The genus Nymphoides Séguier (Menyanthaceae) in India

The genus Nymphoides Séguier (Menyanthaceae) in India

Aquatic Botany, 45 ( 1993 ) 145-170 145 Elsevier Science Publishers B.V., Amsterdam The genus Nymphoides S6guier (Menyanthaceae) in India V.V. Siva...

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Aquatic Botany, 45 ( 1993 ) 145-170


Elsevier Science Publishers B.V., Amsterdam

The genus Nymphoides S6guier (Menyanthaceae) in India V.V. Sivarajan and K.T. Joseph Department of Botany, University of Calicut, Calicut 673 635, Kerala, India (Accepted 24 November 1992 )

ABSTRACT Sivarajan, V.V. and Joseph, K.T., 1993. The genus Nymphoides S6guier (Menyanthaceae) in India. Aquat. Bot., 45: 145-170. The genus Nymphoides S6guier is represented by eight species in India. Of these, Nymphoides pelrata (Gmel.) O. Kuntze is restricted to temperate Himalaya and Kashmir while all others are tropical in distribution. The species are mainly distinguished by their floral morphology. Nymphoides aurantiacum (Dalz. ) O. Kuntze, Nymphoides parvifolium (Griseb.) O. Kuntze and Nymphoides sivarajanii Joseph have bisexual, homostylous flowers, while Nymphoides indica (L.) 0. Kuntze and N. peltata (Gmel.) O. Kuntze have bisexual, distylous ones. Nymphoides macrospermum Vasud. and Nymphoides krishnakesara Sivar. & Joseph are dioecious and Nymphoides hydrophylla (Lour.) O. Kuntze is monoecious or gynodioecious. A key for identification of the species, their nomenclature and complete descriptions are provided along with notes on habitat and other items.


Nymphoides S6guier (syn. Limnanthemum Gmelin) is a floating-leaved aquatic genus of 30-35 species (Cook et al., 1974) best represented in the Old World tropics (Wood, 1983 ). This genus can easily be distinguished by its petiole-like uniphyllous or many-leaved sympodial branches, rounded or cordate, floating leaves which resemble miniature leaves of Nymphaea, and umbellate clusters of sympetalous flowers. The earliest extensive work on this genus was done by Grisebach (1838, 1845 ), who treated it under the name Limnanthemum and included it under the tribe Menyanthideae of Gentianaceae (see also Gilg, 1895 ). This tribal position of the genus was agreed upon by subsequent workers until Stolt ( 1921 ) recognized Menyanthaceae as a distinct family, mainly based on morCorrespondence to: V.V. Sivarajan, Department of Botany, University of Calicut, Calicut 673 635, Kerala, India.

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phological and embryological grounds and was soon corroborated by Lindsey ( 1938 ) for anatomical reasons. This view has since been widely accepted by taxonomists. But the interrelationships and consequently the higher level classification of the family continues to be a matter of dispute, various authors assigning it to different orders such as Gentianales (Dahlgren, 1980; Morley and Toelken, 1983; Takhtajan, 1987 ), Polemoniales (Stebbins, 1974 ), Ligustrales (Tournay and Lawalr6e, 1952) and Solanales (Cronquist, 1981 ). Despite this, the generic limits within the family have remained almost unchanged from those established by Grisebach (1838, 1845), until recently, when problems cropped up in the delimitation and circumscription of Nymphoides and its closest ally, Villarsia. Aston ( 1969, 1973 ) has now redefined these two genera as follows: True aquatics; flowers in non-paniculate inflorescences; pedicels bent downwards after flowering; fruits ripen under water, indehiscent or breaking up irregularly ............................................................................... Nymphoides Mostly wetland herbs; inforescences erect, paniculate or at times condensed and capitate; pedicels not bent downwards after flowering; fruits valvate capsules, ripening above water .................................................. Villarsia INFRAGENERIC CLASSIFICATION

Grisebach ( 1838, 1845 ) is probably the only author who has attempted an infrageneric classification of the genus. He recognized two sections under Limnanthemum, mainly based on inforescence and seed characters, as follows: Sect. Waldschmidtia ("Semina pauca complanata, alata, ciliolata. Inflorescentia axinaris" ). Sect. Nymphaeanthe ("Semina subglobosa, exalata, laevia 1. muricata. Inflorescentia petiolaris" ). The sect. Waldschmidtia contained only one species, Nymphoides peltata, while the sect. Nymphaeanthe included all other species. Since then studies on various aspects, such as geographical distribution (Stuckey, 1974; Van der Velde et al., 1979 ), morphology and growth pattern (Goebel, 1891; Wagner, 1895; Van der Velde et al., 1979), seed surface patterns (Sivarajan et al., 1989 ), cytology (Ornduff, 1970a), palynology (Nilsson and Ornduff, 1973 ) and flavonoid data (Bohm et al., 1986 ), have largely supported the idea that N. peltata is distinct from other species of Nymphoides and that it deserves infrageneric status. After careful studies of the Indian species of the genus, the present authors



are also inclined to accept this view, but Grisebach's sectional nomenclature needs some revision in the light of the relevant rules in the Code. His sect. Waldschmidtia, which includes the type species of the genus, N. peltata, is, therefore, renamed as sect. Nymphoides (Art. 22. 1 ) while the name Nymphaeanthe is retained for the other section. PRESENT STUDY

It is well known that the genus Nymphoides is an unsatisfactory group to study with herbarium specimens alone "since most tropical species are indistinguishable vegetatively, and the flowers dry so poorly that they are usually useless for identification purposes" (Ornduff, 1970b). Since the genus displays a wide variety of floral mechanisms and biology--monoecism, homostyly, distyly, gynodioecism and dioecism--adequate studies are possible only with the aid of living plants and herbarium specimens with carefully prepared descriptive notes made on living plants in the field (Ornduff, 1970b). Except for some scattered work on aspects such as shoot morphology (D'Almeida, 1928 ), anatomy (Majumdar, 1938; Mehta, 1964; Kaul, 1976 ), embryology (Maheswari Devi, 1962 ), cytology (Srinivasan, 1941; Mukherjee, 1951; Srivastava, 1955) and heterostyly (Vasudevan Nair, 1975; Reddy and Bahadur, 1976 ) on certain isolated Indian species of the genus, there has not been any serious effort for an exhaustive, taxonomic study of the Indian taxa since Clarke (1883) and Subramanyam (1962). The taxonomic information on this genus provided in the Floras is based mostly on dried herbarium specimens and consequently collections are often confused and misidentiffed in most of the Indian herbaria. With this backdrop, it was felt that a revision of the Indian species of the genus based primarily on living plants would be a rewarding endeavour. MATERIALS AND METHODS

Extensive field studies were carried out in southern peninsular India, where all species except N. peltata grow in the wild. N. peltata was, however, studied from plants cultivated in the Botanic Garden, University of Calicut. In total, there are eight species in India of which N. peltata belongs to the section Nymphoides while the others, namely Nymphoides aurantiacum (Dalz.) O. Kuntze, Nymphoides hydrophylla (Lour.) O. Kuntze. Nymphoides indica (L.) O. Kuntze, Nymphoides krishnakesara Joseph & Sivar., Nymphoides macrospermum Vasud., Nymphoides parvifolium ( Griseb. ) O. Kuntze and Nymphoides sivarajanii Joseph, belong to the sect. Nymphaeanthe Griseb. Extensive notes on ecology, associated species and phenological characteristics were made in the field. Live plants were brought to the laboratory, critically studied using a



stereomicroscope and were illustrated. Studies on the flowers from herbarium specimens, although difficult, were carried out after soaking them in warm water for 30-60 min. Mature buds, in such cases, gave better results than open flowers. SYSTEMATIC TREATMENT OF NYMPHOIDES SI~GUIER

Nymphoides Srguier, FI. Veron. 3:121.1754.

