various taxa are, at partly, rather different from those the of familiar generally used for description more looking angiosperms. Therefore, for

the sake of convenience we have added a list of terms generally used for the description

of Lemnaceae, and some diagrams (fig. i). In this paper these terms are used exclusively

for descriptive purposes.

lacunous under the Air spaces. Large spaces epidermis, filled with gas (or water).

Budding pouch. The basal cavity in the Wolffioideae and the two lateral pockets in the Lemnoideae called here the fronds the are budding pouches, as young are produced. In

Lemnoideae one of the two pouches can also give rise to an inflorescence and is then

often called a The of the reproductive pouch. budding pouch Wolffioideae never pro-

duces an inflorescence.

Dorsal scale. A small, almost round, membranous scale at the base of the dorsal side of a

young frond of Spirodela, disappearing with age. F. A Lemnaceae C. den Hartog & van DER Plas: synopsis of the 357

Druses. Asteroid crystals of Ca-oxalate in the parenchyma of Spirodela.

Flowering cavity. A dorsal cavity in the frond of the Wolffioideae in which the inflorescence

is formed. This cavity is formed just before the frond flowers.

Frond. A single of a Lemnacea.

Node. Point on the frond from which the roots descend. One vascular bundle connects

the the from node stipe with node; the I or more nerves proceed towards the apex. Petiole. See stipe.

cells. to Solereder & Anat. Monokot. Pigment According Meyer (System. 3, 1928, p. the brown cells cells and the red 170—175) pigment are myriophyllin pigment cells contain anthocyanin.

Roots which the ventral scale and whose sheaths Primary roots. perforate are grown

together with that scale. Theseroots are appearing at an earlier stagein the development the frond than visible in of the secondary roots, and are already very young fronds (Spirodela).

Prophyllum. See ventral scale.

Raphides. Needle-like crystals of Ca-oxalate arranged in bundles (Lemnoideae).

Reproductive pouch. See budding pouch.

A frond of Resting bud. consisting a very compact tissue, filled with reserve food, sinking

to the bottom in winter and rising to the surface in spring (winter bud!). In temporary kind ofbuds the waters the same are formed, enabling the species to survive dry period. The turion of Spirodela is a special form of a resting bud.

sheath the of Root cap. A cylindrical membranous surrounding tip the root, cohering of the with the root sheath at an early stage in the development root.

Root scale. See ventral scale.

Root sheath. A cylindrical membranous sheath surrounding the base of the root, cohering

with the at the ofthe the the root cap an early stage in development root. As root grows

two parts become separated.

Secondary roots. Roots which do not perforate the ventral scale, their sheaths are covered scale by this but are never connate with it. These roots appear at a later stage in the

development of the frond than the primary roots (Spirodela).

Stalk. See stipe. stolon-like which the attached the mother Stipe. A structure by young plant is to plant.

It is often fugacious. Although it is certainly not homologous with the stalk of a leaf

it is often referred to as a petiole.

Turion (in ). A young frond differing from normal fronds by its thicker habit and with The more compact tissue filled reserve food. dorsal as well as

the ventral scale and In it sinks the some root primordia are present. autumn to bottom, and the surface in spring it rises to again. of Ventral scale. A scale at the ventral side of the frondof Spirodela, covering the bases the with secondary roots and/or grown together the root sheaths of the primary roots.

Winter bud. See resting bud.

LEMNACEAE

Monoecious, very rarely dioecious, small to minute aquatic annuals, floating at the surface of the of water, or floating just below the surface whereby only a very small part the frond is exposed to the air, or completely submerged and then rising to the surface in the small short flowering period. Fronds either solitary or connected in groups by hyaline flat or rarely elongate green stipes, symmetric or asymmetric, or inflated, ranging in 358 BLUMEA VOL. XVIII, No. 2, 1970

shape from reniform, round, elliptic, lanceolate, and linear to globose, green, with or red brown with both of without or pigment cells, sometimes types pigment. Roots when there is there is several, one, or none. Budding pouches I or 2; one budding pouch this inflorescence one flowering cavity and in a spatheless is borne (an exception is Wolffi- has when there of these opsis which 2 flowering cavities); are 2 budding pouches one gives rise to an inflorescence surrounded by a spathe. Inflorescence consisting of i female

male flowers. of anther and i or 2 Perianth none. Male flower consisting a single stamen; uni- or bilocular. Femaleflower inserted above the male fiower(s), consisting of I sessile,

unilocular with a short Ovula a seeded utricle. globular, ovary style. 1—4. Fruit 1—4

Seeds ribbed or smooth.

KEY TO THE SUBFAMILIES

Roots lateral, of axis. I. present. Buddingpouches 2, basal, oneoneither side the Inflorescence 1,developing from the one of budding pouches, consisting of 1 female and 2 male flowers enclosed by a membranous

spathe. Anther bilocular, transversely dehiscent. Raphides present Lemnoideae rise 1. Roots none. Budding pouch 1, basal, median, never giving to an inflorescence. Inflorescence 1

Anther (rarely 2), dorsal, consisting ofa cavity containing1 female and 1 male flower, without a spathe.

unilocular, apically dehiscent. Raphides none Wolffioideae

SUBFAMILY LEMNOIDEAE

Smallwater plants, floating at the surface or sometimes completely submerged in which case they come to the surface only in the flowering period. Fronds reniform, round, with without red cells the elliptic, obovate, or lanceolate; or pigment in epidermis; cells the the dorsal side raphides and often brown pigment in parenchyma; stomata on ofthe absent floating plants, in submerged plants; nerves I—15. Stipe hyaline, fugacious, and rarely green persistent. Dorsal and ventral scales present (Spirodela) or absent (Lemna).

—18 with root and with a root sheath. Roots 1 (rarely absent), a cap usually Budding either side of the in pouches 2, basal, lateral, one on axis, dorso-ventrally flattened, outline more or less triangular, opening by a transverse slit. Inflorescence I, lateral, developing of from one of the budding pouches, consisting I femaleand 2 male flowers enclosed by a membranous spathe. Male flower: anther bilocular, transversely dehiscent. Female flower Ovula superior and lateral to the 2 male flowers; style partly persistent. I—4, amphi- less tropous, anatropous,or orthotropous. Fruit globular or more or compressed, slightly ribbed. or distinctly winged. Seed smooth or longitudinally

KEY TO THE GENERA

Fronds with dorsal and ventral and attached. I. a a scale, I—many roots 3 —15 nerves. Stipe ventrally Brown pigment cells and druses in the parenchyma I. Spirodela

1. Fronds without dorsal and ventral scales, with 1 root (rarely none) and 1—3, often indistinct nerves.

Brown Lemna Stipe marginally attached. pigment cells and druses absent 2.

