A small genus, not uncommon in the north temperate zone. In the Southern Hemisphere its sole representative is the following species, which is found in both Australia and New Zealand.
1. S. antipodum, Graebner in Allg. Bot. Zeitschr. iv. (1899) 33.—Stems slender, erect, 1–2 ft. high. Leaves very long, the lower radical ones usually far surpassing the inflorescence, 110–15 in. broad, flattish above, acutely and prominently keeled beneath, tip acute, lower portion expanded into a long but rather narrow sheath. Inflorescence simple in small specimens, but usually with 1–3 slender flexuous branches bearing male heads alone or very rarely with a single female below the males; main rhachis with 2–4 distant female heads below, and 3–12 more closely placed male ones above; the lower portion of the inflorescence with long leafy bracts. Filaments of the male flowers long, considerably more than twice the length of the scales. Stigma narrow, elongate. Ripe fruit about ⅙ in. long, broadly obovoid, mucronate with the short thick persistent style.—S. angustifolium, R. Br. Prodr. 338 (not of Michx.); Benth. Fl. Austral. vii. 160; Col. in Trans. N.Z. Inst. xvi. (1884) 339. S. simplex, Hook. f. Fl. Nov. Zel. i. 238, and Handb. N.Z. Fl. 277 (not of Huds.).
North Island: Watery places from the North Cape to Wellington, not uncommon. South Island: Near Picton, J. Rutland! Maru. December–March .
Also in Australia, from Queensland to Victoria. S. subglobosum, Morong in Bull. Torrey Club, xv. (1888) 76, t. 79, f. 1, said to have been collected at the Bay of Islands by the American Exploring Expedition, is probably the same, and, if so, Morong's name will take precedence.
Order LXXXVII. LEMNACEÆ.
Minute gregarious floating water-plants, without distinct stems or true leaves, consisting of green scale-like fronds free from one another or 2–3 cohering by their margins, either rootless or more generally giving off 1 or several capillary rootlets from the undersurface. Flowers very seldom produced, most minute, placed in clefts on the edges of the frond, or sunk on its surface, naked or enclosed in a spathe, usually a single female with 1 or 2 males by its side. Perianth wanting in both sexes. Male flower: Stamens 1 or 2; filaments short; anthers 1–2-celled. Female: Ovary sessile, 1-celled, narrowed into a short and stout style; stigma simple; ovules 1–7. Fruit a somewhat fleshy utricle, with 1 or several seeds; albumen fleshy or wanting; embryo straight, axile.
An order of 2 genera and 20 species, found in still waters in all countries, both temperate and tropical. It contains the smallest of all known flowering-plants, all of them being of exceedingly simple structure, and very seldom found in flower.
