The Morphology and Embryology of prosepinacoides~Willd. with a Discussion on the Systematic Position of the Family

by P. MAHESHWARIand B. M. JoHRI* ReceivedJune 30, 1956

The family Limnanthaceae comprises two genera, Floerkea and . The embryology of has been studied by Stenar (1925), Eysel (1937), Fagerlind (1939) and Mason (1951) but without any agreement on several critical points. More recently Mathur (1956) has investigated L. douglasii and L. striata and concluded that the embryo sac is tetrasporic corresponding to the pseudomono- sporic, biphasic type' of Harling (1950). The earlier interpretation of Stenar and Eysel of an Adoxa type of development is not confirmed (see also Fagerlind, 1939). Mason (1952) has recently conducted a systematic study of the genus Limnanthes and "utilized the traditional morphological approach, as well as chromosome studies of hybridization as embodied in more recent taxonomic techniques." On Floerkea, a monotypic genus of North America, there is a general article by Russell (1919) and a short note by Johni & Maheshwari (1951) on its embryo sac and endosperm. The systematic position of the family Limnanthaceae has been a debated ques- tion. Brown (1933) recognized some common features with the hypogynous families but did not assign a definite place to it. Engler & Prantl (1897) placed it in the order Sapindales and Hutchinson (1926) in the . As will be shown here, none of these assignments is satisfactory and porbably the family needs to be raised to an ordinal rank. Materials and methods While on tour in the U.S.A..in 1946, one of us (P.M.) fixed some material of the from Madison, Wisconsin. Additional material was obtained in 1952 from Dr. L. Farquharson (Bloomington, Indiana) and Dr. L. A. Kenoyer (West Michigan College), and in 1952 from Dr. M. Fulford (Cincinnati, Ohio) and Dr. C. T. Mason Jr. (Stanley, Wisconsin). To all these persons we offer our most grateful thanks. Buds flowers and fruits were prepared and imbedded in the usual way. Sections were cut at 6-15 microns and stained in iron-haematoxylin as well as safranin and * Departmentof Botany, Universityof Delhi,Delhi 8, India. 1) When only one of the four megasporenuclei contributesto the formationof the embryo sac, the developmentis pseudomonosporic.The term biphasicmeans that twopost-meiotic divisions occur beforethe organizationof the embryosac. Oct.-Nov. 1956 Bot. Mag. Tokyo, Vol. 69, Nos. 820-821 411

fast green. Both combinations gave good results. Dissections were also made of the endosperm at the globular stage of proembryo and stained with cotton blue in lactophenol.

Morphology Floerkea proserpinacoides, popularly known as the `false mermaid weed', is a short-sized (about 10 cm. high) annual, marshy herb with pinnately dissected, simple, alternate leaves.

Figs. 1-11. Floral morphology and anatomy. (a, androecium ; c, corolla ; d, stylar bund- les ; k, calyx ; o, ovary wall; ov, ovule; st, style ; v, ovular bundles). Fig. 1. L.s. flower at mature embryo sac stage ; the swollen portion of the filament on the right represents the basal gland. x 25. Figs. 2-8. Transection of a flower with tricarpellary gynoecium showing origin of vascular traces to various organs ; approximately at level marked in Fig. 1, but of a younger flower. x 39. Figs. 9-11. T. s. older flower (bicarpellary gynoecium), more or less at levels, 7, 8 and 11 indicated in Fig. 1. x 39. 412 植 物 学 雑 誌 第69巻 第820-821号 昭 和31年10-11月