1. SPIRODELA

den Schleid., Linnaea 13 (1839) 391 (nom. gen. cons, prop.); Hartog, Taxon 19 (1970)

647—648. — LenticulariaSeguier, Pi. Veron. 3 (1754) 129. — Lemna sect. Spirodela Coss. &

Germ., Fl. Env. Paris 2 (1845) 577. — Lemna subgen. Spirodela Peterm., Deutschl. Fl.

(1849) 540. Type species: Spirodela polyrhiza (L.) Schleid. Small the either water plants, floating at surface. Fronds solitary or connected in groups C. Hartog & F. den van DER Plas: A synopsis of the Lemnaceae 359

reniform flat of 2 —5 (sometimes even more), symmetric or asymmetric, to obovate, or distinctly inflated, underside often red due to pigment cells in the epidermis; brown

in pigment cells, raphides, and druses the parenchyma; stomata on the dorsal side; margin entire; nerves 3—15. Stipe hyaline, fugacious, short or relatively long, attached to the underside of the frond. Dorsal scale present, fugacious in older plants. Ventral scale broad,

Roots less often pigmented. I—18, more or vascularized; root sheaths short, clustered together and covered by the ventral scale with which some of them are adnate, one or

this more roots perforating scale; root cap straight or slightly curved, acute or rarely the obtuse. Slit of budding pouch ventral to marginof the frond. Ovary with I amphitropous ovulum or 2 —4 anatropous ovula. Fruit asymmetric. the Notes: Schleiden, I.e., separated genus Spirodela fromLemna on the grounds of the the of occurrence of a dorsal and a ventral scale, conspicuous development spiral vascula, and the clearly recognizable nodes with many roots. In his opinion these characters were dieser der 'in Gruppe allereinfachsten Pflanzen gewiss Momente, bedeutsam genug um die Auf- Genus maintainedthe the stellung eines eignen zu rechtfertigen'. Hegelmaier genus on same

Lemna grounds, as he found no differences between the inflorescences of and Spirodela botanists have (Hegelmaier, Bot. Zeit. 29, 1871, p. 621—629, 645—666). In practice only the of numberof the and used character the roots to distinguish two genera, according to has the Daubs (Monogr. Lemnac., 1965, p. 8) 'no one seriously questioned generic status of establishment Schleiden'. Daubs Spirodela since its by stated that 'the greater size and complexity of the plant body of Spirodela, including its increased vascularization, larger number number of roots, tendency toward a plural of ovules, and the monosporic of development the embryo sac (in S. polyrhiza) are sufficient to regard Spirodela as distinct fromLemna’? with the value of the char- We disagree respect to taxonomie new Daubs. The size of acters put forward by the frond is certainly not a generic character:

S. punctata is exactly the same size as Lemna minor and L. perpusilla, and is considerably than it towards smaller L. trisulca. Although can be observed, a tendency an increasing

ofovula be a number can never generic character. Not all the Spirodela species have more than one ovulum, and in Lemna gibba and L. disperma there is generally more than one ovulum. Finally the monosporic development of the embryo sac, which has beenobserved in S. Maheswari be used polyrhiza by (Nature 181, 1958, p. 1745—1746) cannot as a taxonomic character before similar observations have been made in other Spirodela species, in particular in S. punctata.

The genus Spirodela can be subdivided into 2 species groups; Hegelmaier (Lemnac., Bot. these 1868, p. 147—152; Jahrb. 21, 1895, P- 283—288) distinguished as ‘Typus der and der The first mentioned has S. polyrhiza’ ‘Typus S. oligorrhiza ’. ‘Typus’ 5 —12 mm fronds and well ' long primary as as secondary roots. The other ‘Typus’ has 2—5 mm long fronds and primary roots only; its habit is very similar to that of Lemna. The differences between these two species groups are in our opinion too insignificant to regard them as separate sections. Nomenclature: Farwell Midi. foot (Amer. Natur. 12, 1931, p. 239, in note) questioned for the correctness ofthe name Spirodela the genus. According to him Lenticula Hill (1757) is the correct name. Indeed Hill's work contains a rather extensive description of Lenti- cula major (= Spirodela polyrhiza), and the two other species L. vulgaris (= Lemna minor) the andL. aquatica trisulca (= Lemna trisulca) are classified in genus without much comment.

to Mansfeld clear that According (Fedde Repert. 45, 1938, p. 58), however, it is quite Hill's ofLenticula and Linne's ofLemna conception conception are the same, as the species the composition of two genera was almost identical. As Hill did nomenclature his and not accept binary specific names are invalid, no 360 BLUMEA VOL. XVIII, No. 2, 1970

in nomenclatural type can be indicated. The first valid combinations the genus, Lenticula

L. in If first of is minor and trisulca, were published by Scopoli 1772. the these accepted as

the of the the can be reduced a nomenclatural type species genus Lenticula, genus as

of L. synonym Lemna

This reasoning cannot be applied to the generic name Lenticularia Seguier (1754).

Siguier's diagnosis matches Spirodela, and, therefore, Lenticularia has to be regarded as

this it an earlier name for genus. This has nomenclatural consequences and, therefore, that the has been proposed name Spirodela should be conserved in preference to Lenticu-

laria (den Hartog, Taxon, 19, 1970, p. 647—648).

Distribution: The genus is widely distributed in the temperate and tropical zones of both hemispheres.

1. Spirodela polyrhiza (L.) Schleid., Linnaea 13 (1839) 392. — Lemna polyrhiza L.,

Pi. — Herb. Sp. ed. 1 (1753) 970 [Lenticula major Hill, Brit. (1757) 531, nomen invalidum.]

— Lenticula Fl. Fr. —Lemna orbicularis Kitaibel J polyrhiza Lamk., 2 (1778) 189. ex Schultes,

Oesterr. Fl. ed. seminudum. — Lemna thermalis 2, 1 (1814) 64, nomen Beauv., J. Phys.