Limnanthemum Gmelin, Nov. Comment. Acad. Sci. Imp. Petrop. 14 ( 1 ): 527.1770. Type species: Nymphoides aquis innatans Tournefort = Nymphoides peltata (Gmelin) O. Kuntze. Aquatic, monoecious, gynomonoecious, or dioecious, rhizomatous or stoloniferous perennials or rarely annuals with monomorphic or dimorphic shoots and leaves. In taxa with dimorphic leaves, the basal, vegetative leaves are rosulate and submerged and fertile leaves are floating and solitary at the apex of each petiole-like fertile branch which in some taxa produces secondary, sympodial, many-leaved fertile shoots with alternate or subopposite leaves. Flowers in most species in umbellate clusters of 2-many, arising most commonly from the junction of the petiole-like branch and the petiole of the fertile leaf, but sometimes axillary or lateral, tetra- or pentamerous, bisexual or unisexual, homostylous or heterostylous. Calyx deeply 5 (4-8) partite. Corolla, white or yellow, rotate, 5 (4-8) lobed, lobes often ornamented with fringes or crests. Stamens as many as corolla lobes, monomorphic in homostylous and dimorphic in heterostylous flowers, reduced to staminodes or absent in the female flowers of dioecious taxa. Pistil in male flowers reduced to pistillode, in bisexual and female flowers bottle-shaped with or without hypogynous disc glands, unilocular with few to many ovules. Style short, stout, rarely absent. Stigma variously lobed or lacerate. Capsules submerged, rupturing irregularly, few-many seeded. Seeds variable in number, size, shape and ornamentation. A genus of 30-35 species, most of them occurring in the tropical parts of the world, but best represented in the Old World (Wood, 1983 ); only a single species (N. peltata) restricted to temperate parts of Europe, Asia and America. In India, N. hydrophylla and N. indica are distributed almost throughout. N. peltata is known only from Western Himalaya and Kashmir while the other species are confined to the peninsular part.

Reproduction Most species of the genus are fairly good colonizers, inhabiting temporary ponds, pools, and flooded lowlands. Even though propagation by seed is an important way of multiplication, they display interesting supplementary, mostly vegetative, methods by which the populations can expand rapidly.



Most species of the genus are rhizomatous. During the onset of summer when the water-table starts falling, the aerial shoots die off. The bud-bearing rhizomes lie dormant for some time and germinate as soon as the next growing season starts. Some species also produce long stolons which give rise to new plants. New plants are also formed when detached branches become rooted and anchored to the substrate (e.g.N. hydrophylla, N. sivarajanii). The other common method of vegetative propagation that we have observed here is by bulbils (e.g.N. aurantiacum, N. hydrophylla). Leaves, when injured, produce leafy buds (bulbils) which develop into uniphyllous branches. Later they develop adventitious roots and, on detachment from the mother plants, float for some time and become anchored to a suitable substrate, finally developing into new plants. It has also been observed that, at times, the flower buds are transformed into vegetative buds which might develop into a new branch system of the mother plant itself or become detached from it and grow into new plants (e.g.N. sivarajanii). Pseudoviviparous germination has rarely been met within N. indica. Sect. Nymphoides Sect. Waldschmidtia Grisebach, Gen. Sp. Gent. 341. 1838. Inflorescence axillary. Seeds compressed, fiat, densely ciliate on margins.

Nymphoidespeltata (Gmelin) O. Kuntze, Rev. Gen. P1.2: 429. 1891; Makino, Ill. F1. Japan, 248. 1924; Hegi, Ill. F1. Mittel-Europa V. 3" 1961. t. 214.2. 1927; Tutin in Tutin et al., F1. Europ. 3: 68. 1972. (see Fig. 6G-I) Limnanthemum peltatum Gmelin, Nov. Comm. Acad. Petrop. XIV: 527. 1769. Menyanthes nymphaeoides L., Sp. PI. 145. 1753. Limnanthemum nymphaeoides (L.) Link, FI. Portug. 1: 344. 1809; Griseb., Gen. Sp. Gent. 341.1838; Clarke in Hook. f., F1. Brit. India 4:131.1885. Perennial herbs. Vegetative shoots dimorphic. Long shoots leafless, stolonlike, branched, creeping at the bottom layer. Short shoots from the nodes of long shoots, leafy. Fertile shoots from the axils of vegetative leaves. Leaves dimorphic. Vegetative leaves clustered, floating, ovate or orbicular, rounded at apex, deeply cordate at base; entire or subentire, green, to about 10 cm across; petiole 30-300 cm long. Fertile leaves similar but apparently alternate or subopposite and smaller; petiole 5-10 cm, base sheathing. Flowers bisexual, distylous, in apparently axillary, umbellate clusters of 2-5. Pedicels 4-10 cm long. Calyx deeply 5 partite, gland-dotted; lobes oblong-acute with hyaline margins, to 15 m m × 5 mm. Corolla yellow, tube to 7 m m long; lobes 5, ovateacute with often fimbriately toothed marginal wings. Stamens as many as petals, dimorphic, shorter than pistil in long-styled flowers and longer in shortstyled ones, inserted at the throat of the corolla, alternating with minute tufts



of yellow, glandular hairs. Pistil bottle-shaped; stigma bifid with irregularly toothed and folded lobes. Capsules large, ovoid or obovoid, with a persistent stylar beak, to 2 cm long and 1 cm in diameter, much exceeding the fruiting calyx. Seeds 20-25 in each capsule, brown, compressed, fiat, to 5 m m × 3.5 mm, densely long ciliate on the margins; testa cells with strongly sinuate depressed junctures. Ecology: In ponds, pools and lakes where it forms dense stands. Distribution: Most widely distributed species of the genus, and the only one which thrives in moderately cold climates. It extends from temperate Europe and West Asia, India to Japan and has now become naturalized in North America (Stuckey, 1974). In India, it is restricted to Western Himalaya and Kashmir. Notes: Of all the species o f N y m p h o i d e s , this is the best studied one (Wood, 1983). It has a distinctive form and growth pattern (Van der Velde et al., 1979 ). The morphology has been extensively studied by Goebel ( 1891 ) and Wagner ( 1895 ). Cytologically it is a hexaploid (2n = 54) while most tropical species are diploids or tetraploids (Ornduff, 1970a). The pollen grains differ from those of other taxa in their larger size and distinctly rugulose exine pattern (Nilsson and Ornduff, 1973 ) and the seeds in being flat, compressed and densely ciliate on margins (Sivarajan et al., 1989 ). Specimens examined; Kashmir: Rao 828, Wadhwa & Vohra 132 (CAL). Sect. Nymphaeanthe Sect. N y m p h a e n t h e Grisebach, Gen. Sp. Gent. 342. 1838 Inflorescence at the junction of branch and petiole, or lateral. Seeds turgid, not ciliate. Key to the species 1

Corolla yellow; flowers in 1-few flowered lateral clusters .........................


