Flora of New Zealand Series

Usually glabrous perennial, forming small to large patches; stems slender. Lvs 3-foliolate; leaflets sessile, dull or shiny green, obovate-cuneate to suborbicular, 1-4-(5) mm long, entire or with 2-3 shallow crenate lobes; petiole usually glabrous, very rarely with a few retrorse hairs near blade. Umbels simple, 1-2-flowered; peduncles ± = or < lvs. Fls usually sessile, rarely shortly pedicellate. Fr. glabrous, 1.2-1.8 × 1-1.2 mm, ± rounded on dorsal edge; ribs obscure or slightly raised.

N.: common in lowland to montane areas; S.: scatttered localities in E. and S. lowland to montane areas.

Endemic.

Swamps, lake and stream edges, coastal lagoons, especially in periodically submerged turf vegetation.

H. hydrophila is similar to H. sulcata, but can be distinguished by the generally smaller, less incised leaflets, and the smaller frs with less sulcate ribs. It was treated by Allan (1961) as H. tripartita var. hydrophila (Petrie) Cheeseman.