DISTRIBUTION OF TRIDES. 417 
in the inflorescence tending towards that of Monarrhenes. 
5. Eyrea, with three species, all Australian, is a form diverging in 
another direction, in its broader or hemispherical, often solitary, 
capitula and narrower involucral bracts, but apparently better 
placed as a section of Pluchea than as a distinct genus. 
In America three small genera, scarcely more divergent from 
Pluchea than some of the foregoing, but each with a very special 
geographical range, may still be kept up as distinct ; these are :— 
1, Sachsia, three Cuban species more distinct from Pluchea in 
habit than in character; 2, Rhodogeron, a single species, also 
from Cuba, with the female fiorets almost ligulate, an exception 
to the whole subtribe; and, 3, Zessaria, five species limited to 
western temperate or Andine America from Chili to California, 
has not the tropical geographical character of Pluchea, but is 
elosely allied to the less tropical Asiatic forms of Pluchea both in 
habit and in eharaeter, whilst in indumentum and in the con- 
sistence of the involucral braets it shows some approach to the 
Gnaphaliee. Stenachentum, consisting of two or three Brazilian 
species, although hitherto included in Pluchea, is much more 
distinct than any of the foregoing, especially in its long achenes, 
exceptional in the subtribe. 
Two Old-World forms of limited geographical range diverge 
rather more prominently from Pluchea, to which they bear, 
nevertheless, much general resemblance—Pterigeron, five Aus- 
tralian species, and Vanothamnus, one East-Indian species, both 
with anomalous corollas, the former showing an approach to 
those of some Athrixiez, the latter to those of Mutisiacem. This 
Asiatic monotypic genus, with two equally monotypic Australian 
genera, Thespidium and Coleocoma, unite the Pluchean involucre 
and flowers with a much modified, reduced, or evanescent pappus; 
and the latter two Australian plants have, moreover, a very pecu- 
liar habit and inflorescence. 
Epaltes, a genus of about nine species, is spread over the same 
wide tropical and subtropical area as Pluchea itself. With the 
essential characters of the subtribe Plucheine:e, it bears a general 
resemblance, in habit and pappusless achenes, to the Vernonia- 
eeous Ethulia, with which genus it has often been confounded 
through a total neglect of the principal floral characters. The 
genus as a whole is a very natural one, although the species of 
each region have been raised into separate genera upon characters 
which scarcely deserve more than a specific rank. Thus Pachy- 
2n2 
