APPENDIX. No. V. 445 
feet in height, with cylindrical stem and branches, was observed, planted on 
the graves of the natives near several of the villages; but of this, which may 
be what Captain Tuckey has called Cactus quadrangularis in his Narrative 
{p. 115) there is no specimen in the herbarium. 
COMPOSIT A. It is unnecessary here to enter into the question whether 
this family of plants, of which upwards of 3000 species are already known, 
ought to be considered as a class or as an order merely ; the expediency of 
subdividing it, and affixing proper names to the divisions, being generally 
admitted. The divisions or tribes proposed by M. Cassini, in his valuable 
dissertations on this family appear, to be the most natural, though as yet they 
have not been very satisfactorily defined. 
The number of Composite in the collection is only twenty-four, more than 
half of which are referable to Helianthew and Vernoniacee of M. Cassini. 
The greater part of these are unpublished species, and among them are five 
new genera. The published species belong to other divisions, and are chiefly 
Indian: but one of them, Ageratum conyzoides, is common to America 
and India; the Struchiwm (or Sparganophorus) of the collection does not 
appear to me different from that of the West Indies; and Mikania chenopo- 
difolia, a plant very general on this line of coast, though perhaps confined to 
it, belongs to a genus of which all the other species are found only in America. 
Baron Humboldt has stated * that Composite: form one sixth of the Phzeno- 
gamous plants within the tropics, and that their proportion gradually decreases 
in the higher latitudes until in the frigid zones it is reduced to one thirteenth. 
But in the herbarium from Congo Composite form only one twenty-third, 
and both in Smeathman s collection from Sierra Leone and in Dr. Roxburgh’s 
Flora Indica, a still smaller part, of the Phzenogamous plants. In the northern 
part of New Holland they form about one sixteenth; and in a manuscript 
catalogue of plants of equinoctial America, in the library of Sir Joseph Banks, 
they are nearly in the same proportion. 
In estimating the comparative value of these different materials, I may, in 
the first place, observe that though the herbarium from Congo was collected in 
the dry season of the country, there is no reason to suppose on that account that 
the proportion of this family of plants, in particular, is materially or even in 
* In op. citat. 
