Blake — A Revision of the Genus Viguiera 27 
In the section Diplostichis (t. 2. f. 11-13) the involucral char- 
acters are much as in the Dentatae, although the ovate tendency of 
the base of the phyllary is less pronounced. In Heliomeris (t, 2. f. 
14) the 2-seriate scarcely graduated involucre is composed of 
strictly herbaceous mostly lanceolate phyllaries, sometimes vittate 
but never ribbed. 
Unlike the groups so far discussed, which are represented south 
of Panama only by three species of sect. Diplostichis in Colombia, 
Venezuela, and Ecuador, the section Paradosa (t. 2. f. 15-26), in- 
cluding nearly half the species of the genus, is exclusively South 
American, with its great centers in Brazil and in the Andes from 
Keuador to Bolivia. Its subdivisions, based chiefly on involucral 
characters almost continuously intergradient, are in some sort 
parallel to those of the Mexican species without ever exactly 
matching them, and all its species are undoubtedly of one common 
origin without any but a distant connection with the Mexican 
forms inning with the series showing the simplest involucral 
features, the Tenwifoliae, we find a 2-seriate subequal involucre of 
lanceolate to oblong phyllaries which are subher} us throughout 
or only very slightly indurated at base in age. In the Revolutae 
(t. 2. f. 15) the 3—5-seriate involucre is distinctly graduated, and 
its phyllaries are more or less distinctly ribbed below, although any 
differentiation into base and apex of diverse texture is very obscure. 
A similar involucre is shown by the Grandiflorae (t. 2. f. 16-17). 
The large series Aureae (t. 2. f. 18-26), however, shows a gradual 
accentuation of the differentiation between the proximal and distal 
portions of the phyllaries, until in some of its species one finds a 
condition scarcely distinguishable from that found in the Bractea- 
tae. In the group of species centering about V. aurea (t. 2. f. 18-19) - 
the strongly graduated phyllaries are distinctly drier in texture at 
the base but not prominently indurated, and the ribbing when 
present is inconspicuous. In the V. pazensis group the situation 
is nearly the same, although in V. Pflanzii (t. 2. f. 20) and V. 
lanceolata the indurated base becomes prominent in some speci- 
mens, as it is to a greater or less degree in the V. fusiformis group 
(t. 2. f. 22). In V. Szyszylowiczii (t. 2. f. 21) there is very little 
differentiation in the phyllaries, and the general appearance is that 
of the Mexican series Grammatoglossae. V. acutifolia and V. austra- 
lis (t. 2. f. 24) have lanceolate phyllaries with distinctly indurated 

