Rhizomatous, usually glabrous, perennial herb; stems slender. Leaves 3-foliolate; leaflets sessile, dull or shiny green, glabrous, obovate-cuneate to suborbicular, 1-4 (-5) mm long, entire or with 2-3 shallow crenate teeth; petioles glabrous or, very rarely, with a few retrorse hairs near blade, slender, (2-) 5-30 (-80) mm long; stipules scale-like. Umbels simple, 1-2-flowered; peduncles equalling or somewhat shorter than leaves; bracts scale-like, fused, c. 0.5 mm long; flowers hermaphrodite, usually sessile, rarely shortly pedicellate, c. 2-3 mm diam. Fruit brown or black, 1.2-1.8 × 1-1.2 mm, more or less rounded on dorsal edge; ribs obscure of slightly raised.

Rhizomatous, usually glabrous, perennial herb; stems slender. Leaves 3-foliolate; leaflets sessile, glossy green or tinged bronze, glabrous, broadly obovate-cuneate, (1-) 3-6 (-8) mm long, with 1-3 lobes, and each lobe with 1-4 shallow crenate teeth; leaflets produced early in the growing season and leaflets of reduced plants often entire or with 2-3 shallow crenate teeth; petioles glabrous or, very rarely, with a few retrorse hairs near blade, slender, (2-) 15-50 (-100) mm long; stipules scale-like. Umbels simple, (1-) 2-7-flowered; peduncles about equalling leaves; bracts scale-like, usually fused, sometimes free almost to base, 0.5-1 mm long; flowers hermaphrodite, shortly pedicellate, c. 2-3 mm diam. Fruit light brown, (1.5-)2-2.5 × (1-)1.2- 1.8 mm, rounded on dorsal edge; ribs slightly engraved into surface of mature fruit.

Folia 3-foliolata; foliola glabra, obovato-cuneata, 1-8 mm longa, plerumque 2- vel 3-lobata, lobis crenatis, raro integris vel simpliciter crenatis; petioli plerumque glabri, raro pilos paucos retrorsos laminam versus gerentes. Umbellae simplices, (1-) 2-7-florae; flores hermaphroditi circa 2-3 mm diametro. Fructus 1.5-2.5 mm latus, 1-1.8 mm longus; costae in fructus maturi superficiem leviter sulcatae. Differt a H. tripartita foliolis glabris, fructus costis manifeste sulcatis; differt quoque a H. hydrophila foliolis plerumque magis profunde lobatis et umbellulis plerumque flores plures gerentibus.

Rhizomatous and stoloniferous perennial herb; stems glabrous, slender. Leaves 3-foliolate; leaflets sessile, shiny green, glabrous to sparsely pilose above, usually moderately pilose below (rarely glabrous), broadly obovate-cuneate, 2-6 mm long, with 1-3 lobes, and each lobe with 1-4 shallow dentate teeth, teeth with a small cartilaginous point; petiole slender, (3-) 10-30 (-50) mm long, always with a few retrorse hairs near blade, otherwise glabrous; stipules scale-like. Umbels simple (1-) 2- 10 (-12)-flowered; bracts scale-like, free or shortly fused at base, c. 0.5 mm long; flowers hermaphrodite, subsessile, c. 1-2 mm diam. Fruit brown, 0.8- 1.2 × 0.8-1.2, acute on dorsal edge; ribs raised, slender, prominent.