440 MR. G. BENTHAM ON COMPOSITE. 
closely resembles the above-mentioned Asiatic W. (Cyathophora) 
urticifolia, as to be frequently mixed with it in collections. 
Blainvillea is represented in tropical Africa and Asia by three or 
four species, one of them proposed as a distinct genus, but which 
are all closely allied to a common east tropical American weed, 
the typical B. rhomboidea, Cass.; they seem, however, to be rather 
representative than identical species. Two other common American 
weeds (both nearly allied to, but sectionally or, according to some, 
generically diverging from B. rhomboidea), Blainvillea biaristata, 
DC., and Eleutheranthera ruderalis, Sch. Bip., are not represented 
in Africa. Aspilia was the generic name originally given to a 
Madagascar plant, which, on a comparative examination, has ap- 
peared to me to be strictly congener as well with the African Co- 
ronocarpi as with a number of American, chiefly Brazilian, plants, 
referred by different botanists to various genera, including the 
whole of the genus Anomostephium, DC. Amidst these several 
names, Dupetit Thouars's Aspilia has the right of priority. The 
genus thus formed is divisible into three not very well-defined 
series, of which two are exclusively Brazilian; the third, extend- 
ing in Ameriea from Brazil to Mexico, also ineludes some of the 
African species, though no one species is identical in the two 
continents ; the Masearene and one or two Afriean ones eannot be 
exactly included in either of the American series. The tropical 
American genera Zexmenia, twenty species, and Oyedea, twenty- 
two species, neither of them represented in Africa, are very 
closely allied to Wedelia, as is also the insular Lipocheta, consist- 
ing of ten Sandwich-Island and one Galapagos species (Macrea, 
Hook. f., united with Lipocheta by A. Gray). 
Sclerocarpus was originally established for a tropical African 
plant now known to extend into tropical Asia, remarkable for the 
receptacular palez completely enclosing the disk-achenes and 
hardened round them, so as to appear to form part of them. Pre- 
cisely the same structure was observed in some tropical American 
species, never compared with the African one, but distributed into 
various genera, although one of them (Gymnopsis uniserialis, 
Hook.), if not exactly identical with S. africanus, is so closely 
allied to it as to be strictly representative. The genus thus con- 
solidated comprises one tropical African and nine American spe- 
cies, chiefly from the Mexican region, but extending also 
into tropical South America. A similar structure is observable 
in the American genus Montanoa, of about fourteen species, 
ranging from Columbia to the Mexican region. 