Corolla white; flowers in many-flowered clusters arising from the junction of petiole-like branches and actual petiole .............................................. 2 Leaves monomorphic, all floating and fertile ......................................... 3 Leaves dimorphic, basal leaves submerged, rosulate and sterile, fertile leaves floating ......................................................................................... 5 Corolla lobes not winged, but covered with long dense hairs within; floweres bisexual, distylous ................................................................ N. indica


2 2 3

N. a u r a n t i a c u m


3 4


Corolla lobes winged, not hairy within; flowers unisexual or bisexual and homostylous ............................................................................................4 Plants dioecious; corolla lobes with fimbriate wings; stigma bilobed with a whorl of radiating glandular hairs; seeds 3-6 mm across ....................... ..................................................................................... N. m a c r o s p e r m u m


5 5 6 6

Plants monoecious or gynodioecious; corolla lobes with flexuous (not fimbriate) wings and crests; stigma bilobed, not hairy; seeds to 2 mm across .................................................................................. N. hydrophylla Flowers unisexual; anthers blue; stigma with two whorls of long, radiating, glandular hairs ......................................................... N. k r i s h n a k e s a r a Flowers bisexual, homostylous, anthers not blue; stigma not hairy ....... 6 Wings on corolla lobes shortly, fimbriately toothed; stamens exserted from the corolla tube .................................................................. N. p a r v i f o l i u m Wings of the corolla lobes fimbriate with long hairs; stamens included in the corolla tube .................................................................... N. sivarajanii

N y m p h o i d e s a u r a n t i a c u m (Dalz.) O. Kuntze, Rev. Gen. PI. 1: 429. 1891; Subram., Aquat. Ang. 24. 1962; Cramer in Dassan. & Fosb., Rev. Handb. F1. Ceylon 3: 207. 1981. (See Fig. 1.) L i m n a n t h e m u m a u r a n t i a c u m Dalz. in Hooker's J. Bot. Kew Gard. Misc. 2: 136. 1850; Clarke in Hook. f., F1. Brit. India 4: 132. 1883; Trimen, Handb. FI. Ceylon 3: 190. 1895; Gamble, F1. Madras 2: 883. 1923. Type: Dalzell s.n., India, Bombay (lectotype K). L. b i f l o r u m Thw., Enum. P1. Zeyl. 205. 1860. Type: C.P. Moon 1869. Ceylon. Kalutara (lectotype PDA). L. f o r b e s i a n u r n sensu Griseb., Gen. Sp. Gent. 345. 1839 & in DC., Prodr. 9: 139. 1845, in part; Clarke, J. Linn. Soc. Bot. 14: 450. 1875 & Hook. f., F1. Brit. India 4:132. 1883, quoad specimen Macrae. Annual or perennial. Rhizome short, developing a cluster of uniphyllous, petiole-like, primary fertile shoots the length of which vary according to water depth. Secondary fertile branches from the node of the primary shoot, sympodial, trailing on the water surface with many floating, alternate, opposite or occasionally clustered leaves similar to primary leaves, but gradually getting smaller towards the tip of the branch; internodes 5-30 cm long; nodes occasionally rooting; roots fibrous, simple or branched, long. Leaves all fertile, floating, orbicular-rounded, deeply cordate at base with narrow sinuses, entire or subentire, green above, purplish and gland-dotted below, to about 8 cm across. Inflorescence 1-3 flowered arising from the junction of the branch and the petiole on the primary shoot and lateral on secondary shoots, subtended by a bract. Bract ovate or oblong, to 6 mm X 2 mm. Pedicel to 5 cm in fruits. Flowers bisexual, homostylous. Calyx deeply (4-) 5 lobed; lobes oblong-spathulate, glandular outside; apex purplish; margin membranous. Corolla orange-yellow; tube 7 mm long; lobes ( 4 - ) 5, to 7 mm × 4 mm, obovate-oblong;




Fig. 1. Nymphoides aurantiacurn: A, habit; B, single flower; C and D longitudinal section of flower; E, part of corolla opened showing the hairy flap and a stamen alternating with tufts of glandular hairs; F, pistil; G, fruit. (From Joseph 30265, CAL.)

apex distinctly 2 lobed; margin with fimbriately toothed wings. Stamens as many as petals, inserted at the sinuses of the corolla, alternating with tufts of yellow, glandular hairs; filaments short. Pistil bottle-shaped, yellow; disc glands not seen; style short, stout; stigma faintly (4-) 5 lobed. Capsule ovoid or obovoid, apiculate, as long as or slightly longer than the fruiting calyx. Seeds 1215 in each capsule, light brown, discoid, c. 2 mm across; surface densely aculeate; testa cells faintly fovulariate with obscure junctures. Ecology: It inhabits shallow ponds, pools, flooded lowlands and canals, often associated with species of Eleocharis, Eriocaulon and Najas. Not common. Flowers and fruits: August-November.


15 3

Distribution: South India and Sri Lanka. Notes: Contrary to Clarke's (1883) observation that the nodes are not rooting, we have found several specimens where the secondary fertile shoots are rooting at nodes. Grisebach ( 1838 ) has described L. forbesianum as having "corollae albae lobis intuse pilosis margine fimbriatis ..." based on two collections: "Mozambique (Forbes), Ins. Zeylon (Macrae)". Raynal (1974) has subsequently discovered that the description fits well with the African specimens, but was doubtful about the Ceylonese specimens. So he excluded Macrae's specimen from his description ofN. forbesianum. Cramer ( 1981 ), after examining both the syntypes of L. forbesianum Griseb., has now concluded that the Ceylonese material belongs to N. aurantiacum. Specimens examined: Kerala: K.T. Joseph 302658, Rugmini 1039, Sumathykutty 5861, Neena 8912, Jaisonlal 4367, Karthiayani 6557, Baby Jayalekha 7812, Pradeep 6176, Breezy George 7608, Jessy 2267 (CAL), Wight s.n. 33669. Karnataka: Meebold 9600. Concan: Hooker & Thomson s.n. (MH).