82 — Chim. Hist. Nat. (1816) 102, 113, £23; Nuttall, Gen. Amer. I (1818) 19. Lemna

orbiculata Roxb., [Hort. Beng. (1814) 66, nomen] Fl. Ind. 3 (1832) 565. — Telmatophace

Fl. ibid. ed. — polyrhiza Godr., Lorr. ed. x, 3 (1843) 18; 2, 2 (1857) 327. Lemna major [C. A. Ind. Pi. Meyer, Cauc. (1831) 11, nomen] Griff., Not. 3 (1851) 216; Ic. As. 3 (1851): pi. 264.

— Telmatophace orbicularis Schur, Enum. Pi. Transs. (1866) 635. — Spirodela atropurpurea Guide Blatter Ind. Montand., Bot. (1868) 309. — Lemna maxima & Hallb., J. Bot. 2 (1921)

49. — Spirodela maxima McCann, J. Bombay Nat. Hist. Soc. 43 (1942) 158. — Spirodela

masonii polyrhiza var. Daubs, Monogr. Lemnac. 34 (1965) 13.

It is not impossible that Lemna thermalis is an earlier name for Spirodela biperforata

Koch. Although Beauvois mentioned several differences between Lemna thermalis and

L. he information about characters used for polyrhiza gave no nowadays distinguishing between the of The of themalisneeds species Spirodela. type L. reinvestigation.

intermedia 2. Spirodela W. Koch, Ber. Schweiz. Bot. Ges. 41 (1932) 114.

3. Spirodela biperforata W. Koch, Ber. Schweiz. Bot. Ges. 42 (1933) 188 needfurther Both Spirodela intermedia and S. biperforata examination. species are closely

related to S. polyrhiza.

Gard. 4. Spirodela punctata(G. F. W. Meyer) Thompson, Rep. Mo. Bot. 9 (1897) 28.

— Lemna punctata G. F. W. Meyer in Prim. Fl. Esseq. (1818) 262. — Lemna oligorrhiza

Linn. Soc. — Lemna melanorrhiza F. M. Bot. Kurz, J. Lond. 9 (1866) 267. v. ex Kurz, J.

— ibid. — 5 (1867) 115. Lemna pleiorrhiza F. v. M. ex Kurz, 5 (1867) 115. Spirodela oligorrhi-

za inch ß melanorrhiza Hegelm., Lemnac. (1868) 147—150, var. Hegelm., var. γ pusilla

Hegelm., var. δ pleiorrhiza Hegelm., and var. Є javanica Hegelm. — Spirodela melanorrhiza

Hegelm., Bot. Jahrb. 21 (1895) 287. — Spirodela pusilla Hegelm., ibid. 21 (1895) 287). —

Spirodela pleiorrhiza Hegelm., ibid. 21 (1895) 288. — Spirodela javanica Hegelm., ibid. 21

(1895) 288.

2. LEMNA

Pi. ed. — Lenticula Herb. L., Sp. Pi. ed. 1 (1753) 970; Gen. 5 (1754) 417. [Hill, Brit. (1757)

Boehmer in Def. Pi. Mich, [530 Ludwig, Gen. (1760) 499; ex Adans., Fam. 2 (1763) 471.

— Hydrophace Hall., Hist. Stirp. Indig. Helv. 3 (1768) 68. — Telmatophace Schleid., Lin- Lemiiaceae C. den Hahtog & F. van der Plas: A synopsis of the 361

— naea 13 (1839) 391. Staurogeton Rchb., [Consp. (1828) 288, nomen] Nom. (1841) 33. —

Lenticularia Guide non Pi. Montandon, Bot. (1868) 308, Seguier, Veron. 3 (1754) 129. Type species: Lemna minor L.

Small water plants, floating at the surface or sometimes completely submerged in the which case they come to the surface only in flowering period. Fronds either solitary

connected of to or in groups 2 —10 (sometimes even more), symmetric slightly asymmet- ric, round, elliptic, oblong, obovate, or lanceolate, flat or slightly swollen, sometimes

with median of the considerably inflated, often a row papillae on dorsal side; with or without red pigment cells in the epidermis; raphides in the parenchyma; brown pigment cells the none; druses none; stomata on dorsal side of floating plants, but absent in the sub- merged plants; margin entire, rarely denticulate; nerves 1—3(—5). Stipe hyaline and fuga- attached the Dorsal cious or green and persistent, to margin. as well as ventral scale absent.

Root I (rarely absent), slightly vascularized, with or without a distinct root sheath; root cap straight or curved, obtuse, mucronate, or acute. Slit of budding pouch coinciding with the margin of the frond, rarely ventral or dorsal to the margin. Flowering proterandric, proterogynic, or simultaneous. Ovary with I orthotropous or amphitropous ovulum or with 2 —4 anatropous ovula. Fruit symmetric or asymmetric. Seeds longitudinally ribbed, rarely smooth.

literature have been referred as of the Note: hi two species to type genus Lemna. In the & ed. works of Britton Brown (111. Fl. North. U.S. 2, 1913, p. 447), Britton (Fl.

Bermuda, 1918, p. 61), Britton & Millspaugh (Bahama Fl., 1920, p. 62), and Britton &

8c has been Wilson (Sc. Surv. P. Rico Virgin Isl. 5, 1923, p. 131) Lemna trisulca L. indi- cated such without comment. Hitchcock & as Green (Int. Bot. Congr. Cambridge, 1930.

as the because 'one Nom. Prop., 1929, p. 187) proposed L. minor type species it is of the and the best known of the original species, only one of them placed by Engler in section

Eulemna’. However, both proposals do not satisfy the directives for designating a lecto-

the Code of type as given in International Botanical Nomenclature (1966, p. 71). The for Lemna trisulca the has that it is the first reason choosing as type species possibly been

ofLemna mentioned within the species by Linne, as it is in a rather isolated position genus.

The Code warns against this procedure as being unscientific and a possible cause for confusion.

