Myriophyllum votschii

Detailed description

Dioecious perennial terrestrial herb, stems prostrate (rarely erect, forming tight cushions to 70 mm high), branching freely, rooting at nodes, forming clumps to 100 mm in diameter, glabrous. Leaves all opposite, entire, obovoid, 1.8-3.5 × (0.5-)0.7-1.1 mm, ± planar or slightly concave on upper surface, convex below, spreading or slightly upward-curving, glabrous.. Hydathodes absent. Rarely, in inundated plants, submerged leaves are formed, which are linear, 2.0 × 0.2 mm. Inflorescence a terminal spike with the unisexual flowers borne in the axils of opposite upper leaves indistinguishable from lower (sterile) leaves. Male and female flowers apparently borne on separate plants. Bracteoles linear, 0.5-0.7 × 0.1-0.2 mm. Hydathodes 0. Male flowers 4-merous, sessile, usually in axils of the uppermost pair of leaves only. Sepals 0. Petals 4, green at first, becoming white with a dark reddish spot at tip (rarely, completely dark red), hooded, non-unguiculate, 1.5-1.8 × 0.7-1.0 mm, reflexed at anthesis. Stamens 8; filaments 0.2-0.3 mm long, elongating to 0.8-11.0 mm at anthesis; anthers yellow, oblong, 1.2-1.3 × 0.4 mm, 4-celled, non apiculate or very weakly apiculate. Styles 0. Ovary vestigial. Female flowers 4-merous, sessile, in axils of upper 4-8 pairs of leaves. Sepals, petals and stamens 0. Styles 4, ± sessile, stigmas white, fimbriate, capitate. Ovary green, shortly cylindrical, 0.8 × 0.6-0.8 mm, longitudinally channelled between styles, rounded opposite styles, otherwise smooth. Fruit black, depressed-globular, 0.9-1.0 × 1.1-1.4 mm, suture between mericarps buff coloured; mericarps separating at maturity. Mericarps planar on inner faces, outer face convex, smooth or very weakly punctate, sometimes with a faint median longitudinal ridge.