490 MR. G. BENTHAM ON COMPOSITAE. 
local areas; Helichrysez are, with few exceptions, limited to South 
Africa, Australia, and the Mediterranean region of the Old Wortd: 
The delimitation and subdivision of the genus Gnaphalium has 
much puzzled all synantherologists, and is still in a very unsatis- 
factory state. Among the species now generally admitted to belong 
to it are some which by Lessing and De Candolle were established 
as a genus of Mutisiaee: ; and the differences observable, whether 
in habit or structure, are not much in accord with the geographical 
distribution. The genus as a whole is cosmopolitan, though rather 
more temperate or mountainous than tropical ; and the two prin- 
cipal groups into which it might be divided as to habit inflorescence 
and involueres, represented, for example, by G. polycephalum and 
G. uliginosum respectively, are both to be found over the same 
area; whilst G. luteo-album, which closely connects the two groups, 
is ubiquitous. Weddell proposed the division into two genera 
founded on the pappus, of which the sete are quite free and sepa- 
rately caducous in Gnaphalium, united at the base in a ring and 
falling off altogether in Gamocheta: and this appears at first 
sight very plausible, and accompanied by some difference in the 
involucre; but upon further investigation it is found to separate 
species like G. purpureum and G. indicum, so closely allied that 
they are found mixed together in most collections, whilst it unites 
into one genus G. polycephalum, G. lavandulaceum, and G. uligi- 
nosum, species evidently the most remote in affinity of the whole 
series. It would seem, therefore, that Weddell’s divisions can 
only be taken as somewhat artificial sections, and that if we 
attempt any more natural although vaguely characterized groups 
we must recognize three as very generally diffused, those above- 
mentioned as typified by G. polycephalum and G. uliginosum with 
theintermediate G. luteo-album under Eugnaphalium, and that exem- 
plified by G. purpureum and G. sylvaticum under Gamocheta, and 
about five other groups confined to special geographical areas :— 
1, two or three Andine species (Mexican or South-American) 
belonging to Eugnaphalium, but remarkable for their involucral 
bracts radiating as in Chionolena, which they also resemble in 
habit; 2, Lucilia (including Bellos), a Chilian or south Andine 
group, differing from other Gamochete chiefly in their longer nar- 
row involucres; 3, Merope, dwarf tufted or prostrate Andine plants, 
with the involucral bracts more spreading after flowering than in 
Lucilia, to which A. Gray unites them ; 4, Omatotheca, a Europxo- 
Asiatic and North-American Alpine plant, dwarf like the Meropes, 
