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 Tiickey has called Cactus quadrangularis in his Narrative 

 (p. 115) there is no specimen in the herbai'ium. 



COMPOSITiE. It is unnecessary here to enter into the question whether 

 this family of plants, of which upwards of 3001) species are already known, 

 ought to l:e 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 ap{)ear, to be the most natural, though as yet they 

 have not been very sati-facti.rily defined. 



The number of Composita; in the collection is only twenty-four, more than 

 half of which are referable to HeliantltecB and Venioniacew 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 The greater part of these are unpublished species, and among them are five 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 coiiyzoldes, is common to America 

 and India ; the Sinichium (or Sparganophorus) of the collection does not 

 appear to me different from that of the West Indies; and Mikan'ia 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 Compo^itte form one sixth of the Phasno- 

 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 Compositaj form only one twenty-third, 

 and bolh in Smeathman's collection from Sierra Leone and in Dr. Roxburgh's 

 Flora Indica, a still smaller part, of the Phaenoganious plants. In the northern 

 part of New Holland they form about one sixteenth ; and in a manuscinpt 

 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, obsi. rve 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, diet. 



