Diagnostic ²

"Erect, branched, semi-aquatic herbs; stem green, sparsely puberulous. Leaves alternate, elliptic-lanceolate, base attenuate and decurrent on the petiole at base, margins serrulate-denticulate, apex acute or acuminate; petiole to 2.5 cm long. Heads axillary, sessile, cluster of 4-5, c. 5 mm across, globose, white, homogamous. Involucre in 4-5 series, outer smaller and inner larger, triangular to oblanceolate, acuminate, greenish, margins scarious and hairy. Receptacle convex, pitted. Florets all tubular, without palea, 4-5 mm long, bisexual. Calyx of three white, 0.5 mm long, acute scales united variously, persistent. Corolla 2-3 mm long, white, tube narrow, lobes 5, spreading glandular. Stamens 3; filaments filiform, white. Ovary c. 1.5 mm long; stigma bifid, purple. Achenes c. 1.5 mm long, triangular, blackish."

Sources and Credits

1. (c) Smithsonian Institution, National Museum of Natural History, Department of Botany, some rights reserved (CC BY-NC-SA), https://collections.nmnh.si.edu/services/media.php?env=botany&irn=10384992
2. (c) India Biodiversity Portal, some rights reserved (CC BY), http://eol.org/data_objects/26340429

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