130 BOTANY OF CONGO. 



proportion, however, in equinoctial Africa would be the 

 more remarkable, as there is probably no part of the world 

 in which Compositse form so great a portion of the vege- 

 tation as at the Cape of Good Hope. 



RUBIACE^. Of this family there are forty-three 

 species in the collection, or about one fourteenth of its 

 Phsenogamous plants. I have no reason to suppose that 

 this proportion is greater than that existing in other parts 

 of equinoctial Africa ; on the contrary, it is exactly that of 

 Smeathman's collection from Sierra Leone. 



Baron Humboldt, however, states the equinoctial pro- 

 portion of Uubiacese to phsenogamous plants to be one to 

 twenty-nine, and that the order gradually diminishes in 

 relative number towards the poles. 



447] But it is to be observed that this family is composed 

 of two divisions, having very different relations to climate ; 

 the^rst, with opposite, or more rarely verticiUate, leaves 

 and intermediate stipules, to which, though constituting 

 the great mass of the order, the name Rubiacese cannot be 

 applied, being chiefly equinoctial ; while the second, or 

 Stellafce, having verticiUate or very rarely opposite leaves, 

 but in no case intermediate stipules, has its maximum in 

 the temperate zones, and is hardly found within the tropics, 

 unless at great heights. 



Hence perhaps we are to look for the minimum in num- 

 ber of species of the whole order, not in the frigid zone, 

 but, at least in certain situations, a few degrees only 

 beyond the tropics. 



In conformity to this statement, M. Delile's valuable 

 catalogue of the plants of Egypt^ includes no indigenous 

 species of the equinoctial division of the order, and only 

 five of StellatcB, or hardly the one hundred and sixtieth 

 part of the Phaenogamous plants. In M. Desfontaines' 

 Flora Atlantica, Rubiacese, consisting of fifteen SteUatee 

 and only one species of the equinoctial division, form less 

 than one ninetieth part of the Phsenogamous plants, a pro- 

 portion somewhat inferior to that existing in Lapland. 



1 Mor. 'Egypt. Illmtr. in Lescript. de VTSgypte, Hist, Nat, v. 2, p. 49. 



