328 PROCEEDINGS OF THE AMERICAN ACADEMY. 
cuneate base, thickish, glabrous and covered on both surfaces (under a 
lens) with very numerous dark glandular dots; blade 8 to 10 cm. long, 
2.3 to 3 cm. broad, pinnate-veined, the midnerve prominent beneath, 
grooved above; petiole 1.8 cm. long; the upper axils proliferous: in- 
florescence relatively small, 4 cm. broad, a trichotomous short-peduncled 
corymb ; involucral bracts 5 to 6 mm. long, viscid-pubescent upon the 
back, acutish: flowers 5; corolla, apparently white, about twice the 
length of the involucre, the tube viscid-puberulent: achenes smooth or 
nearly so, crowned with several narrow acute or subulate scales; more 
elongated awns apparently lacking. — Collected by C. & E. Seler in 
mountain woods between St. Carlos and St. Bartolo, Yantepec, Oaxaca, 
Mexico, 6 January, 1896, no. 1695. Well marked. Types in herb. 
Gray and herb. Royal Botanical Museum, Berlin. 
S. serraTA, Cav., var. arguta. Leaves narrowly linear, ascending 
or appressed, sharply serrate with incurved teeth: scales of the involucre 
attenuate toa dark subulate tip.— Collected by C. G. Pringle on the 
Cerro Ventoso above Pachuca, altitude 2,900 m., 18 August, 1898, no. 
7652. 
S. tephra. Ashy throughout with a close pulverulent pubescence 
not glandular: stems herbaceous, terete, purplish: leaves scattered, 
elliptical, obtuse, crenate-serrate, 3 cm. long, half as broad, 3-nerved, 
finely pubescent upon both surfaces, slightly paler beneath, mostly con- 
duplicate along the midrib, gradually narrowed to a petiole (1 em. in 
length) ; fascicles of smaller leaves on short or scarcely developed axil- 
lary shoots: inflorescence a moderately dense compound corymb ; its 
branches chiefly alternate, ascending, the lowet and longer about 8 em. 
in length, the heads densely clustered at their summits ; individual pedi- 
cels 1 to 2 mm. long; involucral scales merely acutish, cinereous- 
puberulent, without evident glands, green or purplish-tinged, 4 to 0 mm. 
long: flowers 5, about twice the length of the involucre: corolla-tube 
purplish, puberulent; limb white or nearly so: achenes black, lucid, 
4 mm. long, minutely roughened upon the angles; pappus of three awns 
(equalling the corolla) and 3 short blunt intermediate scales. — Col- 
lected by C. G. Pringle, Sierra de Pachuca, Hidalgo, altitude 2,925 m., 
_ 18 September, 1899, no. 8229. 
Piptothrix Goldmanii. Glabrous: stems terete, striate, purple; 
slightly lucid; internodes 6 to 8 cm. long: branches opposite: leaves 
deltoid-ovate, acuminate, serrate, 3-nerved from the shortly cuneate base, 
green and glabrous upon both surfaces, 8 to 10 cm. long, 6 to 8 cm. 
broad, thin but firm in texture, reticulated veins slightly prominent upo? 
