Conium sphaerocarpum Hilliard & B.L.Burtt

Biennial herb up to 2 m tall; taproot stout, white, up to 8 mm diam.; stem erect, up to 10 mm diam., immaculate, simple below, divaricately branched above, internodes mostly 70-100(-200) mm long, much shorter on the inflorescence branches. Radical leaves wanting at flowering; stem leaves ± deltoid in outline, 80-300 mm long, pinnately decompound, petiole 1/2-1/3 total leaf length, progressively shorter upwards; inflorescence leaves sessile except for sheathing base; pinnae well spaced, the distance between them roughly equal to their length, pinnules cut 1/2-2/3 of the way to the midrib, lobes ± oblong, 1-3 mm broad, toothed, tips acute or subacute, mucronulate. Umbels compound, many in a spreading cymose panicle, terminal umbel always hermaphrodite, laterals often functionally male, all 25-40 mm in diam. at anthesis, hemispherical; peduncles usually ±5-25 mm long, laterals often somewhat longer, glabrous; bracts generally 3, lanceolate, up to ±3 x 2 mm, membranous, white, tinged green. Umbellules (4-)8-9(-11), hemispherical, ±5-8 mm in diam.; peduncles ±5-20 mm long, shortest in the functionally male, outermost spreading horizontally, glabrous or sparsely scabridulous; bracteoles (1-)3(-5), broadly lanceolate, up to ±1-2 x 1 mm, shortly or deeply united at base, membranous, white, tinged green; pedicels ±13-20, of varying lengths, glabrous or sparsely scabridulous. Calyx wanting. Petals 1-1.25 mm long, suborbicular with a short claw and short indexed acute tip, white. Stamens 5, filaments incurved. Stylopodium somewhat conical, with a thick fleshy undulate rim; styles ±0.75 mm long, spreading; ovary campanulate, ±0.75 x 0.75 mm. Mericarps each 2-2.5 x 1 mm, obscurely 5-ribbed, broadly elliptic to ± hemispherical in transverse section; endosperm smooth in outline; pericarp blackish-brown.