cells dehiscing laterally, connective produced, apiculate. Female flower: Perianth short, cupular, hyaline. Carpels 2–6, sessile; styles long or short; stigma large, obliquely peltate, crenate; ovule solitary, pendulous, orthotropous. Ripe carpels usually 3 or 4, sessile or stalked, curved, oblong or oblong-reniform, slightly compressed, tubercled or crenate or smooth on the back, beaked by the projecting style. Seed pendulous; testa membranous; embryo cylindric, the cotyledonary end bent into a short coil.
An almost cosmopolitan genus of 4 or 5 closely allied species, probably all forms of one.
1. Z. palustris, Linn. Sp. Plant. 969.—Stems very slender, much branched, leafy throughout, often forming dense masses, 3–14 in. long. Leaves opposite or subwhorled, very slender, ½–3 in. long, filiform, flat. Flowers sessile or very shortly pedicelled. Fruiting carpels 3 or 4, about 112 in. long, stipitate or almost sessile, curved, smooth or very obscurely crenate on the back; styles from half to almost as long as the carpels.—Hook. f. Fl. Nov. Zel. i. 237; Handb. N.Z. Fl. 280; Kirk in Trans. N.Z. Inst. xxviii. (1896) 498.
North Island: Auckland—Abundant in the Waikato River, from Taupiri downwards, also in Lakes Waikare, Whangape, and Waihi, Kirk! T.F.C. Hawke's Bay—Tangoia Lagoon, Colenso! South Island: Otago—Waikouaiti Lagoon, Petrie! December–May.
The Waikato specimens have the carpels sessile or nearly so, and decidedly turgid; in those from Hawke's Bay and Otago they are distinctly stipitate, and with longer styles. Both forms have the back of the carpel smooth or nearly so.
5. LEPILÆNA, J. Drummond.
Very slender submerged vrater-plants; stems filiform, branched. Leaves alternate or the floral ones opposite, filiform, sheathing at the base; sheaths broad, stipular. Flowers minute, axillary, diœcious or rarely monœcious, solitary within the dilated sheathing bases of a pair of floral leaves. Male flowers shortly pedicelled. Perianth very minute, of 3 hyaline scales. Anthers 2 or 3, united by their backs and forming a solid column resembling a single anther; each anther 2-celled, dehiscing longitudinally. Female flowers sessile or shortly pedicellate. Perianth of 3 hyaline segments longer or shorter than the carpels. Carpels 3, distinct, sessile or shortly stipitate, narrowed into a short or long style; stigma oblong or spathulate; ovule solitary, pendulous. Ripe carpels usually 3, oblong, coriaceous, indehiscent, tipped by the persistent style. Seed oblong; testa membranous; embryo with a thick obtuse radicle and tapering involute cotyledonary end.
A small genus of 4 species, 3 of which are Australian, one of them said to extend to New Zealand; the remaining one is endemic in New Zealand. In Engler's "Naturlichen Pflanzenfamilien" the genus is merged with the Mediterranean Althenia.