The Hitchcock Green arguments brought forward by & in favour ofLemna minor as

of the are based on the later of type species genus obviously application the name. Fortu- nately the generic diagnosis of Linne (Gen. Pi. ed. 5, 1754, p. 417) contains the phrase

‘monophyllus, subrotundus which can be applied to Lemna but not to L. trisulca. ’, minor,

this favour of as the of For reason we are in L.i minor being regarded type species Lemna. divided the : In 1868 Hegelmaier genus Lemna into 2 subgenera, Hydrophace and Telmatophace, the latter subgenus containing only L. gibba. The subgenus Hydrophace with the was divided into 2 sections, Staurogeton, only species L. trisulca, and Eulemna. latter Within the section 3 species groups were recognized, viz. the Lemna valdiviana the and the reduced group, L. perpusilla group, L. minor group. In 1895 Hegelmaier of Telmatophace to the rank section, following Cosson & Germain (1845), and at the same he the the thus time raised species groups to same rank, recognizing 5 sections, viz. sect.

Telmatophace, sect. Lemna, sect. Staurogeton, sect. Alatae (for the L. perpusilla group), the and sect. Uninerves (for L. valdiviana group). Later authors didnot follow Hegelmaire's of the subdivision genus Lemna. We too do not see the need for such an excessive splitting of small in it a genus. However, our opinion seems fully justified on morphological grounds to recognize Staurogeton as a separate subgenus. The status of Telmatophace is still under investigation.

Distribution: The genus is almost cosmopolitan. BLUMEA VOL. No. 362 XVIII, 2, 1970

KEY TO THE SUBGENERA

I. Floating water plants. Fronds round, elliptic, oblong, or obovate, with i root. Slit of budding pouch

coinciding with the margin of the frond or ventral to the margin subgen. Lemna

i. Submerged water plants, only rising to the surface in the flowering period. Fronds oblong to linear- of of lanceolate, with or without a root. Slit budding pouch just dorsal to the margin the frond subgen. Staurogcton

Subgen. LEMNA

Hydrophace Hall., Hist. Stirp. Indig. Helv. 3 (1768) 68. — Lemna sect. Hydrophace Dumor-

Fl. — Horkel: tier, Belg. (1827) 166. Lemna subgen. Wolfia auct., non Endl., Gen. Pi.

(1837) 232, — Telmatophace Schleid., Linnaea 13 (1839) 391 — Lemna sect. Telmatophace

Coss. & Germ. Fl. Env. Paris 2 (1845) 576. — Lemna subgen. Telmatophace Peterm.,

Deutschi. Fl. (1849) 54°» P-P- — Lemna subgen. Hydrophace sect. Eulemna Hegelm., Lemnac.

(1868) 135.

Small water plants, floating at the surface. Fronds symmetric or slightly asymmetric,

round, elliptic, oblong, or obovate, flat to conspicuously swollen, with or without red

pigment cells in the epidermis; stomata on the dorsal side; margin entire; nerves I—3(—5), indistinct. and with distinct sometimes Stipe hyaline fugacious. Root 1, always present, a root sheath. Slit of budding pouch coinciding with the margin of the frond, rarely ventral to the with margin. Ovary 1 amphitropous or orthotropous ovulum or with 2—4 anatropous ovula.

Pi. ed. — Pi. I. Lemnaminor L., Sp. 1 (1753) 970. [Lenticula palustris Garsault, Fig. Anim.

Anim. — Med. (1764) t. 336; Descr. Pi. (1767) 206, nomen invalidum.] Lenticula minor ed. Lenticula Herb. Scop. Fl. Cam. 2,2 (1772) 213. — vulgaris [Hill, Brit. (1757) 531,

nomen invalidum] Lamk, Fl. Fr. 2 (1778) 189. — Lemna vulgaris Lamk, Encycl. 3 (1792)

— minima Chim. 82 — 464. Lemna Thuiller ex Beauvois, J. Phys. Hist. Nat. (1816) 113.

Fl. Paris — Lenticularia monorhiza Lemna minor var. minima Chev., 2 (1827) 256. Montand.,

Guide — Fl. Bot. (1868) 308. Hydrophace minor Bubani, Pyren. 4 (1897) 23.

Nearly all records ofLemna minor from tropical and subtropical regions relate in fact to

L. perpusilla.

Pi. ed. Lenticula Fl. 2. Lemna gibba L., Sp. 1 (1753) 970. — vulgaris var. f} Lamk, Fr.

— — Lenticula 2 (1778) 189. Lemna vulgaris var. a Lamk, Encycl. 3 (1792) 464. gibba

Meth. — Lenticula Fl. — Moench, (1794) 319. gibbosa Renault, Dep. Ome (1804) 40.

Telmatophace gibba Schleid., Linnaea 13 (1839) 391. — Telmatophace gibbosa Montand.,

Guide Bot. (1868) 308. — Lemna cordata Sesse & Moc., Pi. N. Hispan. La Naturaleze Pi. ed. ser. II, i, App. (1890) 159; N. Hispan. 2 (1893) 147.

In its typical form Lemna gibba is a very characteristic species; flat forms of this species,

however, can be easily mistaken for L. minor. Further it is not at all certain that all flat

‘L. form ofthis The is still gibba’ truly represent a species. species under investigation. For

further data on this 'flat form' referred Sloover one is to De (Natur. Belg. 47, 1966, p. Lond. den 443 —456), Guppy (J. Linn. Soc. 30, 1894, p. 323 —330), Hartog (Gorteria 4,

& 1968, p. 90—92), deLange Segal (Gorteria 4,1968, p. 5 —12), and Mason(Fl. Marshes

California, 1957, p. 331).

Lemna Bot. Zeit. — Lemna 3. disperma Hegelm., 29 (1871) 654. disperma var. fallax

Hegelm., Bot. Jahrb. 21 (1895) 291. — Lemna parodiana Giardella, Notas Mus. La Plata

2, 12 (1937) 97—100. the for of L. disperma is name used Australian material this species, while L. parodiana C. den Hartog & F. van der Plas: A synopsis of the Lemnaceae 363

has been used for South American specimens. The taxonomieposition of this species in is relation to L. minor and L. gibba not yet clear. In some respects it seems an intermediate between these.

obscura — 4. Lemna (Austin) Daubs, Monogr. Lemnac. (1965) 20. Lemna minor var.

obscura ed. — Lemna minor Austin in A. Gray, Man.Bot. 5 (1867) 479. var. colorata Hegelm.,

Lemnac. (1868) 144.

This species needs reinvestigation. It is possible that it is only a growth-form ofL. gibba.

