90 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13 



est), and Pine-oak Forest. Grasslands are lacking except for a few 

 small mountain meadow-lands, as *'La Laguna" on Sierra Laguna and 

 an obvious Increase in grasses in the Pine-oak Forest generally. Thorn 

 Forest is not as well developed as It is on the adjacent mainland, being 

 but a brief transitional element between Desert Shrub and the more 

 prevalent Short-tree Forest of the slopes and canyons which comprise 

 the greater part of the area. Except for the minor role of Thorn Forest 

 and the lack of a well defined Oak Grassland, the vegetations show a 

 comparable alignment to that of southern Sonora. The variance may be 

 attributable to the islandic origin. Views of Cape District vegetation 

 are shown In Plate 6. 



The flora of the Cape District is more tropical than temperate. 

 Brandegee's floristic survey of the eighteen nineties (1891, 1892, 1894, 

 1901), listed 104 species of Leguminosae, 103 species of Composltae, 

 and 52 species of Gramineae. While this is incomplete, he did collect 

 generally through all elevations and his collections appear fairly repre- 

 sentative of these three major groups of angiosperms. The respective 

 ratios of these groups per given area are often instructive about floristic 

 relations. The light showing of grasses is comparable to that found In 

 Thorn Forest and Short-tree Forest on the adjacent mainland. Generally, 

 the Composltae are more numerous through temperate regions, while 

 Leguminosae dominate the floras of tropical regions. The fact that le- 

 gumes equal or exceed the composites in numbers of species in the Cape 

 District attests Its tropical affinities. The number of genera common to 

 the cape and the adjacent mainland is far greater than those common 

 to the cape and the northern part of the gulf region, as may be expected. 

 In North America the following genera of the Leguminosae in the Cape 

 District have their centers of area in southern Mexico and Central 

 America. Acacia, Mimosa, Pithecolobium, Lysiloma, Desmanihus, Albiz- 

 zia, Caesalpinia, Cassia, Bauhiniaj Indigofera, Tephrosia, Coursetia, 

 Benthamantha, Sesbania, Nissolia, Aeschynomene, Erythrina, Galactia, 

 Phaseolus, Haematoxylon, and Leucaena. This list is Incomplete, but 

 much longer than we would cite for those having northern centers of 

 areas, as Astragalus, Lupinus, Lotus, and Trifolium, and which are 

 not strongly represented In species in the Cape District. Three endemic 

 genera {Coulter ella, Clevelandia, and Faxonia) are known from the 

 Cape District, and over 100 endemic species and varieties have been 

 described (Interpreting their occurrences along the Sierra GIganta as 

 postinsular migrations). 



Actually, except for the flora of the Desert Shrub formation, the 