Nymphoides hydrophylla (Lour.) O. Kuntze, Rev. Gen. P1. 2: 429. 1891; Cramer in Dassan., & Fosb., Rev. Handb. F1. Ceylon 3: 208. 1981; Matthew, F1. Tam. Carnatic 1: 979. 1983; Nicols. et al., Interpret. Hort. Malab. 181. 1988. (See Fig. 2.) Menyanthes hydrophylla Lour., F1. Cochinch. 105. 1790. Type: Cochin China. Villarsia hydrophyllum (Lour.) Roem. & Schult., Syst. 4: 181. 1819. Limnanthemum hydrophyllum (Lour.) Griseb., Gen. Sp. Gent. 348. 1838. Menyanthes cristata Roxb., P1. Corom. 2: 3, t. 105. 1798. Type: Roxburgh P1. Cor. t. 105. Limnanthemum cristatum (Roxb.) Griseb., Gen. Sp. Gent. 342. 1838; Clarke in Hook. f., F1. Brit. India 4: 131. 1883; Gamble, Fl. Madras 2: 883. 1923. Nymphoides cristatum (Roxb.) Kuntze, Rev. Gen. P1. 2: 429. 1891. Tsjeroea-citambel Rheede, Hort. Malab. 11: 57, t. 29.1692. Rhizomatous, monoecious or gynodioecious, annual or perennial. Rhizome 1-2 cm thick, sending out long stolons producing new plants at their tips. Primary fertile shoots many, arising from the axils of scales on the rhizome, length highly variable depending on water depth, uniphyllous, often producing secondary, zig-zag, sympodial, many-jointed shoots, each joint bearing a single floating leaf. Leaves all fertile, floating, ovate to orbicular, rounded, deeply cordate at base with narrow sinuses, entire, green, sometimes with purplish blotches above, gland-dotted and prominently nerved below, membranous, 6-12 cm across. Petiole to 2.5 cm long. Flowers bisexual and





Fig. 2. Nymphoideshydrophylla:A, habit; B, female flower; C, bisexual flower; D, longitudinal section of bisexual flower; E, longitudinal section of female flower; F, pistil showing hypogynous disc glands; G, fruit. (From Joseph 17787, CALl.)

female, in umbellate clusters of 10-20 at the junction of the branch and petiole, subtended by a small, ovate bract. Pedicels 3-5 cm long. Calyx deeply 5 partite; lobes narrowly lanceolate, acute, persistent, 3-5 m m long. Corolla white with or without a yellow throat; tube 2 m m long with a ring of glandular hairs at the throat; lobes 5, oblong, obtuse or retuse at apex, 8-9 m m X 3-4.5 mm, with flexuous, membranous wings on the margins and a similar median longitudinal crest within. Stamens 5, inserted about half-way up the corolla tube, highly reduced and staminodal in female flowers. Pistil bottle-shaped with 5, minute, orbicular, disc glands at the base; style indistinct; stigma 2


15 5

lobed. Capsule oblong, torulose when ripe, to 16 mm long. Seeds 4-6 in each capsule, brown, discoid, to 2 mm in diameter; surface aculeate; aculea in bundles of 3-7, with gemmate protuberances towards distal ends; testa cells convex and rugose; junctures depressed and irregular. Ecology: A common species in temporary ponds, pools and in flooded lowlands. Flowers and fruits: September-March. Distribution: India, Sri Lanka, Malaysia and Southern China. Notes: Adventitious roots produced from the nodes sometimes aid the plant in vegetative propagation. Bisexual and female flowers are alike, except that the stamens are highly reduced to staminodes in the latter. N. hydrophylla is a diploid species having monoecious and female plants and is distributed throughout India. Vasudevan Nair (1975) has discussed the breeding behaviour of this species in detail. Flowers in both morphs are superficially similar, but the females have reduced, sterile stamens. The affinities of this species are not yet clear, but in any case it is not closely related to N. indica (Ornduff, 1970a). N. macrosperrnum, and N. krishnakesara, are also closely related, but are dioecious. The latter also differs in its dimorphic leaves, distinctly blue anthers in the male flowers, two whorls of radiating stigmatic hairs in the females and in several other respects. Both are known only from flooded paddy fields and shallow ponds in Malabar, northern Kerala. Specimens examined: Andhra Pradesh: Raju 211, Bourne 3202, Gamble 15797, Subba Rao 45924, Narayana 16831, Ellis 16848, Sebastine 11705 (MH). Andaman and Nicobar Islands: s.n. 842 (CAL). Assam: Aburer 58, Panigrahi 12138, Hooker & Thomson s.n. (CAL), Wood 168 (MH). Delhi: Rodiw 8037 (CAL). Himachal Pradesh: Duthie s.n. (CAL). Karnataka: Raghavan 97481, Fischer 4538, Talbot 868, Ramesh 673 (MH). Kerala: Ramachandran 54093, 59081 & 65266, Nair 59662, Ansari 70966, Nair 19096, Joseph 17787, Vajravelu 48836 & 44563, Vasudevan Nair 4, Ramamurthy 48535 & 56588, Fischer 3828 & 1708, Lawson 303 (MH), K.T. Joseph 30277, 38631, 38544, 38566, 38637, 19795 & 38597, Sumathykutty 8914, Sivarajan 1470 & 980, Indira 11648, Surendran 8656, Ayshabi 5703 (CALI). Maharashtra: Dalzell s.n., Gamble 15797, Bourne 3202, John Cherian 106185, Kamat 270130 (MH). Madhya Pradesh: Maheswari 4581, Sebastine 7641, Duthie 9573 (MH). Orissa: Mooney 2413, Sreemadhavan 1281, Subramnian 10518, Parmer 8706, Shetty 544, Verma 1715, Bikkim Tibu & Rhomoo 3685 & 3700 (CAL). Tamil Nadu: Perumal 181114, Ramamurthy 53612 & 60116, Venugopal 22668 & 21424 (MH), Wight 2577, Graham 69, Bourne 3202 (MH, CAL), Mathew & Paranaivaw 23707, Nair, 56588 (MH). Uttarpradesh: Bell 218, Inayat 22314, Panigrahi 2726, 16729 & 5864, Duthie 6665 (CAL). West Bengal: Mukerjee 8726, Verma 139, Kurz s.n., Dutta 168, Dutt



659, Thothathiri 9599, Harza 167, Ghosh 812 & 8337, Parry s.n., Hooker & Thomson s.n., Rich 766, Gamble 524 (CAL).