Fl. — 5. Lemna perpusilla Torrey, N.Y. 2 (1843) 245. Lemna aequinoctialis Welw., Conselho Apontam. phytogcogr. sobre a flora da prov. de Angola in Annaes do Ultram. Welw. Dec. 1858, nr. 55 (1859) 578. — Lemna angolensis ex Hegelm., J. Bot. 3 (1865) 112.

-Lemna perpusilla var. trinervis Austin in A. Gray, Man. Bot. ed. 5 (1867) 479. — Lemna

— membranacea paucicostata Hegelm., Lemnac. (1868) 139. Lemnapaucicostata var. Hegelm.,

— Fl. — Lemnac. (1868) 141. Lemna trinervis Small, SE. U.S. (1903) 230. Hydrophace

Midi. — Blatt. & perpusilla Lunell, Amer. Natur. 4 (1915) 237. Lemna minima Hallb., J.

Ind. Bot. 2 (1921) 50. — Lemna blatteri McCann, J. Bombay Nat. Hist. Soc. 43 (1942)

— eleanorae ibid. 153. Lemna McCann, 43 (1942) 154.

6. Lemna valdiviana Linnaea — Lemna minor Phil., 33 (1864) 239. var. cyclostasa Elliott,

Bot. S. Carol, and Georgia 2 (1824) 518. — Lemna torreyi Austin in A. Gray, Man. Bot.

ed. — Lemna valdiviana Lemnac. — 5 (1867) 479. var. pellucida Hegelm., (1868) 138.

Lemna valdesiana S. Watson in U.S. Geol. Expl. 40th parallel (cited in Ind. Kew. as Bot.

King's Exp.) (1871) 336; obviously a mis-spelling of L. valdiviana. -Lemna valdiviana

abbreviata in Fl. Bras. — Lemna var. Hegelm. Mart., 3,2 (1878) 19. valdiviana var. platy-

in — valdiviana clados Hegelm. Mart., Fl. Bras. 3,2 (1878) 19. Lemna var. robusta Hegelm.,

— Gard. Bot. Jahrb. 21 (1895) 298. Lemna cyclostasa Thompson, Rep. Mo. Bot. 9 (1897) 35.

minuscula Sudamer. 7. Lemna Herter, Rev. Bot. 9 (1954) 185. — Lemna minuta H., B.

& & Med. York K., Nov. Gen. Sp. 1 (1815) 372, non Rafin., Repos. N. 5 (1808) 353;

Pi. — Pi. Kunth, Syn. Aequin. 1 (1822) 136. [Lemna minima Kunth, Enum. 3 (1841) 5

(nomen in synon. sub L. minor, obviously a mis-spelling of L. minuta), non L. minima

82 Humb. Beauvois, J. Phys. Chim. Hist. Nat. (1816) 113; ex Phil., Linnaea 29 (1857) 45. ibid. valdiviana — Lemna nomen; 33 (1864) 239, nomen], var. minima Hegelm., Lemnac.

(1868) 138.

Bot. Gard. According to Thompson (Rep. Mo. 9, 1897, p. 135) Lemtia valdiviana var.

platyclados Hegelm. is a form of L. minuscula.

Subgen. STAUROGETON

Rchb. Fl. — Germ. 1 (1830) 10. Lemna sect. Hydrophylla Dumortier, Fl. Belg. (1827)

165. — Staurogeton Rchb., Consp. (1828) 288, nomen. — Lemna sect. Staurogeton Endl., Pi. Gen. Suppl. (1840) 1369. — Lemna subgen. Hydrophace sect. Staurogeton Hegelm.,

Lemnac. (1868) 133.

Type species: Lemna trisulca L. the when Fronds Small, submerged water plants, floating at surface only flowering.

less thin, more or symmetric, oblong to linear-lanceolate, entire or denticulate towards the without red apex, green, pigment cells, nerves I—3, sometimes indistinct; stomata the the on dorsal side in flowering period. Stipe persistent, hyaline and short or green 364 BLUMEA VOL. XVIII, No. 2, 1970

of and distinctly elongate. Root I, or absent; root sheath indistinct. Slit budding pouch just the of the frond. with dorsal to margin Ovary I amphitropous ovulum; fruit broad, less Seed ribbed. more or symmetric.

Pi. ed. trisulca 8. Lemna trisulca L., Sp. I (1753) 970. — [Lenticula aquatica Hill, Brit. ed. Herb. (1757) 531, nomen invalidum.] —Lenticula trisulca Scop., Fl. Cam. 2 (1772) 213.

— Lenticula ramosa Lamk. Fl. Fr. 2 (1778) 189. — Lemna cruciata Roxb., [Hort Beng.

(1814) 66, nomen] Fl. Ind. 3 (1832) 566. — Lemna intermedia Ruthe, Fl. Mark Brandenb.

und ed. — bisulca Pfl. Niederlausitz, 2 (1834) 277. Lemna C. A. Meyer in Beitr. Russ.

Reich — trisulcus Pi. — 9 (1854) 104. Staurogeton Schur, En. Transs. (1866) 636. Staurogeton trisulcum Montand., Guide Bot. (1868) 308. — Hydrophace trisulca Bubani, Fl. Pyren. 4

(1897) 23.

Lemna II 9. tenera Kurz, J. As. Soc. Bengal 40, (1871) 78.

SUBFAMILY WOLFFIOIDEAE

the Small to minute water plants, floating freely at surface, sometimes floating just surface small of frond is the below the whereby only a very part the exposed to air, or completely submerged in which case they come to the surface only in the flowering period. Fronds ranging in shape from linear, oblong, strap-like, broad elliptic, disc-shaped with without brown cells and to globular or ellipsoid; epidermis or pigment always without nerves none. Vascular absent for an occa- raphides; none; roots tissue except sional trace in the stamen. Dorsal and ventral scales none. Budding pouch basal, median, and well- either triangular, dorso-ventrally flattened, opening by a transverse slit with a circular with visible developed stipe, or funnel-shaped with a opening and a stipe not of to the naked eye. Inflorescence 1, rarely 2 (in Wolffiopsis), dorsal, consisting a cavity and without Male containing i female i male flower, a spathe. flower: anther unilocular, dehiscent along an apical pigmented line. Female flower situated nearer to the budding pouch than the male flower; style persistent; Ovulum I, orthotropous. Fruit globular or slightly compressed. Seed smooth.

