GREENMAN. —NEW ANGIOSPERMS FROM MEXICO. 115 
BIDENS TERETICAULIS, DC., var. sordida. Leaves mostly simple 
and undivided, rarely deeply 3-parted, sordid-pubescent upon both sur- 
faces more densely so beneath: outer scales of the involucre rusty 
tomentose. — Costa Rica. Thal des rio Segando, Hoffmann, no. 383 
(hb. Gr.) ; foréts de la Mala Via au Copey, April, 1898, Ad. Tonduz, 
no. 12,284 (hb. Gr., and hb. Inst. Phys.-Geog. Cost. Ri.). 
Arnicastrum, n. gen. of Composite (Helenoidee). Heads _heter- 
ogamous, many-flowered. Involucre campanulate; bracts 2-3-seriate, 
the outer herbaceous. Receptacle convex, naked. Ray-flowers yellow, 
ligulate, 2—3-dentate, fertile, epappose; mature achenes numerously 
ribbed. Disk-flowers with a rather slender tube dilated above into 
an equally 5-toothed limb: pappus of numerous somewhat unequal 
barbellate bristles: achenes slightly compressed, 4-angled, many-ribbed. 
Herbaceous perennials with opposite leaves and rather large heads. 
A. glandulosum. Stems erect, 3 to 5 dm. high, mostly branched 
from the base, striate, hispidulous-pubescent, and above especially on the 
usually long peduncles bearing long-stipitate purplish glandular hairs: 
leaves sessile, subamplexicaul, 83—5-nerved from the base, narrowly lan- 
ceolate, 2 to 8 cm. long, 3 to 15 mm. broad, entire or sparingly denticu- 
late, hispidulous-pubescent on both surfaces: heads about 1 em. high, 
including the rays 8 to 4.5 em. in diameter; outer involucral scales 
oblong or oblong-ovate, 10 to 12 mm. long, 5 to 8 mm. broad, obtuse, 
entire, hirtellous-pubescent on the outer surface ; the inner scales mostly 
longer, sometimes acuminate, membranous: ray-flowers about 10; tube 
2 to 3 mm. long, externally pubescent; rays elliptic-oblong, 1.5 cm. 
long, 6 mm. broad: disk-flowers numerous: pappus-bristles unequal, the 
longer equalling or exceeding the tube of the corolla: achenes hirtel- 
lous-puberulent above, many-ribbed. — Mexico. State of Chihuahua : 
Sierra Madre, 21 June, 29 July, 1899, #. W. Nelson, no. 6102 (hb. Gr., 
and hb. U. S. Nat. Mus.) ; Sierra Madre, near Colonia Garcia, altitude 
2450 m., 26 July, 1899, Townsend & Barber, no. 169 (hb. Gr.). 
Var. vestitum. Outer scales of the involucre7 to 9 mm. long, and 
closely covered with purplish glandular hairs; otherwise like the species 
proper. — Mexico. State of Durango: 48 km. north of Guanacevi, 
altitude 2450 to 2775 m., 18 August, 1898, #. W. Nelson, no. 4778 
(hb. Gr., and hb. U. S. Nat. Mus.). In general habit Arnicastrum glan- 
dulosum, and the variety vestitum resemble certain species of Arnica more 
particularly in the opposite leaves and the rather long internodes. In 
the technical characters of the head, however, they seem to have their 
nearest affinity with Juwmea, Beria and Whitneya. 