Nymphoides indica (L.) O. Kuntze, Rev. Gen. P1. 2: 429. 1891; Subram., Aquat. Ang. 24. 1962; Raynal, Adansonia Ser. 2: 14: 416. 1974; Cramer in Dassan. & Fosb., Rev. Handb. F1. Ceylon 3: 207. 1981; Nicols. et al., Interpret. Hort. Malab. 181. 1988. (See Fig. 3.) Menyanthes indica L., Sp. P1. 145. 1753; Roxb., FI. Ind. 2: 31. 1824. Type: Herman s.n. Ceylon (holotype, BM). Limnanthemum indicum (L.) Griseb., Gen. Sp. Gent. 343.1838 & in DC., Prodr. 9: 139. 1845; Clarke in Hook. f., F1. Brit. India 4: 131. 1883; Gamble, FI. Madras 2: 833. 1923. Limnanthemum wightianum Griseb., Gen. Sp. Gent. 344. 1838 & in DC., Prodr., 9.139. 1845. Syntype: Wight s.n. India Madras (lectotype, K). Limnanthemum humboldtianum (Kunth) Griseb., Gen. Sp. Gent. 347. 1839. Type: Humboldt, Venezuela (P). Limnanthemum kleinianum Griseb., Gen. Sp. Gent. 344. 1839. Type: Wallich s.n. India (K). Nedel-ambelRheede, Hort. Malab. 11:55-56 t. 28. 1692. Annual or perennial, rhizomatous herbs. Rhizome 1-5 cm thick with prominent branch scars all along its length, sending out long stolons which produce new plantlets. Primary fertile branches many, petiole-like, and uniphyllous, highly variable in length depending on the depth of water. Secondary branches sympodial, zig-zag, many-jointed, trailing on water surface; each joint uniphyllous; nodes often rooting. Leaves all cauline, fertile and floating, ovate-orbicular, rounded, deeply cordate at base with narrow sinuses, to about 30 cm across, glossy green above, pale and gland-dotted beneath, entire or subentire, thick, fleshy, brittle when dry. Petiole short, to 2 cm long. Flowers bisexual, distylous in umbellate clusters of 15-35, from the junction of the petiole and the branch, subtended by bract; bract ovate or oblong, to 8 mm X 5 ram. Pedicel 5-12 cm long. Calyx deeply 5 (4-8) partite; lobes oblong-acute, green with hyaline margins, to 7 mm X 2 mm. Corolla white with a yellow throat; tube 2.5 mm; lobes 5 (4-8), elliptic or oblong, acute, densely covered with long, white hairs within, to 15 mm X 5 mm. Stamens as many as corolla lobes, dimorphic, longer than the pistil in short-styled flowers and shorter than pistil in long-styled ones; filaments yellow. Pistil bottle-shaped; style stout, 1 mm in short-styled flowers, 3 mm in long-styled ones; stigma sinuately 4-8 lobed; hypogynous disc glands as many as stamens, orbicular. Capsules ellipsoid, torulose when ripe, as long as or shorter than the fruiting calyx. Seeds 1825 in each capsule, brownish, discoid, 1.5 mm across; surface with scattered clusters of tubercles; testa cells variously shaped, flat with thin, raised junctures.




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Fig. 3. Nymphoides indica: A, habit; B, rhizome showing branch scars and roots; C, secondary fertile branches; D, longitudinal section of short-styled flower; E, pistil of short-styled flower; F, longitudinal section of long-styled flower; G, pistil of long-styled flower; H, fruit. (From Joseph 43002, CAL. )



Ecology: Very common in shallow ponds, pools and flooded lowlands, during the monsoon. Flowers and fruits: September-March. Distribution: Pantropical. Notes: The distylous condition seems to be of great evolutionary significance in this genus as it forms an intermediate stage between the bisexual, homostylous, self-compatible taxa and the dioecious species through the gynodioecious condition met within N. hydrophylla (see also Ornduff, 1966 ). N. indica (sensu lato) is a complex group distributed throughout the Old World and New World tropics but which has been treated under different binomials on the basis of its flower colour. Grisebach ( 1838 ) has recognized several species such as L. kleinianum, L. wightianum, both from India, and L. humboldtianum from the New World. Clarke ( 1883 ) reduced the former two into the synonymy ofL. indicum. During a recent visit, one of us (VVS) was able to examine some Indian specimens ofL. kleinianum (Assam: Masters s.n. Peninsular India: Wight 1846. Tenasserim: Heifer 5842, LE) and L. wightianum (Kerala: Wight 2579) in the Leningrad Herbarium and was convinced that both are conspecific with N. indica. Seed coat micromorphology (Sivarajan et al., 1989 ) also corroborates this. Despite the fact that the neotropical N. humboldtianum is consistently tetraploid (2n = 36 ), while the Old World N. indica is diploid (2n= 18 ), there are no consistent morphological differences to separate them (Ornduff, 1970a,b) and this has now been supported by the flavonoid data as well (Bohm et al., 1986). Specimens examined: Andhra Pradesh: Chandrabose 45249, Sebastine 11613 (MH). Andaman and Nicobar Islands: Prain s.n. (CAL). Assam: Keeinira s.n. (CAL). Bihar: Hooker 414, Wood XCVII, Kerr 2076, Prain s.n. (CAL). Gujarat: Andrews A322 (CAL). Jammu and Kashmir: Vohra & Wadhwa 364 (CAL). Karnataka: Barber 8835, Austead 13306, Raghavan 9723, Ramesh & Prakash 6602, Saldana 12228 & 1523, Ramamoorthy 1926, Hohenacker 309, Falconer s.n. (CAL). Kerala: Wight 1845 (CAL, LE). Ramachandran 6037, Nair 59989, Ansari 70019, Rajasekhara Mudaliar s.n., R.V. Nair 1, Sebastine 26742, Mohanan 52675, Ramamurthy 74743 & 74863, Ramachandran 60037, Fischer 3827, Lawson 195 (MH), K.T. Joseph 43002, 41294, 3977, 395354, 38961, 38625 & 39434, Mary Cherian 12497, Agnes Richard 12042, Karthiayani 6493, Sivarajan 866, Ajitha 13586, Letha 10718, Sujaya 11020 (CAL), Dalzell s.n. (MH), Santapau 3027, Sedgewick & Bell 7681, Andress A322, Billore 116652 (CAL). Madhya Pradesh: Subramanian 7144 & 10855, Panigrahi 21971, Dutta 396, Rich 986, Sebastine 7646, Chowdri Ram s.n. (CAL). Orissa: Rao 30270, Atkumar 217626, Panigrahi 23975, 8349 & 8264, Mooney 2412, Fischer 303235 (CAL). Punjab: Bell 303224 (CAL). Rajastan: Verma 1714, Wadhwa 9482, Shetty 209 (CAL). Tamil Nadu: Wight 2579 (CAL, LE), Henry 49457 & 49526, Nair 5688, Raju & Naganathan 17525, Ramamoorthy 60116 & 53612, Sebastine 13737, Joseph



Iil,, ~go/I 4ram

Fig. 4. Nymphoides krishnakesara: A, habit (female plant); B, rhizome; C, basal leaves; D, a female branch with leaf and flowers; E, male flowers: F, male corolla opened showing stamens and pistillode; G, female flower; H, corolla of female flower opened to show staminodes and pistil; l, pistil; J, fruit. (From Joseph 43001, CAL )



158131, Daniel Sunderaj & Rao 93890, Mathew & Venugopal 17283 & 23240, Thomson s.n. (MH). Uttarpradesh: Sunderan Maji 7532, Arora 6080 & 5963, King s.n., Allen s.n., Uotila 17660, Ritchie s.n. (CAL). West Bengal: Utpal Chatterjee 116, Durra 91 & 395, Kurz s.n., Banerjee 152955, Sinclair 2839A & 327 (CAL).