The solitary axillary flowers possess three large, imbricate and three contorted petals (Figs. 1, 8, 10, 11) ; rarely there may be four sepals. The sip are arranged in two whorls, the outer alternating with the petals (Figs 7-10) and having conspicuous basal glands. The gynoecium is usually tricarpellars but sometimes bicarpellary, with a gynobasic style (Figs. 1, 8, 10). The ovaries alternate with the petals, and each has a single basal-parietal ovule (Figs. 1, 8, 10) The vascular supply of the flower is shown in Figs. 1-11. There are three bundles at the upper end of the pedicel (Fig. 2), alternating with which arise the three traces (k1, k2, k3) to the sepals (Fig. 3). The traces to the petals (c1, c2 c3) alternate with those of the sepals (Fig. 4). Further up each shows one median and two lateral bundles, while the petal traces proceed undivided (Fig. 11) Next are the six staminal traces (al-a6) which arise at about the same level (Fig. 5) The remaining bundles of the central ring supply the gynoecium. One bundle enters each ovule, curves round and branches, the ramifications continuing up tc the integument (Figs. 1, 7-10). Bundles alternating with the ovular supply enter the style (Figs. 6-8, 9, 10) and bifurcate in the region of the stigma (Fig. 11). A* in LininnnT e s (5aimders_ 192R~ _ the ov a rv wall i s devoid of any vascular sunnly.

Figs. 12-25. Microsporogeneis and male gametophyte. Figs. 12, 13. Portions of anther lobes at tetrad and uninucleate pollen grain stage respectively. x 434. Figs. 14, 15. Micro- spore mother cells, Meiosis I and II. x 1585. Fig. 16. Cytokinesis by furrowing. x 1585. Fig. 17. Decussate tetrad. x 1585. Fig. 18. Uninucleate pollen grain. x 1585. Fig. 19. Division of microspore nucleus, x 1585. Figs. 20--23. Two-celled pollen grains. x 1585. Fig. 24. Outline diagram for Fig. 25. x 50. Fig. 25. Portion of anther lobe marked in Fig. 24, to show region of dehiscence. x 434. Oct.-Nov. 1956 Bot. Mag. Tokyo, Vol. 69, Nos. 82O821 413

Microsporogenesis and male gametophyte

Each microsporangium of the dithecous anther shows a group of hypodermal archesporial cells. An endothecium, two persistent middle layers and the glandular tapetum are derived from the primary parietal layer (Figs. 12, 13, 25). During reduction divisions the tapetal cells enlarge and become binucleate, but later the nuclei fuse (Figs. 12, 13). The inner tangential walls of the tapetal cells break down at the microspore stage (Fig. 13), and as the pollen grains mature the tapetum disorganizes. The reduction divisions are simultaneous, secondary spindles are laid down during Meiosis II, and cy tok inesis occurs by furrowing. Centripetal wedges formed by the special mucilaginous wall bring about quadripartition (Figs. 12, 14-16). The microspores are usually arranged tetrahedrally or in a decussate fashion (Figs. 16, 17) ; isobila teral tetrads also occur sometimes. The microspores enlarge and the wall differentiates into an exine and an intine (Fig. 18). In some of the microsporangia there is widespread degeneration of the microspores (Fig. 13). On division the nucleus gives rise to a small generative and a large vegetative nucleus separated by a membrane (Figs. 19, 20). As the latter soon dissolves, the generative cell moves into the cytoplasm of the vegetative cell where it acquires a lenticular shape (Figs. 21, 22). In some pollen grains the vegeta- tive nucleus had flattened and came to lie adjacent to the generative cell (Fig. 23). The mature pollen grains are rounded and 4-colporate, and the exine has warty projections (Figs. 20-23). During maturation of the anther, the partition walls between the adjacent micro- sporangia break down (Fig. 24), and dehiscence occurs by longitudinal slits along the junction of the pollen sacs. In this region the epidermal and endothecial cells are smaller and thin-walled. Further, the former lack tannin and the latter are devoid of fibrous thickenings (Fig. 25). The stamens of the outer whorl dehisce earlier than those of the inner.

