Citation: E. Robertson, sp. nov.

Synonymy: Not Applicable

Common name: None

Description:
Dioecious rhizomatous submerged perennial herb of fresh or brackish water; rhizomes 0.5-1.5 mm diam., much-branched, bearing at each node a membranous amplexicaul scale c. 2-5 mm long, 2-10 unbranched roots and an erect leafy shoot to 75 cm tall; leaves alternate; sheath membranous, 4-5 mm long, ligule to 4 mm long, deeply cleft; blade frequently held at right angles to the erect stem, flat, entire, 1-3 (sometimes to 6) cm long, 0.5-1.2 mm broad, apex more or less truncate with a short mucro or narrowed to an acute tip; squamules filiform c. 0.5 mm long.

Male flowers in leafy shoots c. 15-45 cm tall; several flowers each in the axil of a modified erect leaf borne in a tight cluster; shortly pedicellate at first, pedicel elongating to c. 1 cm at anthesis; perianth-segments 3, entire or irregularly lobed, united at the base; anther of 6 pollen-sacs c. 2 mm long; female flowers borne on slender erect shoots to 75 cm tall; each flower axillary, borne on a short pedicel c. 5 mm long (elongating to 1-2 cm in fruit) usually closely appressed to the axis with flowers usually extending beyond the leaf sheath; subtending leaves erect; perianth-segments 2.5-3 mm long, membranous, elliptic, frequently becoming scarious and white, apex 2-fid or dentate; carpophore 0.1-0.2 mm long at first; styles projecting beyond the perianth; stigmas narrow-elliptic to funnel-shaped, margin sparsely dentate.

Fruit an achene, dark-brown, more or less oblong, 1.5-2.5 mm long, 2 or 3 times as long as broad, somewhat verrucose, usually with 1-3 longitudinal ridges; carpophore in fruit thickened and elongated, projecting the fruit well beyond the perianth-segments.

Distribution:  In fresh and brackish inland lagoons. Probably more widespread.   Vic.; Tas. Conservation status: native Flowering time: Flowers and fruits: July — Feb. (probably most of the year).

SA Distribution Map based on current data relating to specimens held in the State Herbarium of South Australia

Biology: A distinctive species recognised by its robust habit, the relatively short leaves usually held stiffly more or less at right angles to the erect stem, leaf blade c. 1 mm broad and fruit verrucose projecting well beyond the perianth-segments on an elongated carpophore.

Taxonomic notes: Species nova propria, habitu robusto, foliis brevioribus plerumque ad angulum 90° a caule erecto rigide patentibus, lamina circa 1 mm lata, fructuqne verrucato in carpophoro elongato suffulto ultra tepala exsertissimo notatur.

Author: Not yet available