KEY TO THE GENERA

i. Plants flat. Budding pouch triangular, dorso-ventrally flattened, opening by a transverse slit. Stipe well-developed.

2. Frond submerged, thin membranous, with brown pigment cells in the epidermis.

Frond falcate. 3. asymmetric, linear-oblong to almost strap-like, often Budding pouch asymmetric.

Stipe lateral, short or elongate. Inflorescence i 3. Wolffiella curled. 3. Frond symmetric, broad-elliptic to ovate, slightly Budding pouch symmetric. Stipe

median, short. Inflorescences 2 5. Wolffiopsis round without cells 2. Frond floating at the surface, slightly swollen, symmetric, or nearly so, pigment

in the epidermis. Buddingpouch symmetric. Stipe median, long, membranous,more or less widened.

Inflorescence 1 4. Pseudowolffia

Plants with circular visible 1. globularor ellipsoid. Buddingpouch funnel-shaped a opening. Stipe not to

6. the naked eye Wolffia

3. WOLFFIELLA

Hegelm., Bot. Jahrb. 21 (1895) 303. — Wolffia subgen. Wolffiella Hegelm., Lemnac.

(1868) 131. Type species: Wolffiella oblonga (Phil.) Hegelm. Hartog & Lemnaceae C. den F. van der Plas: A synopsis of the 365

Small basal of submerged water plants, only the parts the plants emerged when flower- ing. Fronds asymmetric, flat, thin membranous, linear-oblong to almost strap-like, often with with brown cells the falcate, air spaces, pigment in epidermis; stomata only present

in the emerged parts when flowering; margin entire or slightly toothed. Budding pouch

more or less asymmetric, triangular, dorso-ventrally flattened, opening by a transverse

a short lateral lateral the median slit, with or elongate stipe. Inflorescence i, to line, protero-

gynic. Fruit slightly compressed.

Note: We indicate propose to Wolffiella oblonga (Phil.) Hegelm. as the type species of the the the genus. Of 4 species placed by Hegelmaier in genus Wolffiella it is the best known.

Distribution: The genus occurs with 4 species in the tropical, subtropical, and warm- of fifth temperate areas America. A species is known from South Africa.

Wolffiella — 1. oblonga (Phil.) Hegelm., Bot. Jahrb. 21 (1895) 303. Lemna oblonga

— Phil., Linnaea 29 (1857) 45- Wolffia oblonga Hegelm., Lemnac. (1868) 131. — Wolffia Fl. lingulata var. minor Hegelm. in Mart., Bras. 3,2 (1878) 10.

Wolffiella — 2. lingulata (Hegelm.) Hegelm., Bot. Jahrb. 21 (1895) 303. Wolffi alingulata

Hegelm., Lemnac. (1868) 132.

3. Wolffiella gladiata (Hegelm.) Hegelm., Bot. Jahrb. 21 (1895) 304. — Wolffia gladiata

Hegelm., Lemnac. (1868) 133.

Wolffiellafloridana D. Smith) Thompson, Card. — 4. (J. Rep. Mo. Bot. 9 (1897) 37-

Bull. — Wolffia gladiata var. floridana J. D. Smith, Torr. Bot. Cl. 7 (1880) 64. [Wolffia

Smith ex floridana J. D. Hegelm., Bot. Jahrb. 21 (1895) 305 (not validly published)].

Wolffiella denticulata — 5. (Hegelm.) Hegelm., Bot. Jahrb. 21 (1895) 305. Wolffia denticulata Hegelm., Lemnac. (1868) 133.

4. PSEUDOWOLFFIAnov. gen.

Horkel Ord. Wolffia [ex Bartl., (1830) 76, nomen (‘Wolfia’)] ex Schleid., Linnaea 13

(1839) 389, non Horkel ex Schleid., Beitr. Bot. 1 (1844) 233; Kunth, Enum. Pi. 3 (1841) 4

Deutschl. Fl. — (‘Wolfia’). - Lemna subgen. Wolffia Peterm., (1849) 540. Wolffia sect. subsect. Lemnac. Uniflorae Stipitatae Hegelm., (1868) 122; Bot. Jahrb. 21 (1895) 300. der Type species: Pseudowolffia hyalina (Delile) den Hartog & van Plas.

Small water plants, floating at the surface. Fronds symmetric, slightly swollen, round with without cells the or nearly so, air spaces, pigment in epidermis; numerous stomata the less on dorsal side; margin entire or more or denticulate. Budding pouch symmetric,

triangular, dorso-ventrally flattened, opening by a transverse slit, with a long, membra- less median the nous, more or widened stipe on underside. Inflorescence I, lateral or almost

median, proterogynic. Fruit slightly compressed. The Nomenclature: genus Wolffia was originally typified by W. delilii (= W. hyalina).

This and the species W. repanda are so different from other species accomodated in that the division of the this would Wolffia genus into 2 separate genera is justified. As

of — cause a number name changes, even such well-known species as W. arrhiza and columbiana would be of the W. have renamed — has to a retypification genus Wolffia been this proposed (den Hartog, Taxon 18, 1969, p. 591—592). Although in proposal 366 BLUMEA VOL. XVIII, No. 2, 1970

that it is stated we share Monod's opinion that W. hyalina and W. repanda have to be these has accomodated in Wolffiella, a further study of species shown that they have a number of characters in which the erection of Pseudo- common justifies a new genus, wolffia.

Distribution: The is restricted northern and central genus to Africa, and contains 3 species.

den der — I. Pseudowolffia hyalina (Delile) Hartog & van Plas, nov. comb. Lemna

Fl. — delilii — hyalina Delile, Egypt. (1813) 75. Wolffia Schleid., Linnaea 13 (1839) 390.

Wolffia hyalina Hegelm., Lemnac. (1868) 128. — Wolffiella hyalina Monod, Mem. Soc. Afr. dedies Hist. Nat. Nord, hors ser. 2, Trav. Bot. a Rene Maire (1949) 242.

2. Pseudowolffiarepanda (Hegelm.) denHartog & van der Plas, nov. comb. — Wolffia

repanda Hegelm., J. Bot. 3 (1865) 113. — Wolffiella repanda Monod, Mem. Soc. Hist.