Ovule

The ovule is un itegmic and tenuinucellate, and the integument makes its appea- rance almost simultaneously with the differentiation of the archesporium. The curvature of the ovule is very rapid so that by the time the first meiotic division is over, it becomes anatropous (Figs. 26, 27). Besides the epidermis, the nucellus comprises only one more layer of cells on the sides (Fig. 30). This layer is crushed during megasporogenesis and the epidermis meets the same fate soon after. The integument is massive and shows a conspicuous vascular supply (Figs. 1, 8, 10, 28). During its expansion the embryo sac consumes the adjacent cells of the integument (Figs. 42, 43). Mathur (1956) reports that in Limnanthes douglasii a few cells of the integu- 414 植 物 学 雑 誌 第69巻 第820-821号 昭 和31年10-11月

Figs. 26-43. Megasporogenesis and female gametophyte. Figs. 26-28. L , s. ovule3 at arche- sporial, 2-nucleate and mature embryo sac stage; Figs. 27 and 28 are outline diagrams for Figs. 31 and 42 respectively. x49. Fig. 29. Multicel led archesporium. x 801. Fig. 30. Megaspore mother cell, x 801. Figs. 31--37. Stages in developmet of embryo sac; explana- tion in text. x 801. Figs. 38-39. Abnormal gametophytes ; Fig. 38. x 801; Fig.39. x 528. Figs. 40, 41. Mature embryo sacs. x 528. Figs. 42, 43. Same, 1. s. portions of ovules; note the thickened integumentary cells at the micropylar end. x 316. Oct.-Nov. 1956 Bot. Mag. Tokyo, vol. 69, Nos. 820-821 415 ment at either end of the embryo sac become thick-welled. They have dense cytoplasm and appear to have a nutritive function. In F'loerkea proserpinacoides such thick-walled cells are distinguishable only at the micropylar end (Figs. 42, 43).

Megasporogenesis and female gametophyte

There is a group of hypodermal archesporial cells (Fig. 29) but only one of them functions. As it differentiates into the megaspore mother cell, prominent vacuoles appear at either pole (Fig. 30). The first meiotic division results in a markedly smaller nucleus which migrates to the chalazal end, and a larger one which stays on in the centre o f the cell (Fig. 31). The smaller chalazal nucleus usually degenerates soon after formation (Figs. 32, 33). The upper nucleus undergoes the second reduction division and again pro- duces one small nucleus which migrates to the chalazal end, and a larger nucleus occupying a central position (Fig. 32). The second nucleus at the chalazal end often divides to form two daughter nuclei (Fig. 33). Sometimes it is the first-formed chalazal nucleus which divides (Fig. 34) but such a behaviour is rare. The upper larger nucleus has divided in Figs. 35-37. The two lower nuclei in Figs. 36 and 37 may have been formed as a result of division of the first-formed chalazal nucleus. It is also possible that they correspond to the two chalazal nuclei in Fig. 32; or, perhaps the first chalazal nucleus had already degenerated and dis- appeared and they are products of division of the second chalazal nucleus. In Fig. 35 these two nuclei seem to have fused. Unfortunately our preparations did not show any mitoses and therefore no definite conclusions can be made about the origin of the chalazal nuclei in Figs. 32-34, 36, 37 and 39. The abnormal gametophyte represented in Fig. 38 is even more difficult to interpret. Since the nuclei vary considerably in size, it is probable that in this case there were irregularities in the meiotic divisions. The two nuclei at the micropylar end undergo one more division and the daugh- ter nuclei organize into the egg apparatus and the upper polar nucleus (Figs. 40- 42). A lower polar nucleus is always present (Figs. 40-42) ; in origin it may either be the second chalazal nucleus (formed after Meiosis II of the upper larger nucleus) or its daughter nucleus. In Fig. 39 the large nucleus below the egg apparatus is probably the fusion nucleus and the two nuclei at the base may represent the two lower nuclei shown in Fig. 34 which have persisted for quite a long time. In Fig. 42 the nucleolus of the upper polar nucleus appears to be in a process of budding. The mature embryo sac is conspicuously broad in the middle and narrow at the poles (Figs. 28, 40-43). The synergids are beaked and hooked and lack a basal vacuole (Fig. 41) ; the nucleus usually lies in the centre of the cell although some- times it may be basally situated (see left synergid in Fig. 40). Since walls are not laid down after the first or the second meiotic division, the development of the embryo sac is tetrasporic as also in the allied genus Limnanthes 416 植 物 学 雑 誌 第69巻 第:820-821号 昭 和31年10刷11月