Nymphoides krishnakesara Joseph & Sivar., Nord. J. Bot. 10:281-284. 1990. Type: Joseph 43001. Kerala, India (MH, Z, CAL). (See Fig. 4.) Annual or perennial, dioecious, rhizomatous herbs. Rhizome to about 5 cm long, non-stoloniferous. Branches monomorphic, all fertile, arising from the rhizome, petiole-like, uniphyllous. Leaves dimorphic; the basal ones sterile, many, rosulate, submerged, spathulate with a winged, spongy petiolar part and an expanded ovate or oblong lamina, to 4 cm long; fertile leaves floating, very shortly petioled, ovate to orbicular, rounded at apex, deeply cordate below, entire, glabrous, glossy green above, to 9 cm × 6 cm. Flowers in umbellate clusters of 40 or more, arising from the junction of petiole and the branch, unisexual, 1-1.5 cm across, subtended by ovate-acute, translucent bracts. Pedicels 2-5 cm. Male flowers: calyx 5 partite; lobes oblong, obtuse or subacute, green, glabrous, to 6 m m × 1.5 mm, persistent. Corolla white, rotate, deeply 5 lobed; tube short with 5 flap-like, minute scales below the throat; lobes to 10 m m X 2 mm, obtuse with narrow, shallowly fimbriate marginal and median wings, the median wing extending only from the apex to the middle of the lobe. Stamens 5, inserted at the throat of the corolla and alternating with the petals; filaments 2 mm long; anthers blue, oblong, as long as or longer than filaments; pollen yellow. Pistillode 3 mm long, prominent, oblong, obtuse and slightly emarginate at apex without stigmatic hairs, occasionally with an abortive ovule on each placenta; hypogynous disc glands 5, fleshy, entire. Female flower: calyx and corolla as in male. Staminodes similar to fertile stamens in male flowers in their number and insertion, but much smaller, white. Pistil bottle-shaped, 3 mm long; stigma apparently sessile, green, of 2 seriate, radiating, minutely papillate hairs, the outer ones deflexed, the inner ones erect, almost half as long as the ovary; hypogynous glands as in male. Capsules about 1 cm long, beaked, exceeding the persistent calyx. Seeds 5-10 in each capsule, cream or brown-yellow, obovoid, compressed, to 4 mm long and 2.5 mm wide, surface aculeate; aculea bulbous at base, sharply pointed at apex. Ecology: Found growing in shallow, temporary ponds on rocky hillocks in north Kerala during the rainy season. It usually grows in association with Blyxa octandra (Roxb.) Thw., Wiesneria triandra Mich., Eriocaulon truncatum Mart. and Rotala malampuzhensis Vasudevan Nair ex Cook. Blue anthers, unique growth pattern of fertile branches and winged-petiole of basal, sterile




.i ~ .







Fig. 5. Nymphoides macrospermum: A, habit (male plant); B, habit (female plant); C, male flower; D, pistillode with hypogynous disc glands; E, female flower; F, pistil; G, longitudinal section of female flower; H, fruits. (From Joseph 38636.)

leaves are distinctive. The male and female plants grow together and their ratio is almost 1 : 1 (Joseph and Sivarajan, 1990). Flowers and fruits: August-November. Distribution: Known only from Kerala.



Specimens examined: Kerala: Joseph 43001 (MH, Z, CAL), Premalatha 3050, Kadeejakutty 258, Sudhirkumar 2617, Shreedevi 1033, Santha 3456, Jayakumar 2211 (CAL).

Nymphoides macrospermum Vasudevan, Kew Bull. 22:101-106. 1968. Type: Vasudevan s.n. Kerala, India (K, MH). (See Fig. 5. ) Annual or perennial, dioecious, rhizomatous herbs. Rhizome 1-2 cm thick, stoloniferous. Branches dimorphic, all fertile; primary branches petiole-like, 1-1.5 m long depending on the depth of water, uniphyllous; secondary branches arising from the nodes of primary branches, sympodial, manyjointed, each with a single, floating leaf at the apex, producing clusters of flowers and fleshy, tuberous roots at the nodes. Leaves ovate-orbicular, rounded at apex, deeply cordate at base, to about 16 cm across, entire, green, gland-dotted below, membranous; leaves on secondary branches smaller. Petiole to 2.5 cm long. Flowers unisexual, in umbellate clusters of 25-50 at the nodes, subtended by an auriculate, ovate-obtuse bract. Pedicels 2-6 cm long, pinkish. Male flowers: calyx deeply 5 partite; lobes oblong-obtuse, pinkish, to 2.5 m m × 1 mm. Corolla white, 1-1.5 cm across; tube very short; limb 5 lobed; lobes oblong or elliptic, acute, to 6 mm X 2 mm, hairy at base and with fimbriately toothed wings on the margins and with a similar median longitudinal crest within. Stamens 5, inserted at the throat of corolla; filaments 2 mm long, white; anthers pale purple or yellow. Pistillode bottle-shaped with a faintly lobed apex. Female flowers: calyx and corolla as in male. Staminodes similar to fertile stamens, but highly reduced and non-polleniferous. Pistil bottleshaped without a distinct style; stigma yellowish, bifid, each lobe fimbriate with a marginal row of long, radiating hairs. Capsules ovoid, torulose when ripe, much longer than the fruiting calyx, to 8 mm long. Seeds 2-6 in each capsule, ovoid or ellipsoid, to 4.5 m m X 3.5 mm; surface with clustered aculea; testa cells convex, polygonal and foveolate with straight depressed junctures. Ecology: A comparatively rare species found in the flooded paddy fields, ponds and slow-running streams along the coastal areas of Kerala, associated with Nymphoides indica and Nymphaea spp. Flowers and fruits: September-December. Distribution: Coastal regions of Kerala. Endemic. Notes: Unisexual flowers and large seeds are very distinctive characters of this species. In vegetative characters it closely resembles N. indica. It also resembles N. krishnakesara in its dioecious nature, but the latter differs in its dimorphic leaves and female flowers with two whorls of radiating stigmatic hairs. Vasudevan (1968) and Ornduff (1970a) are of the opinion that N. macrospermum originated from N. indica. Male and female plants grow together, but the male plants are in an overwhelming majority. The ratio is 30:1 or sometimes more in extensive popu-




ii E V"

t/ I]

Fig. 6. A-F. N. parvifolium: A, habit; B, rhizome; C, flower;D, corolla opened to show stamens and pistil; E, pistil; F, fruit. (From Sivarajan 431, CAL.) G-I. N. peltata." G. habit; H, flower;I, corolla opened showingstamens and pistil. lations. There is no difference between male and female plants in their vegetative state. Specimens examined: Kerala: Vasudevan s.n. (K, M H ), K.T. Joseph 38636, 41296, 4800, 39636, Susheela s.n. ( C A L ) , R a m a m u r t h y 80429, Cook, Rix & Schneller 281 ( M H ) .



