Apium prostratum Labill. ex Vent.
Procumbent to ascending, terrestrial perennial, not rooting at nodes. Lvs pinnately 3-foliolate to 1-2-pinnate; ultimate segments broadly or narrowly ovate to deltate, usually lobed and crenate, c. 5-30 mm long; upper stem lvs similar to lower and basal lvs, but often reduced and 3-foliolate or simple. Umbels compound, usually sessile or subsessile, lf-opposed; rays 2-10-(15); bracts and bracteoles 0. Fls numerous, white. Fr. broadly ovoid, 1.5-2.5 mm long; ribs broad and spongy.
N.: Northland ( subsp. prostratum var. prostratum); N.; S.; St.; K., Ant. ( subsp. prostratum var. filiforme (A. Rich.) Kirk); Ch. ( subsp. denticulatum P. Short).
Also indigenous to Australia and some Pacific Is.
Coastal rocks, muds and gravels.
The corky ribs of the fr. (Fig. 11) distinguish A. prostratum from the 2 naturalised spp.
A. prostratum is variable in overall size, stoutness of plants and in lf form. Slender forms are often named A. filiforme in N.Z. and stout forms A. australe. Short (op. cit.) distinguished the Australasian A. prostratum from the S. American A. australe Thouars.