166 BOTANY OF CONGO. 



together is equal at least to one-twelfth of the whole collec- 

 tion. The proportion, indeed, which these species bear to 

 the entire mass of vegetation on the banks of the Congo is 

 probably considerably smaller, for there is no reason to 

 believe that any of them are very abundant except Cyperus 

 Papyrus and Bombax pentandrum, and most of them 

 appear to have been seen only on the lower part of the 

 river. 



2nd. The relative numbers of the species belonging to 

 the primary divisions in the lists, are analogous to, and not 

 very materially different from, those of the whole herbarium ; 

 Dicotyledones being to Monocotyledones nearly as 3 to 1 ; 

 and Acotyledones being to both these divisions united as 

 hardly 1 to 16 : hence the Phsenogamous plants of the lists 

 alone form about one-thirteenth of the entire collection. 



The proportions now stated are very different from those 

 existing in the catalogue I have given of plants common to 

 New Holland and Europe;^ in which the Acotyledones 

 form one-twentieth, and the Phsenogamous plants only one- 

 sixtieth part of the extra-tropical portion of the Flora ; 

 while the Monocotyledones are to the Dicotyledones as 2 

 tol. 



( The great proportion of Dicotyledonous plants in the 

 lists now given, and especially in the first two, which are 

 altogether composed of American species, is singularly at 

 variance with an opinion very generally received, that no 

 well established instance can be produced of a Dicotyle- 

 donous plant, common to the equinoctial regions of the old 

 and new continent. 



3rd. The far greater part of the species in the lists are 

 strictly equinoctial ; a few, however, have also been observed 

 in the temperate zones, namely, Agrostis Virginica, belong- 

 ing, as its name implies, to Virginia, and found also on the 

 shores of Van Diemen's Island, in a still higher latitude; 

 Cyperus Papyrus and articulatus, Nymphsea Lotus, and 

 480] Pistia Stratiotes, which are natives of Egypt ; Glinus 

 Jotoides of Egypt and Barbary ; and Flagellaria indica, 



' flinders' Vmj. 2, p. 592. {Ante, p. OS.) 



