Sparganium subglobosum

Detailed description

Glabrous, summer-green, rhizomatous, perennial herb of aquatic or fertile swamps. Rhizomes ascending, long and slender. Stems usually partially submerged in water, silt, mud or peat. Plants at flowering up to 1 m tall. Leaves most arising from base, somewhat spongy to firmly fleshy; 0.3-1 m tall, up to 10 mm wide, more or less erect; sheathing base channelled; lamina dark green, green to yellow green, linear to narrow linear, deltoid to subrhomboid in cross-section, longitudinal nerves distinct; incomplete cross walls occasionally evident apex obtuse to subacute. Peduncle up to 2 mm diameter, usually shorted than leaves; lower bracts foliaceous, long, often with basal third to one half clasping peduncle. Inflorescence simple or sparingly branched; main axis bearing up to 20 globose capitula; lower 1-6 female, rest male; lateral axis often bearing only male capitula, sometimes with up to 2 female capitula below; capitula sessile and either strictly axillary or without bracts. Flowers white. Male capitula up to 15 mm diameter, flowers numerous; stamens 3 mm long, filaments much > perianth; anthers conspicuous, white, oblong. basifixed, up to 3 times as long as broad. Female capitula to 18 mm diameter, flowers up to 60; perianth scales 4-8, the inner ones smaller; ovary 4 mm long, sessile, narrowly fusiform, unilocular, ovule solitary, pendulous; style short; stigma oval, c.1/2 style-length. Fruit 6 x 3 mm, dry, indehiscent, externally hard, internal spongy; dark green to yellow-green, sessile, obovoid, style base forming a hard, prolonged beak.