NO. 2 GENTRY : LAND PLANTS 117 



phy, (4) wetter latitudes, and degree of endemism to be heightened with 

 these same factors plus greater duration of isolation. However, the 

 available figures show us scarcely no such correlations. For example, al- 

 though Tiburon Island is the largest and one of the highest, it has fewer 

 species (80) than the much smaller island of Carmen (100). Catalina 

 with an area of 44 square km has only 14 species, while San Francisco 

 with an area of 4.5 square km has 30 species of plants. Such figures are 

 meaningless for phytogeographic analysis, because the islands have been 

 so incompletely collected. There is no published meteorological data for 

 any of the islands. 



The most striking aspect of the island floras is the apparent lack of 

 divergent evolution. Endemism is at an all space low. This may be ex- 

 plainable on the basis of island youthfulness, or the tj^pes of migrules 

 and the agencies that bear them. Or it may be that lack of endemism 

 is in large part apparent rather than actual, since the summer-fall flora 

 is unknown. Can we expect more endemism to have evolved out of the 

 sub-tropical element than has appeared already in the temperate one? 

 The most certain deduction that can be made at present is that all 

 analysis will be tenuous until the island floras are individually and com- 

 pletely known and the physiography of the gulf well dated. The tables 

 are presented at this time not for a complete reference, but rather as a 

 summing up of our present knowledge and to accentuate the need for 

 additional field work. Our ignorance regarding the island floras is nearly 

 enormous. 



CATALOGUE OF COLLECTIONS 



POLYPODIACEAE 



Adiantum Capillus-veneris L., Sp. PI. 1096. 1753. 



Puerto Escondido, February 11, Dawson 1090. 



Cosmopolitan in warm temperate regions. In western North America 

 it is known from southern California south to the Sierra Giganta in 

 southern Baja California and central Sinaloa, Mexico. 



Gramineae 



Anthephora hermaphrodita (L.) Kuntze, Rev. Gen. PI. 2:759. 

 1891. 



Punta Frailes, Cape District, February 16, Dawson 1122. 



Widely distributed in tropical and subtropical America; type from 

 Jamaica. 



