Prionosciadium madrense S. Wats.

Prionosciadium madrense S. Wats. Proc. Am. Acad. 23: 275. 1888
Prionosciadium durangense Coult. & Rose, Proc. Wash. Acad. 1: 151. 1900.
Plants stout, 1 m. high, the inflorescence and foliage somewhat scaberulous or glabrous; basal leaves deltoid in general outline, excluding the petioles 2-3 dm. long, 1-2-ternate to 1-2-pinnate, the leaflets lanceolate to ovate, acute or acuminate at the apex, cuneate at the base, 1.5-5 cm. long, 0.5-2 cm. broad, distinct or the distal confluent, again 1-2-pinnatifid, the rachis unwinged; petioles 1-1.5 dm. long, broadly inflated-sheathing; upper cauline leaves opposite, bipinnatifid with obsolete sheaths; inflorescence of several series of opposite or whorled branches terminating in simple terminal peduncles, or with lateral peduncles also; peduncles slender, 2.5-10 cm. long, each subtended by a pair of leaves; involucre wanting, or of a single filiform bract about 5 mm. long; involucel of several filiform, puberulent bractlets 3-6 mm. long, about equaling the flowers but shorter than the fruit; fertile raj's 6-12, spreading or divaricate, unequal, 1.5-3.5 cm. long; fertile pedicels 2-6, 4—6 mm. long; calyx-teeth obsolete; flowers purple, the ovary glabrous; fruit oblong, rounded at the apex, retuse at the base, 8-10 mm. long, 5-8 mm. broad, glabrous, the dorsal ribs prominent, the lateral broadly thin-winged, the wings equaling or broader than the body; oil-tubes small, 3-5 in the intervals, about 7 on the commissure; seed slightly channeled under the intervals, the face involute.
Type locality: "On ledges of a river canon near Guerrero, Chihuahua," Pringle 1251. Distribution: Chihuahua and Sonora to Durango (Gentry 1527, Townsend &• Barber 153).