100 BOTANY OF CONGO. 



Of the Primary Divisions, the Dicotyledonous plants 

 amount to 4 GO. 



The Monocotyledonous to 113 



And of the Acotyledonous, in which Ferns are included, 

 there are only 33 species. 



It is a necessary preliminary, with reference especially 

 to the first part of my subject, to determine whether this 

 herbarinm, \Yhich w^as collected in a period not exceeding 

 two months, and in a season somewdiat unfavourable, can 

 421] w^arrant any conclusions concerning the proportional 

 numbers of the three primary divisions, or of the principal 

 natural orders in the country in which it was formed. 



Its value in this respect must depend on the relation it 

 may be supposed to have to the Avhole vegetation of the 

 tract examined, and of the probability of the circumstances 

 under wdiich it w^as formed, not materially affecting the 

 proportions in question. 



Its probable relation to the complete Flora of the country 

 examined, can at present be judged of only by comparing it 

 with collections from different parts of the same coast of 

 equinoctial Africa. 



The first considerable herbarium from this coast, of which 

 we have any account, is that formed by Adanson, on the 

 banks of the Senegal, during a residence of nearly four 

 years. Adanson himself has not given the extent of his 

 collection, but as he has stated the new species contained in 

 it to be 300/ it may, I think, be inferred, that altogether it 

 did not exceed 600, wdiich is hardly equal to that from 

 Congo. Limited as this supposed extent of Adanson's herb- 

 arium may appear, it is estimated on the most moderate 

 calculation of the proportion that new species were likely to 

 bear to the whole vegetation of that part of equinoctial 

 Africa, wdiich he was the first botanist to examine ; allow- 

 ance being at the same time made for the disposition mani- 

 fested in the account of his travels, to reduce the plants 

 which he observed to the nearly related species of other 

 countries. 



From the herbarium and manuscripts in the library of 



' Fam. des Plant. ^, p. c.vvi. 