Ψ 「ou＼ ミ膨 〆o層 一 〇乙 轡 ノ631 5Z し;{1・∵・.●.;、∵1 ＼

Figs.44-63.Endospermandembryo.(ρ,endospermpouch;μ,pollentube;s,persistent

synergid).Fig.44.Doublefertilization.×259.Fig.45.Embryosacwithproembryoand undividedprimaryendospermnucleus.x259.Fig.46.Same,showingzygoteandtwoen-

dospermnuclei.x259.Fig.47.Upperpartofembryosacwithpersistentsynergid,pro-

embryoandfreeendospermnuclei.×259.Figs.48,51,53.Ls.ovul6satearlyandlate

globular,aidheart-shapedstageofembryo;Figs.48and51areoutlinediagramsforFigs. 49and52respectively,x38.Figs.49,50,52.Upperportionsofembryosacs;notethe

gradualaggregationofendospermnucleiadjacenttothepersistentsynergidandformation of'thepouch,.x259.,Fig.54.Endospermand.globularproembryofromwholemount.x65.

digs.55-63.Stagesindevelopmentoftheglobularproembryo.x259. Oct.-Nov. 1956 Bot. Mag. Tokyo, Vol. 69, Nos. 820-821 417

(Mathur, 1956). The nearest approach is to the Drusa type except that the activity of the nuclei situated at the chalazal end is very much restricted. Neither in Mathur's material of Limnanthes nor in our preparations of Floerkea could there be seen any protrusion of the micropylar end of the 4-nucleate embryo sac as figured by Fagerlind (1939). In Fleerkea the daughter nucleus resulting from the second meiotic division of the upper nucleus invariably migrates to the chalazal end (see Figs. 32-34) while in Limnanthes it is situated at a somewhat higher level. Antipodal cells were not observed and only in a few embryo sacs one or two nuclei were present in the chalazal end of the organized gametophyte (e.g. Fig. 39).

Fertilization

Double fertilization occurs as usual (Fig. 44) and remnants of the pollen tube persist until a late stage (Figs. 46, 47, 49, 50, 52, 63). Normally one of the synergids is destroyed during fertilization but sometimes both may remain intact (Fig. 44). The surviving synergid enlarges, takes a dense stain, and persists until the forma- tion of the globular proembryo. Probably it has a haustorial function (Figs. 46, 47, 49, 50, 52). Fagerlind (1939) and Mathur (1956) also report a similar behaviour of one of the synergids in Limnanthes.

Endosperm

As a rule the primary endosperm nucleus divides earlier than the zygote. In Fig. 46 the first division has already taken place but the zygote is undivided. Fig. 45 shows the reverse condition where we have a well advanced proembryo but an undivided primary endosperm nucleus. Repeated nuclear divisions, which are not always synchronous, result in a large number of nuclei about 215 at early globular, 370 at late globular and 780 at the heart-shaped stage of the embryo. These nuclei take up a peripheral position (Figs. 48, 51, 53) although from the very beginning there is a tendency for an aggregation of the endosperm nuclei in the vicinity of the persistent synergid (Figs. 49, 50). The nuclei are imbedded in dense cytoplasm and the adjoining integumentary cells soon show signs of being corroded. Gradually a pouch is formed in this region containing 30-35 nuclei (Figs. 50-54). The pouch is always on the funicular side (Figs. 51, 53) and functions as an efficient absorbing organ. It has not been observed in Limnanthes by any of the investigators on this genus. The peripheral layer of cytoplasm containing the endosperm nuclei invades the integumentary tissue all around the embryo sac so that the pouch is no longer distinguishable in older stages (compare Figs. 53, 75, 76). The endosperm remains nuclear throughout and is consumed during the matura- tion of the embryo. No more than a darkly staining streak of its remnants persists between and around the cotyledons. 418 植 物 学 雑 誌 第69巻 第820-821号 昭 和31年10-11月

Embryo

ThedevelopmentoftheembryoisshowninFigs.55-63,afewstagesbein≦

show:nincidentallyillFigs.45,47,49,50and52.Thesuspensorusuallyconsistsoゴ

auniseriaterowof3-4cells,butsometimes6-9cellsmaybeformed.Theupper

mostcellelongatesconsiderably,becomesvacuolatedandmaysimulateasynergic

(Figs.52,62).Inonecaseithadundergonealo:ngitudinaldivisio:n(Fig.63).

