Prionosciadium simplex Mathias & Constance

Prionosciadium simplex Math. & Const. Bull Torrey Club 68: 255. 1941.
Plants slender, 3-8 dm. high, glaucous and glabrous except for the scaberulous inflorescence; basal leaves deltoid in general outline, excluding the petioles 8-15 cm. long, biternate, the leaflets oblong to ovate-lanceolate, obtuse or abruptly acute at the apex, truncate at the base, 1.5-2.5 cm. long, 8-15 mm. broad, distinct, petiolulate, finely serrate and often with 2 lateral lobes at the base, glaucous beneath, the rachis unwinged; petioles slender, 3-5 cm. long, the sheaths elongate, oblong, with a scarious margin; cauline leaves alternate, reduced upward with a conspicuous oblong sheath; inflorescence of a single terminal umbel or with some lateral branches below; peduncles slender, 7-12 cm. long; involucre wanting; involucel of several, lanceolate or ovate-lanceolate, acuminate, purplish bractlets 3-6 mm. long, shorter than the fruit; fertile rays about 4—11, spreading-ascending, unequal, 1.5-4.5 cm. long, scaberulous; fertile pedicels 2-6, 2-4 mm. long; calyx-teeth obsolete; flowers purple; ovary glabrous; fruit ovoid, truncate at the apex, rounded at the base, 6-8 mm. long, 3.5-5 mm. broad, glabrous, the dorsal ribs filiform, the lateral thin-winged, the wings narrower than the body.
Type locality: "On mountains near Miquihuana, Tamaulipas," 7000-9000 feet, Nelson 4478 Distribution: Known only from the type locality (Stanford &• al. 677).