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(Last Modified On 2/7/2013)
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(Last Modified On 2/7/2013)
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Genus
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NYMPHAEA L.
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PlaceOfPublication
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Sp. PI. 510. 1753
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Reference
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J. E. Smith in Sibth. & Smith, Fl. Graec. Prodr. 1: 360. 1808-9. nom. conserv.
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Synonym
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Castalia Salisb. in Ann. Bot. 2: 71. 1805. nom. rejic.
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Description
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Rhizomatous, acaulescent, laticiferous, aquatic perennials. Leaves alternate, often polymorphic, long-petiolate; floating leaves ovate to orbicular with a basal sinus; submergent leaves infrequent and emergent leaves rare. Flowers perfect, usually tetramerous, cyclic to spiral, hypogynous to perigynous, often large and showy, white, cyanic or xanthic, floating or emergent on long peduncles arising from the more or less horizontal rhizome; sepals 4(-8), free or slightly connate basally; petals rather numerous, in several series, the inner grading into the sta- mens; stamens numerous, the outer with petaloid filaments and short broad anthers, the inner with narrower filaments and longer anthers, the anthers all introrse; car- pels 3-many, apocarpous to syncarpous, superior or inferior, the carpellary styles radiating from a more or less coalescent disk; ovules numerous, anatropous, pen- dulous from the inner angles of the carpels. Fruit baccate, mucilaginous, ripening under water, many-seeded, the seeds indurate, operculate, arillate; endosperm scanty, perisperm copious, the embryo minute.
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Distribution
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According to Wood (in Journ. Arn. Arb. 40: 98. 1959), the genus contains about 35 species of widespread occurrence (but lacking in New Zealand and the Pacific slope of North America) in quiet, fresh (rarely brackish) waters.
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Note
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After a detailed morphological study of 11 species and two hybrids of Nymphaea, Moseley (in Bot. Gaz. 122: 256. 1961) concludes that the arrangement of the floral organs is in transition from spiral to cyclic phyllotaxy, although superficially the carpels, and occasionally other floral parts, appear to be cyclic. For illustrations of some of the Mexican species, the reader is referred to the work of Blackaller (in An. Inst. Biol. Mex. 7: 415. 1937). The genus has not been monographed in entirety since the work of Conard (Carn. Inst. Wash. Publ. 4: 1. 1905). The reader should consult that monograph for some of the synonymic intricacies of the three species found in Panama.
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Key
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a. Flowers opening by day; carpels free at the sides, the wall between ovary cells being double, the styles short and stout; filaments prominently produced be- yond the anthers; leaves coarsely dentate, black-spotted beneath, at least when young ........................ 1. N. AMPLA aa. Flowers opening by night; carpels fused at their sides, the wall between ovary cells being single, the styles long and clavate; filaments scarcely produced be- yond the anthers; leaves entire to dentate, pallid or cyanic below. b. Leaves coarse, sinuate to dentate, usually cyanic below; petioles and pe- duncles not villose near their apex; sepals conspicuously lineolate ....... 2. N. RUDGEANA bb. Leaves thin, entire, pallid below; petioles and pedicels occasionally villose apically; sepals obscurely lineolate ................. 3. N. BLANDA
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