Nat. Afr. Nord, hors ser. 2, Trav. Bot. dedies a Rene Maire (1949) 242.

Pseudowolffia monodii den & van der comb. — 3. (Jovet-Ast) Hartog Plas, nov.

Wolffiella monodii Jovet-Ast, Bull. Inst. Fond. Afr. Noire 30 (1968) 837—844, f. 3.

WOLFFIOPSIS 5. non. gen.

Wolffia sect. Biflorae Hegelm., Lemnac. (1868) 130; Bot. Jahrb. 21 (1895) 300. Plas. Type species: Wolffiopsis welwitschii (Hegelm.) den Hartog & van der Small with small of base submerged water plants only a part the at the water surface.

Fronds thin with obtuse symmetric, flat, membranous, broad-elliptic to ovate, a very base and with the basal withbrown apex, entire, slightly curled, air spaces in part, pigment in in cells the epidermis; stomata very few or absent, only present the emerged part.

Budding pouch symmetric, triangular, dorso-ventrally flattened, opening by a transverse the of slit, with a short, median stipe on underside. Inflorescences 2, one on either side the median line, maleand female flowers flowering simultaneously. Fruit slightly compressed. and Distribution: Monotypic genus, distributed in tropical Africa tropical America.

welwitschii den der comb. — 1. Wolffiopsis (Hegelm.) Hartog & van Plas, nov.

— Welw. Wolffia welwitschii Hegelm., J. Bot. 3 (1865) 114. Wolffia conguensis ex Trimen,

J. Bot. 4 (1866) 223. — Wolffiella welwitschii Monod, Mém. Soc. Hist. Nat. Afr. Nord,

sér. ä Maire hors 2, Trav. Bot. dédiés Rene (1949) 229, 242. The the African and this problem whether American material of species are exactly identical needs further investigation.

6. WOLFFIA

Horkel Ord. [ex Bartl., (1830) 76, nomen (‘Wolfia’)] ex Schleid., Beitr. Bot. 1 (1844) 233

den 18 — Griff, ex (nom. gen. cons, prop.); Hartog, Taxon (1969) 591 —592. Grantia Voigt, Suburb. Calc. Billotia Hort. (1845) 692; Not. 3 (1851) 223. — Bruniera Franch., I (1864)

25, 30. — Wolffia sect. Uniflorae subsect. Estipitatae Hegelm., Lemnac. (1868) 122; Bot.

Jahrb. 21 (1895) 301. michelii Schleid, Lectotype species: Wolffia (typ. cons, prop.) surface. Fronds Small water plants, floating at the symmetric, thick, more or less globular, ellipsoid or ovoid, sometimes dorsally flattened, with fleshy parenchyma without Plas: C. den Hahtog & F. van der A synopsis of the Lemnaceae 367

air without brown cells in in spaces, with or pigment the epidermis; stomata the dorsal

of the or with a few or less part frond; margin entire more prominent papillae. Budding with circular and with pouch basal, funnel-shaped opening a rudimentary stipe (only

the Fruit visible after dissection under microscope). Inflorescence I, proterogynic. globular.

Seed globose or slightly compressed. Distribution: distributed the of The genus is widely in temperate and tropical zones with both hemispheres, at least 7 species.

Wolffia arrhiza — 1. (L.) Horkel ex Wimmer, Fl. Schles. ed. 3 (1857) I 4°- Lemna

arrhiza L., Mant. 2 (1771) 294. — Lenticula arrhiza Lamk. Fl. Fr. 2 (1778) 190. — Wolffia

michelii — delilii Schleid., Beitr. Bot. (1844) 233. Wolffia auct. non Schleid., 1839: Miq., Nederl. Kruidk. Arch. Fl. Ned. Ind. Linn. Soc. 3 (1855) 428; 3 (1855) 221; Kurz, J. Bot.

— Billotia — arrhiza 9 (1866) 265. Bruniera vivipara Franch., 1 (1864) 25. Telmatophace Fl. Berks. Schur, Enum. Pi. Transs. (1866) 635. — Horkelia arrhiza Druce, (1898) 511.

Var. australiana Austr. Benth., Fl. 7 (1878) 162, represents probably a new species This (see Eichler, Suppl. Fl. S. Austr., 1965, p. 78). is still under investigation.

Wolffia der — 2. globosa (Roxb.) den Hartog & van Plas, nov. comb. Lemna globosa Ind. Suburb. Fl. — Grantia Griff, Calc. Roxb., 3 (1832) 565. globosa ex Voigt, Hort.

— schleideni Nederl. Kruidk. Arch. (1845) 692; Not. 3 (1851) 229. Wolffia Miq., 3 (1855) Fl. Ned. — delilii schleideni 428; Ind. 3 (1855) 221. Wolffia var. Kurz, J. Linn. Soc. Bot. 9

(1866) 263. — Wolffia cylindracea Hegelm., Lemnac. (1868) 123.

3. Wolffia columbianaKarsten, Bot. Unters. 1 (1863) 103. — Grantia Columbiana Mac

— columbiana Mill., Metasp. Minn. (1892) 135. Bruniera Nieuwland, Amer. Midi. Natur. 2

(1912) 306.

Wolffia brasiliensis Ann. Sci. — 4. Weddell, Nat. Ill, 12 (1849) 170. Grantia brasiliensis

Mac Mill., Metasp. Mum. (1892) 134.

Wolffia Fl. Ind. — brasiliensis borealis 5. punctata Griseb., Br. W. (1864) 512. W. var.

Engelm. ex Hegelm., Lemnac. (1868) 127. — Bruniera punctata Nieuwland, Amer. Midi.

Natur. 2 (1912) 306.

6. Wolffia papulifera Thompson, Rep. Mo. Bot. Gard. 9 (1897) 40

Wolffia Linn. — Grantia 7. microscopica (Griff) Kurz, J. Soc. Bot. 9 (1866) 265.

Griff ex Suburb. Calc. microscopica Voigt, Hort. (1845) 692; Not. 3 (1851) 226.

INVALID AND DUBIOUS NAMES

Horkelia See Rchb., Consp. (1828) 44, nomen = Wolffia Horkel ex Schleid. Bartl., Ord. (1830) 76.

monorrhiza Hall, Fl. ed. sub Lenticula = Hydrophace ex Scop., Carn. 2 (1772) 213, nomenin synon. minor Scop. Lemna minor L.