Theprogressoftheembryofromthelateheart-shapedtothematurestagei∈

indicatedinFigs.75,76,77and64.

Figs.64-74.Fruit.(c,cotyledon;i,integument;1,leaf;pe,pericarp;y,radicle;st,stem

tip).Fig.64.L.s.fruit.x14.Figs.65一 一74.T.s.fruitapproximatelyatlevelsindicatedin

Fig.64.x14.

Seedandfruit

Thefruitisasingle-seeded,i:ndehisce:ntache:ne(nutlet).Theembryoocc・ul

theentireseedcavityandcomprisestwolargecotyledons,asmallradicle,and

stemtipwithtwopairsofleaves(FYgs.64,70).ThereservefoodmaterialappE

tobeproteinaceous.Afeatureofspecialirnterestconcerningthecotyledon

their'backwardextensionandbifurcationoneithersideoftlleradiclesothati Oct.-Nov. 1956 Bot. Mag. Tokyo, Vol. 69, No. 820-821 419 cross section at the upper end there appear to be four lobes (Figs. 65-67). The embryo has a well developed vascular supply which extends into the bifurcated portions of the cotyledons (Figs. 65--74). Neither Fagerlind (1939) nor Mathur (1956) examined the mature seeds of Limnanthes and it would be interesting to know if the cotyledons in this plant are like those of Floerkea.

Figs. 75-81. Fruit, seed coat and pericarp. (e, embryo ; en, endosperm ; i, integument ; pe, pericarp). Fig. 75. L.s. fruits, note the persistent gynobasic style. x 18. Fig. 76. Older fruit. x 18. Fig. 77. T.s. fruit. x 18. Fig. 78. Portion of ovary wall, integument and endo- sperm enlarged from seed approximately of the same age as represented in Fig. 76. x 308. Fig. 79. Same, enlarged from Fig. 77; peripheral cells of the embryo are also shown. x 308. Fig. 80. Pericarp, seed coat, degenerated remains of endosperm, and portion of a cotyledon ; enlarged from Fig. 66. x 308. Fig. 81. Thickenings on the outer tangential walls of epider- mal cells of pericarp. x515.

At the time of fertilization the integument consists of 14-16 layers of parenchy- matous cells. The inner_ 6-8 layers are absorbed by the endosperm (Fig. 78), but the rest of the cells enlarge except in the neighbourhood of the vascular bundles 420 植 物 学 雑 誌 第69巻 第820-821号 昭 和31年10-11月

(Figs.78,80).Inlaterstagesallthecellsshowdepositsofstarchexceptingthe

epidermisandhypodermiswhichbecomeslightlythick-walled(Figs.78,80).

TheovarywallYs5to6-layeredandlocalizedgrowthatseveralpointsgive; anu:nevenapPearancetotheoutersurface(Figs.75,76,78,79,64-74).1τ 】additio]

toageneralenlargementofthecells,theepidermisa血dhypodermisacquirethic]

walls(Fig.80).AsinLimnanthes(Mathur,1956)theoutertangentialwallofthe

epidermisdevelopsnumerouspyramidalthickenings(Fig.81)whichgivestheperi

carpaspecificpattexn.

Thepericarpandthetestaremainadherenttoeachother.Afewcellso

thepericarpandthehypodermisofthetestaarefilledwith`ta:nni:n'andimpartl

reddish-browstinttothefruit.

Discussion

Thefamily:Lim:na:nthaceaeisbasedoηthetypegenus五 魏 〃σ〃漉63describedb】

Brownire1833.ThematerialwastakentoBnglandfromCaliforniabyDougla

afterwhomthespeciesL,douglasiiisnamed.Browsalsoincludedthegenu

Floerkeczintheabovefamily,butadded:"Examinationprovedthesetwoplant

tobesonearlyakinthattheymightperhapsbeincludedinthesamegenus."

