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 Plora ; while the Monocotyledones are to the Dicotyledones as 2 to 1.
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 i)art 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 Straliotes, which are natives of Egypt ; Glhius lotoides of Egypt and Barbary ; and Flagellaria indica^
^ Flinders' Voy. 2, f 3U2. [Ante, p. 08.)
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