Prionosciadium macrophyllum Coult. & Rose

Prionosciadium macrophyllum Coult. & Rose, Proc Wash. Acad. 1: 151. 1900.
Plants stout, 1-4 m. high, the foliage and inflorescence somewhat scaberulous; basal leaves deltoid in general outline, excluding the petioles 6-12 dm. long, 2-ternate-pinnate, the leaflets broadly lanceolate to ovate, acute at the apex, subcordate at the base, 5-14 cm. long, 1.5-8.5 cm. broad, petiolulate, pinnately incised to divided with coarsely dentate to pinnatifid, ovate or oblong lobes, the rachis unwinged; upper cauline leaves opposite, bipinnatifid, with short oblong sheaths', inflorescence compound-umbellate, the short verticillate branches each bearing a whorl of peduncles; peduncles slender, 1.5-9 cm. long, each subtended by a pair of leaves and usually bearing a solitary leaf or bract; involucre wanting, or of 1-several filiform bracts 5-10 mm. long; involucel of several filiform bractlets 3-6 mm. long, shorter than the flowers and fruit; fertile rays 4-9, spreading or divaricate, subequal, 2-3 cm. long; fertile pedicels 2-5, 2-7 mm. long; calyx-teeth obsolete; flowers greenish-white, the ovary glabrous; fruit oval, truncate or retuse at the apex, retuse at the base, 10-13 mm. long, 7-1 1 mm. broad, glabrous, the dorsal ribs prominent, the lateral broadly winged, the wings broader than the body; oil-tubes small, 1-3 in the intervals, 6-12 on the commissure; seed channeled under the intervals, the face involute.
Type locality: "Rocky bank of river. Falls of Juanacatlan, Jalisco," Pringle 3889. Distribution-. Sonora and Durango to Jalisco (Nelson 4554, Pringle 8632).