Baillon(1871,1878)observedtetramerousflowersinboth.FZo〃 ん6αwhichis:normalll

trimerousa:ndinL伽 御 鋭 乃6swhichispentamerousandonthisbasisunitedthen

underthecommonnameFloerked.SeveralworkersfollowedBaillon,whileother mai:ntai:nedthattheseplantsbelongtoseparatege:nera(5θ6Mason,1952).

Thea伍nitiesofthefamilyLimnanthaceaearealsou:nsettled.Brown(1833

wrote:"Theplaceofthisfamilyisnotabsolutelydetermi:ned,butitissuggestel thatintworemarkablepointsofitssむructure,namely,theprese:nceofgla:ndssub tendingthealternatefilaments,andtheexistenceofagynobase,itmorepearl; approachestoHypogynousfamilestha:nPerigynous,withwhichithashithertobeeI associated,"莞B瓠tham&Hooker(1862)recog:nizedtheindividualstatusofthetw(

generabutplacedtheminaseparatetribe,theLimnantheaeundertheGeraniaceaE Onthebasisofthepositio:noftheseed,Engler&Prant1(1897)retainedth twogenerainthefamily:Limna:nthaceaeandassignedittotheorderSapi:ndaleε OntheotherhandHutchinson(1926)transferredittotheGeranialeswhichinthei turnareregardedasderivedfromtheCaryophyllales.Whileadmittingconsider able9昂psbetwee:nthetwogroups,hedrawsattentiontosomeafHnitybetweeコ themthroughtheLimnanthaceae.

WhereasmostsystematistsaccepttheassignmentoftheLimnanthaceaetoth

Gera:niales,fromthemorphologicala:ndembryologicalstandpointt:herearemarke( dissimilaritieswiththemembersoftheSapindalesaswellastheGera狛ialesaswil beborneoutfromthefollowingtable(forliteraturereferencesseeAnantaswam】

Rau,1940;D'Amato,1939;Erdtma:n,1952∫Johri&Ahuja,1956;KUhn,1928;Law rence,1951;Mathur,1956;Schnarf,1931;andVenkateswarlu&Narayana,1955)

*QuotedfromMason(1952). Oct.-Nov. 1956 Bot. Mag. Tokyo, Vol. 69, Nos. 820-821 421

Thus, the Limnanthaceae differ from both the Sapindales and the Geraniales in having (1) only herbaceous members, (2) gynobasic style, (3) unitegmic, tenuinu- cellate, basal-parietal ovules, and (4) an unusual type of tetrasporic embryo sac. The Sapindales are mostly shrubs and trees, the leaves are usually compound, the flowers are often unisexual, the stamens are in a single whorl, and the embryo is 422 M 7 # ; 69 82O-8214te a 311O-41J

curved with crumpled cotyledons. The Sapindales as well as the Geraniales lack a gynobasic style, the ovules are penduluos on axile placentae, the pollen grains are 3-colporate, ovules are bitegmic and crassinucellate, the development of the embryo sac is predominantly monosporic, and nucellar embryony occurs in some of the families under both the orders. Concerning pollen morphology, Erdtman (1952) remarks : " The grains in Lim- nanthaceae are not similar to those in Balsaminaceae, Convolvulaceae, Coriariaceae, G eraniaceae, Hydrocaryaceae, Nymphaeaceae-Cabomboideae, Sapotaceae and Tro- paeolaceae." Judging from present evidence, then there are very few features common to the Limnanthaceae and members of the Sapindales and Geraniales. Since some of the families usually included in the above orders have already been given an ordinal rank (see Hutchinson, 1926; Lawrence, 1951; Core, 1955), we are of the opinion that the Limnanthaceae may also be given a similar status and placed in a new order Limnanthales.

