Arracacia arguta (Rose) Mathias & Constance

Arracacia arguta (Rose) Math. & Const. Bull. Torrey Club 68: 121. 1941.
Museniopsis arguta Rose, Contr. U. S. Nat. Herb. 8: 336. 1905. Tausckia drudeophytoides F. Macbr. Contr. Gray Herb. 56: 33. 1918.
Slender, caulescent, branching, from a stout taproot, 3-6 dm. high, glabrous throughout; leaves ovate to deltoid in general outline, excluding the petioles 5-20 cm. long, ternately or ternate-pinnately dissected, the leaflets ovate-lanceolate, acute at the apex, cordate at the base or the terminal cuneate, petiolulate to sessile, 2-5 cm. long, 1.5-3 cm. broad, sharply mucronateserrate to more or less incised or lobed, glabrous or very slightly roughened on the veins; petioles slender, 5-14 cm. long, narrowly sheathing at the base; cauline leaves greatly reduced upwards, the uppermost opposite, sessile, entire or ternate with lanceolate or linear, elongate divisions and narrow sheaths; inflorescence cymosely branched, the peduncles alternate or verticillate, slender, 5-12 cm. long; involucre wanting; involucel of several small, linear, entire bractlets 2-4 mm. long, about equaling the flowers but shorter than the fruit ; fertile rays 3-8, slender, spreading-ascending or rather strict, unequal, 2-3 cm. long, or shorter in the smaller lateral umbels; pedicels short and stout, spreading-ascending, 1-3 mm. long; flowers yellow, the petals oval; stylopodium low-conic, the styles very short, spreading; carpophore 2-cleft about onehalf of its length, rigid; fruit oblong-oval, 3-4 mm. lon-j, 2-3 mm. broad, glabrous, tapering slightly at the apex, rounded at the base, the ribs prominent, narrow, acute; oil-tubes small, several in the intervals and on the commissure; seed-face slightly sulcate.
Type locality: "On a rocky hillside about the waterfall near El Oro," Michoacan, Pringle S612 (erroneously published as "6812" and given as the State of Mexico). Distribution: Known only from the type locality.