Blake — A Revision of the Genus Viguiera 53 
Var. dilatatifolia: caule saepius densissime bifariamque tubercu- 
Br ichinpido-piloas; foliis ovatis vel late ovatis 5-14 em. longis 2.5- 
5.5 em. latis, saepius oppositis. — MEXICO: San Luis Porost: 
1830-2440 m., 1878, Parry & Palmer_458 (Type couu.: G., K., 
Mo., U. S.); Airis 28 Sept.—3 Oct. 1902, Palmer 145 (G., Mo., 
U. S.), 152 (G., Mo., U.S. 
Var. megacephala (Rob. & Greenm.), comb. nov.: pappo nullo, 
achenio glabro, caule bifariam hispido-piloso, foliis oblohee-dvate 
vel oblongo-lanceolatis 7.5-11 cm. longis 2.2-4.3 em. latis infra 
venulosioribus, ad et inter venas et venulas etiam minimas hispi- 
dulis. — Gymnolomia megacephala Rob. & Greenm. |. ¢. — MEX- 
ICO: GurrreRo: Between Tlapa and Ayusinapa, 1370-1740 m., 
13 Dec. 1894, LE. W. Nelson 2105 (Typ: G.). — Distinguished from 
the other forms of the species chiefly by its lack of pappus. 
7. V. PACHYCEPHALA (DC.) Hemsl. Stout, herbaceous, about 
2 m. high, the stem scatteringly sometimes densely villous-hispid 
in two lines, or densely tuberculate-hispid or -strigose, 14-headed. 
Leaves opposite below or sometimes nearly throughout, ovate- 
oblong to ovate or elongated-lanceolate, acute to obtuse at apex, 
rounded or cuneate into a short petioliform base, appressed-serrate 
or -serrulate, strongly venose below, densely tuberculate-hispid 
above with spreading or incurved hairs, beneath rather sparsely 
hispid mostly along the chief veins and gland-dotted between them, 
equally green both sides, 9.5-19 cm. long, (2-)3-4.7 cm. broad. 
Peduncles scarcely thickened below the head, stout, 4 em. long or 
~ more; heads 3.5-11.5 em. wide; disk 1.5-2.5 em. high, 2.5-3.5 cm. 
thick, convex in age. Involucre equalling the disk, 4-seriate, the 
inner phyllaries with chartaceous-membranaceous ampliated ob- 
tuse tip, densely and minutely tuberculate and more or less hispid; 
the two outer series subequal, herbaceous, indurated and ribbed 
at base, oblong, acute, densely hispid, trinerved, usually strongly 
involute. Rays about 18, oblong, 2.5-5 cm. long, 1-1.2 em. wide; 
disk-corollas puberulous below, 8 mm. long. Pales acute to 
acuminate, subglabrous, 8-13 mm. long. Achenes sparsely pubes- 
cent or glabrous, about 6 mm. long. Pappus present or absent; 
when present of 2 awns, widened below, 4.5-5 mm. long, and about 
10 squamellae, a pair of oblong larger ones (1 mm. long) at base 
of each awn, about 3 minute deltoid ones on each side of achene 
between them; whole pappus persistent. — Hemsl. Biol. Centr.- 

