4. Nechamandra Ann. Sci. Nat., Bot., ser. 3, 11: 78 (1849).
Taxon Description
Perennial submerged herbs. Roots fibrous. Stems elongated, fragile, extensively branched. Leaves submerged, alternate, densely clustered near ends of stems, linear, partly sheathing at base, apex acute, margin minutely serrulate, parallel veins present, lacking a prominent midvein. Plants dioecious. Male inflorescence pedunculate, numerous flowered. Spathe oblong, membranous, bifid at apex. Flowers actinomorphic, unisexual. Male flowers small. Sepals 3, petaloid, ovate. Petals 3, subequal to sepals. Stamens 2 or 3, opposite to sepals; filaments slender, very short. Female spathe tubular, sessile, 1-flowered. Female flowers similar to male ones. Ovary oblong, extended into a beak at apex. Fruit an achene, ovoid-oblong or linear. Seeds small, numerous, oblong.
Taxon Statistics
Worldwide one species in S and SE Asia.
1. Nechamandra alternifolia (Roxb. ex Wight) Thwaites, Enum. Pl. Zeyl. 332 (1864).
Vallisneria alternifolia Roxb. ex Wight, Bot. Misc. 2: 344 (1831).
Perennial, submerged herbs, 12–23(–40) cm. Roots fibrous, ca. 5 cm. Stems elongated, fragile, extensively branched. Leaves densely clustered near ends of stems, linear, 1.5–2 cm X 2–4 mm, base partly sheathing, apex acute, margin minutely serrulate, veins parallel, lacking a prominent midvein. Flowers actinomorphic, unisexual. Male inflorescence pedunculate, numerous flowered. Spathe oblong, ca. 5 mm, membranous, bifid at apex. Male flowers small. Sepals 3, petaloid, ovate, 0.5–1 X 0.5–0.7 mm. Petals 3, subequal to sepals. Stamens 2 or 3, opposite to sepals; filaments slender, very short. Female spathe tubular, ca. 5 mm, sessile, 1-flowered. Female flowers similar to male ones. Ovary oblong, extended into a beak at apex. Fruit a fleshy berry like capsule, ovoid-oblong or linear, 5–5.5 X 3.5–0.5 mm. Seeds small, numerous, ca. 1 mm long, oblong with reticulate seed coat.
Distribution: Nepal, Assam-Burma, S Asia, E Asia and SE Asia.
Altitudinal range: 600–900 m.
Ecology: Ponds, lakes, slow moving rivers and channels.
Flowering: September. Fruiting: October.
Description of flowers and fruit characters of Nechamandra alternifolia is based on the other article (Christopher and Lüönd, 1982), floras (Qingfeng et al. 2010), protologue text, and digital image of holotype (BM).