Blake — A Revision of the Genus Viguiera 21 
Revisep Kry To VIGUIERA AND RELATED GENERA 
a. Achene not corky-margined, b 
b. is olucre 2-7 seriate, of more than 5 phyllaries, c, ; 
y deciduous, of two 
" Uaually mend or eaceous awns and very rarely short 
ate 

Onuieenee si ee vcd, HELIANTHUS L. 
c. Pappus “ol hg istent = Boa when present always in 
“espe 
d. “i bs or ve rarely shrubs, with large heads 
wollen enya Pte Ev pcb ce te oak tah TITHONIA Desf. 
d. Padiencles not swollen, e e. 
f. Pappus of awns a uamellae, the former of 
different hips and texture from ag latter 
and almost invariably much longer .. VIGUIERA HBK, 
f. Pappus of several subequal ianiwan nous- 
scarious scales ......... HYMENOSTEPHIUM Benth. 
é. ag none, 9. 
Herbaceo r rarely annuals 
(then with sagt eae Saylarise strictly herba- 
us) ; one species shrubby, with broadly 
v 
irvine AWGR es ri ev be casas VIGUIERA HBK. 
g. Annuals “with nae wand ax dorms ak a more . 
or less in ibbed at base; 
one nt gee a and with Cor 
wl 
lanceolate leaves ..... HYMENOSTEPHIUM Benth. 
b. oe Ong of 5 phyllaries; pappus of Hymeno- 
Pee Seats Mian hice cow ewes aeeroc caves ean 
IV. GENERAL MorpPHOLOGY 
Habit (and Habitat). The species of Viguiera seem to be practi- 
cally without exception plants of dry and usually elevated habitats. 
The data at hand are unfortunately too scanty to permit any 
significant correlation between habitat and general structure, but 
it may be stated in general terms that the majority of the species 
are mesophytic in character, a few pronouncedly xerophytic, and 
none hydrophytic. Most species are branched perennial herbs, a 
few annual, and some shrubs as much as 5-7 m. high. Occasionally 
the stem is simple, and rarely it is decumbent. 
Roots and Rootstocks. As is the case with many other genera of 
Compositae, the underground portions of the species of Viguiera 
have generally been neglected by collectors, and are known with 
efiniteness in not more than a third of the species. A presumably 
common type is that of V. dentata (supposed by Dr. Gray to be an 
annual or biennial, but shown by the abundant material now 
available to be clearly perennial), which has a thick or sometimes 
