ROBINSON AND GREENMAN, — MEXICAN PLANTS. 51 
white wool: leaves all radical, runcinately pinnatifid, glabrous or nearly 
so, petioled, thin, acutish; lobes 5 to 7, mucronulate-dentate: stems 
about a foot high, slender, dark colored, quite smooth, bearing a few 
scattered minute appressed subulate bracts and at the summit 2 or 3 
heads on slender ascending branches: heads 9 lines long, about 18- 
flowered: scales of the involucre in 5 series, obtuse, flattish (not thick- 
ened nor firm in texture), dark colored, ciliated, otherwise glabrous, the 
inner ones 5 lines long: flowers lilac in dried state, 7 to 8 lines long (in- 
cluding the achenes). — Collected by C. G. Pringle, in shade, at Tomellin 
Cafion, Oaxaca, altitude 3,000 feet, 1 December, 1895, no. 5966. Closely 
related to P. nudicaulis, Gray, but haying a more numérously seriate in- 
volucre with thinner flatter scales, and flowers nearly twice as large. 
Soncuus aspsr, Vill. Although so generally distributed as a weed 
upon waste heaps, etc., this plant does not appear to have been noted 
in Mexican lists. It has been collected at San Diego, Chihuahua, by 
Hartman, and near the city of Oaxaca, by Nelson, no. 1353. 
