Prionosciadium filifolium Coult. & Rose

Prionosciadium filifolium Coult. & Rose, Proc Wash. Acad. 1: 152. 1900.
Prionosciadium tenuifolium Coult. & Rose, Proc. Wash. Acad. 1: 152. 1900.
Plants stout, 0.5-1.5 m. high, more or less scaberulous throughout; basal leaves deltoid in general outline, excluding the petioles 3-5 dm. long, ternately or ternate-pinnately decompound, the ultimate divisions linear to filiform, 1-4 cm. long, 2 mm. or less broad, entire, the rachis unwinged; upper cauline leaves opposite, ternately decompound with inconspicuous sheaths; inflorescence of several verticils of peduncles; peduncles slender, 2.5-5 cm. long, subtended by a pair of leaves, scaberulous at the summit; involucre wanting; involucel of several linear bractlets 5-8 mm. long, shorter or longer than the flowers but shorter than the fruit; fertile rays 8-10, spreading, 1.5-3 cm. long; fertile pedicels 1-4, 2-4 mm. long; calyx-teeth obsolete; flowers yellowish-white, the ovary and very young fruit puberulent; mature fruit not seen; immature fruit ovoid-oblong, rounded at the apex, retuse at the base, 5-6 mm. long, 4 mm. broad, the dorsal ribs unwinged, the lateral broadly winged; oil-tubes 3 or 4 in the intervals, 7 or 8 on the commissure.
Type locality: "On the road between Colotlan and Bolanos," Jalisco, Rose 2834. Distribution: Jalisco (Rose 2510).