Page:The Journal of Indian Botany.djvu/634

192

Submerged plants. Stem slender elongate and often branched, bearing leaves for several inches. Leaves very slender, or capillary, 1-5 in. long. Head numerous, 1/10 to 1/16 in., on slender peduncles usually in a terminal umbel, but often also from more than one node. Receptacle glabrous or hairy and chaffy with adherent bracts. Sepals of the male more or less free. All parts of both sexes in threes; stamens 6; anthers black.

Though placed first for convenience because differing from the rest of the genus in their very pronounced aquatic habit and elongated stem, the species which comprise this group should almost certainly be regarded not as primitive, but as aquatic offshoots from the original stock, to which the next group, SIMPLICES, are nearest.

A difficult group to work out in old collections, the heads and the flowers being small, and some confusion has crept in with regard to the species. Linnaeus in Sp. PJ. Ed. 1. 1753 p. 87 founded E. setaceum on an Indian plant giving as synonym Randolia malabarica and quoting also Rheed. Mai. [Hortus Malabaricus] 63. He mentioned only the 6-angled stem and capillary leaves. In Fl. Zeylanica (1747) p. 50 he had mentioned in addition the membraneous sheath and submerged roots. Steudel in Syn. PI. Cyp. (1855) took this species to be the one with glabrous floral bracts, that being the common Malabar plant. Koerniche in Linnaea XXVII p. 603 took the hairy species as Linnaeus' E. setaceum and founded E. intermedium for the glabrous form on a sheet of Wight's, No. 2369. He considered that Linnaeus had been in error in quoting Rheede's figure for E. setaceum. Hooker in F.B.I, appears to have reverted to Steudel's conception of the glabrous plant for E. setaceum for he described the floral bracts as black and glabrous and founded the new species E. capillus-naiadis for the hairy heads. He also identified forms with glabrous heads and glabrous, not villous, receptacles as E. bifistiiloseum Van Huerck a West African species. Ruhland I.e. reinstated the hairy heads as of E. setaceum Linn., reducing Hooker's E. capillus-naiadis to that species, and restored E. intermedium Koern., at the same time confining E. bifistuloseum Van Huerck to West Africa. I find young heads often glabrous, though hairy when fully developed, and that it is impossible to determine with certainty whether the receptacle is grabrous or not, for it is often covered with short scales. I find also that the female petals vary in regard to the position of the gland, which may be well inside the margin as with other species or on it.

It seems however probable that there are in India only two species. E. setaceum L. with hairy and E. intermedium Koern. with glabrous bracts, and that other differences are casual variations. I have not seen Linnaeus type