Lemna bannatica Waldst. Kitaibel Linnaea in sub & ex Schleid., 13 (1839) 392, nomen synon. Spirodela polyrhiza (L.) Schleid.

Lemna cherokensis Schweinitz ex Hegelm., Bot. Jahrb. 21 (1895) 297, nomen.

Lemna Willd. Schleid., Linnaea in sub Lemna minor L. conjugata ex 13 (1839) 391, nomen synon. Linnaea in Lemna minor Incorrect citation Lemna cyclostasa Elliott ex Schleid., 13 (1839) 391, nomen synon. sub L. of Lemna minor var. cyclostasa Elliott,Bot. S. Carol. & Georgia2 (1824) 518. In literature this combination

has been ascribed Chevallier Par. but this is incorrect. repeatedly to ('Fl. 2, 1827, p. 256') Lemna Bauer in sub javanica ex Hegelm., Lemnac. (1868) 150, nomen synon. Spirodela oligorrhiza e javanica

Hegelm. = Spirodela punctata (G. F. W. Meyer) Thompson. BLUMEA VOL. No. 368 XVIII, 2, 1970

Lemna Enum. PL in microscopica Schur, Transs. (1866) 635, nomen synon. sub Telmatophace arrhiza Schur =

Wolffia arrhiza (L). Horkel ex Wimmer.

Lemna minima Chev. Linnaea in sub Lemna minor L. Incorrect citation ex. Schleid., 13 (1839) 391, nomen synon. Fl. of L. minor var. minima Chev., Par. 2 (1827) 256. We have not found any indication that Chevallier

minima Lemna minima Hist. Nat. 82 based his var. on Thuiller ex Beauvois, J. Phys. Chim. (1816) 113.

The diagnoses are very different.

Lemna minima H.B.K. Enum. PI. in Lemna minor L. Incorrect citation ex Kunth, 3 (1841) 5, nomen synon. sub L. H.B.K. Lemna minuscula Herter. of minuta (1815) =

Lemna minor Bot. Tasmania. var. gunnii Hegelm., Jahrb. 21 (1895) 292, nomen.

Lemna minuta Rafin., Med. Repos. N. York 5 (1808) 353, nomen.

Lemna monorhiza Montand. Lemnac. in sub Lemna minor L. ex Daubs, Monogr. (1965) 22, nomen synon. Incorrect reference to Lenticularia monorhiza Montand., Guide Bot. (1868) 308.

Lemna in obcordata Wallich, Cat. (1828) 181, no. 5201, cited Index Kewensis, not seen by us.

Lemna obcordata Hort. in the of Lemna minor but Bojer, Maurit. (1837) 358. Usually placed synonymy L., in need of reinvestigation.

A. Br. in L. Lemna ovata ex Krauss, Flora 28 (1845) 344, nomen,placed the synonymy of.Lemna minor on the

authority of Hegelmaier.

Lemna palustris Haenke ex Mert. & Koch, Roehlings Deutsch. Fl. ed 3, 1 (1823) 295, nomen in synon. sub

Lemna minor L.

Lemna Lemna platyclados Hegelm. ex Thompson, Rep. Mo. Bot. Gard. 9 (1897) 36. Incorrect citation of

valdiviana var. platyclados Hegelm.

Lemnac. sub Lemna pusilla Hegelm. ex Daubs, Monogr. (1865) 14, nomen in synon. Spirodela oligorrhiza

(Kurz) Hegelm. = Spirodela punctata (G. F. W. Meyer) Thompson. Incorrect citation of Spirodela oligor- rhiza y pusilla Hegelm. Lemna Enum. in transsilvanica Schur, PI. Transs. (1866) 635, nomen synon. sub Telmatophace orbicularis Schur Spirodela polyrhiza (L.) Schleid.

Lemna tricorrhiza Thuiller Schleid., Linnaea in sub Schleid. ex 13 (1839) 391, nomen synon. Telmatophacegibba

= Lemna gibba L.

Lemna Br. umbonata A. ex Hegelm., Lemnac. (1868) 156, manuscript name, referred toby Hegelmaier as Spirodela polyrhiza (L.) Schleid.

Lenticula cruciata Roxb. Fl. Ned. Ind. in sub Lemna trisulca L. Incorrect ex Miq., 3 (1855) 222. nomen synon. citation of Lemna cruciata Roxb.

Lenticula Elliott Kurz, Linn. Soc. Lond. 266, in sub Lemna minor L. cyclostasa ex J. 9 (1866) nomen synon.

Incorrect citation of Lemna minor var. cyclostasa Elliott.

Lenticula Fl. Fr. 189, in sub Lenticula = Lemna L. gibba Lamk, 2 (1778) nomen synon. vulgaris var. ß gibba

This combination was validly published by Moench, Meth. (1794) 319.

minima in minor L. Lenticula Humb. & Kunth ex Miq., Fl. Ned. Ind. 3 (1855) 222, nomen synon. sub

Incorrect citation of Lemna minuta H.B.K. (1815).

Lemnac. in Telmatophace cylindracea Welw. ex Hegelm., (1868) 123, nomen synon. sub Wolffia cylindracea den der Hegelm. = Wolffia globosa (Roxb.) Hartog & van Plas.

L. in Lemna Telmatophace generalis E. H. Krause in Sturm, Fl. Deutschl. ed 2,1 (1906) 184, nomen synon. sub gibba L.

EXCLUDED NAMES

Lemna Amer. = dimidiata Rafin., Monthly Mag. 2 (1817) 43 Ricciocarpus natans (L.) Corda, a liverwort. in Lemna minuta Steudel, Nom. ed 1, 2 (1823) 469. Incorrect citation of Lemma minuta Desrous. Lamk,

= Marsilea minuta L. Encycl. 3 (1792) 721. obcordata Lemna Vahl, Symb. Bot. 2 (1791) 95; Persoon, Syn. Pi. 2 (1807) 532; Beauvois, J. Phys. Chim.

82 = Hist. Nat. (1816) 113 Ricciocarpus natans (L.) Corda, a liverwort. in Lemna quadrifolia Steudel, Nom. ed. 1, 2 (1823) 469. Incorrect citation of Lemma quadrifolia Desrous.

Lamk, Encycl. 3 (1792) 720 = Marsilea quadrifolia L.