Nymphoidesparvifolium (Griseb.) O. Kuntze, Rev. Gen. P1.2: 429. 1891, Subram., Aquat. Ang. 24. 1962; Cramer in Dassan. & Fosb., Rev. Handb. FI. Ceylon 3: 210. 1981 'Parviflora', Mani. & Sivar., F1. Calicut 175. 1982 (See Fig. 6. ) Limnanthemum parvifolium Griseb. in DC., Prod. 9:141.1845; Clarke, J. Linn. Soc. Bot. 14: 450. 1875 & in Hook. f., F1. Brit. India 4: 132. 1883; Trimen, Handb. F1. Ceylon 8: 189. 1895; Gamble, F1. Madras 2: 883. 1923. Type: Wallich Num. List. 4351. Burma, Tavoy (holotype, K-Wall. ) Limnanthemum moonii Thw., Enum. PI. Zeyl. 205.1860. Type: Moon, C.P. 2842. Ceylon, Kalutara (lectotype PDA). Limnanthemum parvifolium var. moonii (Thw.) Clarke in Hook. f., F1. Brit. India 4:132. 1883. Annual or perennial, rhizomatous herbs. Rhizome short, obconical. Branches all fertile, very slender, petiole-like, uniphyllous, 8-20 cm long. Leaves dimorphic; sterile leaves many, in a basal rosette, submerged; petiole 2-4 cm long, often winged; lamina spathulate, to 3 cmX 1.5 cm; fertile leaves solitary at the apices of capilliform branches, floating, ovate-orbicular, rounded or obtuse at apex, deeply cordate at base with narrow sinuses, to 4 cm X 3 cm, membranous, entire, green. Petiole short, 2-5 mm. Flowers bisexual, homostylous in umbellate clusters of 4-8 at the junction of the petiole and the branches. Calyx deeply 4 (-5) lobed; lobes oblong-acute, to 2 mm × 1 mm, pinkish at apex, hyaline at margin. Corolla white with a yellow throat; tube 2-3 mm, with a ring of hyaline hairs at the throat; lobes 4 (-5), oblong or elliptic, 3-5 mm long, margins fimbriately toothed towards the apex. Stamens as many as corolla lobes, inserted below the throat; filaments 1-1.5 mm long, alternating with minute, stalked tufts of white, glandular hairs. Pistil bottle-shaped with 4-5 disc glands below; style short, but distinct; stigma bilobed. Capsules ellipsoid, apiculate, torulose when ripe, longer than the fruiting calyx. Seeds 8-15 in each capsule, light brown, discoid, to 1 mm across; surface tuberculate; testa cells foveolate with sinuate and faintly raised junctures. Ecology: Occasionally seen in shallow ponds and in flooded paddy fields, associated with Dopatrium junceum ( Roxb. ) Benth., Rotala malampuzhensis and Nymphoides indica. Flowers and fruits: September-December. Distribution: Southern India, Sri Lanka, Malaysia and tropical Australia. Notes: It is poorly represented in herbaria, probably because it is a rather rare species. The most delicate of all Indian species of the genus, it can easily be characterized and identified by its dimorphic leaves, capilliform branches, white spongy roots and rhizome and the nature of its corolla lobes. N. parvifolium with its dimorphic leaves and homostylous flowers is morphologically quite distinct from N. indica, but the seed surface patterns in the two species











Fig. 7. Nymphoides sivarajanii: A, habit; B, rhizome with stolons; C, flower; D, corolla opened; E, pistil; F-I, different stages of establishment of a new plant either from a detached flowering branch or bulbil; J-M, stages in the formation of roots and leaves in daughter plants; N, fruit. (From Joseph 39070, CAL.)

point to a close affinity (Sivarajan et al., 1989). N. sivarajanii, discovered and described recently (Joseph, 1991 ) from the flooded paddy fields of Malappuram Distrct, Kerala, is also closely allied to N. parvifolium but the for-



Fig. 8. Scanningelectronmicrographsof seeds; A, N. aurantiacum ( X40); B, N. hydrophylla ( X40); C, N. indica ( X40); D, N. krishnakesara ( x 20 ); E, N. macrospermum ( X20); F, N. parr~folium ( X 80 ); G, N. peltata ( X 20); H, N. sivarajanii ( X 20). mer can readily be recognized by its large and profusely branching habit, large number of flowers in each cluster, profusely fimbriated corolla lobes and anthers borne on level with the sinus of the corolla. Specimens examined: Karnataka: Saldanha, Ramesh & Sreenath 8862, Talbot 1577, Sedgewick & Bell 6666 (MH). Kerala: Wight 4351, Rangachari s.n., Cook, Rix & Schneller 297, Ramamurthy 48562 (MH), K.T. Joseph 38536, 38433, 38459, 38433, 39072, 39068 & 38459, Sreedevi I 114, Mohanan 10016, Beena 3735, Letha 10546, Kadeejakutty 135, Indiradevi 9022,

16 7



N y m p h o i d e s hydrophylla


~, k r i s h n a k e s a r a

N. a u r a n t i a e u m

N. p e l t a t a

Fig. 9. Map showing distribution of N. hydrophylla, N. aurantiacum, N. krishnakesara and N. peltata in India.

Sivarajan 431 (CAL), Ansari 74328, Stocks s.n., Wight 1848 (MH). Maharashtra: Ritchie et Dalzell s.n. (MH).

Nymphoides sivarajanii Joseph, Willdenowia 20:135-138. 1991. Type: Joseph 30243, Kerala, India (MH, B, CAL). (See Fig. 7.) Annual or perennial, rhizomatous herb. Rhizome robust, to about 6 cm long, sending out long stolons. Branches all fertile, monomorphic, many from the axils of basal leaves, uniphyllous, petiole-like. Leaves dimorphic; vegetative leaves basal, submerged, rosulate; petiole 8-15 mm long; lamina ovate, obovate or rhomboid, obtuse at apex, sometimes very small and indistin-




~*'* •


* Nymphoides indiea •



o N. parvifolium •

N. sivarajanii

Fig. 10. Map showing distribution ofN. indica, N. macrospermum, N. parvifolium and N. sivarajanii in India.

guishable from the petiole; fertile leaves floating, ovate to orbicular, rounded at apex, deeply cordate at base, with a broad, triangular sinus, 2-4.5 cm × 1.54 cm, entire, often pinkish. Petiole 2-5 m m long. Flowers bisexual, homostylous, in umbellate clusters of 5-15 at the junction of the petiole and branch. Pedicels 2-4 cm long. Calyx deeply (4-) 5 partite; lobes linear or oblong, subacute, to 4 m m X 1 mm, often pink with hyaline margins. Corolla white with a yellow throat; tube short with a ring of long, white hairs at the throat; lobes (4-) 5, oblong, to 8 m m long with densely fimbriate marginal wings. Stamens as many as corolla lobes, inserted in the corolla tube, alternating with minute, stalked tufts of glandular hairs. Pistil bottle-shaped; style short, stout; stigma resembling a bottle-mouth; hypogynous disc of 4-5 minute glands. Capsules oblong or obovoid, slightly longer than the fruiting calyx, beaked at apex with the persistent stylar base. Seeds 15-20 in each fruit,



brownish, discoid, to 1 m m across; surface tuberculate; testa cells foveolate, fiat with raised, sinuate junctures. Ecology: This species is fairly common in the flooded lowlands in certain areas of Malappuram District in Kerala during the rainy season and grows in association with Limnophila aquatica (Roxb.) Alston, Sacciolepis indica (L.) Chase, Blyxa aubertii Rich. and Monochoria vaginalis (Burm. f. ) C. Presl. Flowers and fruits: August-October. Distribution: Coastal lowlands in Kerala. We have not been able to collect it from anywhere else than the type locality. One specimen at MH (Mohan 58393) from Ochira in Quilon district in Kerala, identified as N. indica, looks like N. sivarajanii, but has no flowers to confirm it. Specimens examined: Kerala: Joseph 30243 (MH, B, CAL), Joseph 39070 (CAL). ACKNOWLEDGEMENTS

