NO. 2 gentry: land plants 91 



flora of the Cape District is still in isolation. The climatic and edaphic 

 conditions of the peninsula, particularly north of the Sierra Giganta, 

 are not tolerable to the majority of the cape plants. Comparable habitats 

 on the mainland are still over 100 miles of water and coast away. 

 Equally significant to differences in the make-up of the cape flora and 

 the adjacent mainland are the numbers of species the two areas have 

 in common. Considering the long tenure of isolation for the cape flora 

 and the vicissitudes besetting diaspores across salt water, a higher endem- 

 ism could reasonably be predicted. It may be that the Cape District 

 was bridged to the peninsula during the middle Tertiary, allowing in- 

 gress of the aggresive Sinaloa element, which displaced some of the 

 insular population. However, whether cape Isolation dates from early 

 or late Tertiary, it is clear that genera have generally been conserva- 

 tive in species generation. The genesis of species does not appear to have 

 progressed nearly as rapidly in land plants as it has in land mammals 

 (cf. Zeuner, 1945:253-269, and 1946). 



In April of 1937 and in February of 1938 the Velero III made 

 stops in the Cape District. P. J. Rempel and E. Yale Dawson made 

 collections of land plants at San Jose del Cabo, and at Punta Frailes 

 and vicinity (Tables 1, 6). Their collections are enumerated below in 

 the catalogue of species for the California Gulf Region. 



Punta Frailes is among the least known of the localities visited 

 by the Velero III, the collections from there being the first. Punta 

 Frailes is a granite cerro that juts out into the mouth of the gulf on 

 the southeastern tip of the peninsula (Plate 5, fig. 13 ; pi. 6, figs. 14, 15). 

 Southwestward of the cerro is a sandy beach, where members of the 

 expedition landed and made collections. For causes which are still ob- 

 scure, this southeastern tip of the peninsula is the driest portion of the 

 Cape District. North of Punta Frailes is a mountain, known by the 

 natives as Sierra Victoria. This has been confounded by cartographers 

 (who have followed an early error) with Sierra Laguna which is the 

 main central mountain mass of the Cape District. There are no known 

 collections from Sierra Victoria. This mountain and the adjacent area 

 around Punta Frailes form a locality in need of detailed field work. 



Puerto Escondido is a small harbor with a neighboring rancho 

 lying at the foot of the precipitous Sierra Giganta scarp. Here the mas- 

 sive sedimentary formation is exposed and variously over-lapped by 

 volcanic lavas and breccias. A narrow plain bounds part of the shore, 

 in part the scarp rises high and spectacular out of the water (Plate 7, 

 figs. 16, 17). The climate is hot and arid, being on the lee side of the 



