Blake — A Revision of the Genus Viguiera 17 
Nos. 28 to 35 (excepting no. 31) of Robinson and Greenman’s re- 
vision form a related group of mostly large-headed species with the 
habit, foliage, and very distinct involucre of the subgenus A mphi- 
lepis of Viguiera. At the same time they provide the most cogent 
argument that could possibly be adduced for the proposed amalga- 
mation of most of the species of Gymnolomia with Viguiera, in the 
fact, already brought to attention by Robinson and Greenman, 
that two of their species (G. decumbens and G. megacephala var. 
simulans) are, omitting the achenes, absolutely identical in every 
detail with two species of Viguiera (V. Ghiesbreghtii and V. pachy- 
cephala: the latter was included by Robinson & Greenman in V. 
excelsa). Most of the other species show similar but less extreme 
resemblances to species of the same subgenus of Viguiera. Thus 
G. ensifolia is very close to V. angustifolia (H. & A.) Blake; G. 
Ghiesbreghtii Hemsl. and G. hypochlora Blake are very close to V. 
buddleiaeformis; while G. squarrosa and G. latibracteata have no 
very close analogues in Viguiera, but are clearly of the same group 
as the other species mentioned. The case of G. decumbens is espe- 
cially noteworthy. This species, which proves to be identical with 
the type of G. flava Hemsl. (not of Robinson and Greenman’s revi- 
sion) was described from a collection (no. 3263) made by Pringle 
at Tultenango in the State of Mexico. The specimen of this num- 
ber in the Klatt Herbarium, although so precisely similar in every 
feature that it might well have been cut originally from the many- 
stemmed root of the type in the Gray Herbarium, proved when 
later examined by Robinson and Greenman to have the pappus 
and achene-pubescence of Viguiera. The dissimilarities in the 
shape of the achenes indicated by Robinson and Greenman, how- 
ever, are not borne out by the comparison of mature fruit, and the 
differences in their pappus and pubescence, which as has before 
been noted are so closely linked as to be capable of consideration as 
a single character, are the only ones which can be found between 
the two specimens. Of importance, also, as further proving that 
in the case of Gymnolomia flava (G. decumbens) and Viguiera 
Ghiesbreghtii we have to do not with two wonderfully mimetic or 
convergent species of two different genera but with individuals of 
the same species whose sole significant difference is due to the pres- 
ence or absence of a single or two closely linked unit-characters, 
is the occurrence in both G. flava and V. Ghiesbreghtii of long-and- 