We are grateful to the Directors of K, LE, PARIS, CAL and MH for facilities and other assistance. We also thank Dr J. Bogner, Munich, for literature and Dr C.D.K. Cook, Ziirich, for encouragement. Prof. R. Vasudevan Nair, Palghat, Kerala, kindly made the drawings. REFERENCES Aston, H.I., 1969. The genus Villarsia (Menyanthaceae) in Australia. Muelleria, 2: 3-6. Aston, H.I., 1973. Aquatic Plants of Australia. Melbourne University Press, Melbourne. Bohm, B.A., Nicholls, K.W. and Ornduff, R., 1986. Flavanoids of the Menyanthaceae: intra and interfamilial relationship. Am. J. Bot., 73:204-213. Clarke, C.B., 1883. Gentianaceae. In: J.D. Hooker (Editor), Flora of British India, Vol. IV. Reeve, London, pp. 93-132. Cook, C.D.K., Gut, B.J., Rix, E.M., Schneller, J. and Seitz, M., 1974. Water Plants of the World. Junk, The Hague. Cramer, L.H., 1981. Menyanthaceae. In: M.D. Dassanayake and F.R. Fosberg (Editors), A Revised Handbook to the Flora of Ceylon, Vol. 3. Oxford and IBH, New Delhi, pp. 206212. Cronquist, A., 1981. An Integrated System of Classification of Flowering Plants. Columbia University Press, New York. Dahlgren, R., 1980. A revised system of classification of the Angiosperms. J. Linn. Soc. Bot., 80: 91-124. D'Almedia, J.F.R., 1928. On the shoot morphology ofLimnanthemum. J. Indian Bot. Soc., 7: 1-11. Gilg, E., 1895. Gentianaceae. In: A. Engler and K. Prantl (Editors), Die Natiirlichen Pflanzenfamilien, Vol. 4. Engelmann, Leipzig, pp. 50-108. Goebel, K., 1891. Morphologische and biologische Studien. VI. Limnanthemum. Ann. Jard. Bot. Buitenzorg, 9: 120-126. Grisebach, A., 1838. Genera et Species Gentianearum. Cotta, Stuttgart. Grisebach, A., 1845. Gentianaceae. In: A. De Candolle (Editor), Prodromus Systematis Naturalis, Vol. 9, Fortin, Masson, Paris, pp. 38-141. Joseph, K.T., 1991. Nymphoides sivarajanii (Menyanthaceae), a new species from India. Willdenowia, 20: 135-138.



Joseph, K.T. and Sivarajan, V.V., 1990. A new species ofNymphoides (Menyanthaceae) from India. Nord. J. Bot., 10: 281-284. Kaul, R.B., 1976. Anatomical observations on floating leaves. Aquat. Bot., 2:215-234. Lindsey, A.A., 1938. Anatomical evidence for the Menyanthaceae. Am. J. Bot., 25: 480-485. Maheswari Devi, H., 1962. Embryological studies in the Gentianaceae: Gentianoideae and Menyanthoideae. Proc. Indian Acad. Sci. B., 56:195-216. Majumdar, G.P., 1938. A preliminary note on polystely in Limnanthemum cristatum and Ottelia alismoides. Curr. Sci., 6: 383-385. Mehta, A.S., 1964. A study of the primary phloem of the petiole of Nymphoidespeltatum (Gruel.) O. Kuntze. J. Indian Bot. Soc., 43: 257-261. Morley, B.D. and Toelken, H.R., 1983. Flowering plants in Australia. Regby, Adelaide, pp. 247258. Mukherjee, A., 1951. Cytology ofLimnanthernum cristatum Griseb. Curt. Sci., 20: 328-329. Nilsson, S. and Ornduff, R., 1973. Menyanthaceae Dum. World Pollen and Spore Flora, 2: 120. Ornduff, R., 1966. The origin of dioecism from heterostyly in Nymphoides (Menyanthaceae). Evolution, 20:309-314. Ornduff, R., 1970a. Cytogeography of Nymphoides (Menyanthaceae). Taxon, 19:715-719. Ornduff, R., 1970b. Neotropical Nymphoides (Menyanthaceae): Meso-American and West Indian species. Brittonia, 21: 346-352. Raynal, A., 1974a. Le genre Nymphoides (Menyanthaceae) en Afrique et h Madagascar. 1: Morphologie. Adansonia, 2 (14): 227-270, 405-408. Reddy, N.P. and Bahadur, B., 1976. Heterostyly in Nymphoides indica. J. Indian Bot. Soc., 55: 133-140. Sivarajan, V.V., Chaw, Shu-Miaw and Joseph, K.T., 1989. Seed coat micromorphology of Indian species ofNymphoides (Menyanthaceae). Bot. Bull. Acad. Sinica, 30: 275-283. Srinivasan, A., 1941. Cytomorphological features ofLimnanthemum cristatum Griseb. and Enicostemma littoraleBlume. Proc. Indian Acad. Sci. B, 14: 529-542. Srivastava, M.G., 1955. Chromosome number in genus Limnanthemum. Sci. Cult., 21:215. Stebbins, G.L., 1974. Flowering Plants: Evolution Above the Species Level. Belknap-Harvard, Cambridge. Stolt, K.A.H., 1921. Zur Embryologie der Gentianaceen and Menyanthaceen. Sv. Vet. Acad. Handi. II, 61 ( 14): 1-56. Stuckey, R.L., 1974. The introduction and distribution of Nymphoides peltaturn (Menyanthaceae) in North America. Bartonia, 42: 14-23. Subramanyam, K., 1962. Aquatic Angiosperms. CSIR, New Delhi. Takhtajan, A., 1987. Systema Magnoliophytorum. Nauka, Leninopli. Tournay, R. and Lawalrre, A., 1952. Une classification nouvelle de families appartenant aux orders des Ligustrales et des Contortres. Bull. Bot. Soc. Fr., 99: 262-263. Vasudevan, R., 1968. A new species of Nymphoides (Menyanthaceae) from India. Kew Bull., 22: 101-106. Vasudevan Nair, R., 1975. Heterostyly and breeding system of Nymphoides cristatum (Roxb.) O. Kuntze. J. Bombay Nat. Hist. Soc., 72: 677-682. Van der Velde, G., Giesen, Th. G. and van der Heijden, L., 1979. Structure, biomass and seasonal changes in biomass of Nymphoides peltata (Gmelin) O. Kuntze (Menyanthaceae). A preliminary study. Aquat. Bot., 7: 276-300. Wagner, R., 1895. Die Morphologie des Limnanthemurn nymphaeoides (L.) LK. Bot. Zt., 53: 189-205. Wood, Jr., C.E., 1983. The genera of Menyanthaceae in the South-eastern United States. J. Arn. Arb., 64:431-445.