Summary

,Floerkea proserpinacoides is a monotypic North American plant belonging to the family Limnanthaceae. It bears solitary trimerous flowers. The stamens are arranged in two whorls of which the outer alternates with the petals and has basal glands. The gynoecium is usually tricarpellary, the ovaries are separate from each other and the style is gynobasic. There is a single, basal-parietal, ascending ovule in each ovary. The anther wall comprises the epidermis, fibrous endothecium, two persistent middle layers and glandular tapetum. The reduction divisions are simultaneous, cytokinesis occurs by furrowing and the tetrads are decussate or tetrahedral. The pollen grains are tetracolporate and are shed at the 2-celled stage. The ovule is anatropous, unitegmic and tenuinucellate with an integumentary vascular supply. A group of archesporial cells differentiates in the young nucellus but only one of them functions as the megaspore mother cell. A parietal cell is not cut off and the development of the embryo sac is tetrasporic. The mature gametophyte shows the egg apparatus, and two polar nuclei ; rarely one or two antipodal nuclei are also seen. The endosperm is nuclear and walls are not laid down. The endosperm deve- lops a pouch-like haustorium at the micropylar end towards the funicular side. The zygote divides transversely. The mature embryo has a short radicle. The cotyledons have backward extensions which become forked. The testa consists of 8-10 and the pericarp of 3--4 layers. The pericarp has an uneven surface and the outer tangential wall of the epidermis develops pyramidal thickenings. The epidermis and hypodermis of testa and some cells of the pericarp contain 'tannin'. The fruit is an indehiscent achene (nutlet). Oct.-Nov. 1956 Bot. Mag. Tokyo, Vol. 69, Nos. 820-821 423

The morphological and embryological features of the Limnanthceae do not sup- port its inclusion either in the order Sapindales or the Geraniales. It is suggested that this family may be given an ordinal rank under the name Limnanthales.

We are indebted to Mr. S. N. Dixit who prepared most of the illustrations, and also to Mr. S. P. Bhatnagar and Mr. Hardev Singh for other assistance in the pre- paration of this paper.

Literature cited

1. Anantaswanzy Rau, 1\'I.,Proc. Indian Acad. Sci. B. 11: 100-106 (1940). 2. *Baillon, H., Ad. ansonia 10: 360-371 (1871). 3.* , Histoire des plantes. Paris (1878). 4. Bentham, G. & Hooker, J.D., Genera Plantarum. London (1862). 5. *Brown, R., London & Edinburgh Phil. Mag. 3: 70-71 (1833). 6. Core, E.L., Plant . New Jersey, U.S.A. (1955). 7. D'Amato, F., Nuovo Giorn. Bot. Ital. 46: 470-509 (1939). 8. Engler, A. & Prantl, K., Die natUrlichen Pflanzenfamilien. Leipzig (1897). 9. Erdtman, G., Pollen Morphology and Plant Taxonomy. Angiosperms. Waltham, Mass., U.S.A. (1952). 10. Eysel, G., Die Embryosack entwicklung von Limnanthes douglasii R.Br. Diss. Marburg (1937). 11. Fagerlind, F., Acta Hort. berg. 13 : 1-49 (1939). 12. Harling, G., Acta Hort. Berg. 15:136-168 (1950). 13. Hutchi nson, J., Families of Flowering . I. Dicotyledons. London (1926). 14. John, B.M. & Mahesh- wari, P., Curr. Sci. 20: 44-46 (1951). 15. John, B.M. & Ahuja, M.R., Curr. Sci. 25: 162-164 (1956). 16. Kuhn, G., Bot. Jb. 61: 325-379 (1928). 17. Lawrence, G.H.M., Taxonomy of Vascular Plants. New York (1951). 18. Mason, C.T., Jr., American J. Bot. 38: 17-22 (1951). 19. , Univ. Calif. Publ. Bot. 25: 455-512 (1952). 20. Mathur, Nirmala, Phytqmorphology 6: 41-51 (1956). 21. Rusell, A., Contr. Biol. Lab. Univ. Pennsylvania 4: 401-418 (1919). 22. Saunders, E.R., New Phytol. 27: 199-213 (1928). 23. Schnarf, K., Vergleichende Embryo- logie der Angiospermen. Berlin (1931). 24. Stenar, H., Svensk Bot. Tidskr. 19: 133-152 (19.25). 25. Venkateswarlu, J. & Narayana, L.L., Curr. Sci. 24: 52-F3 (1955).

* Originals not seen .