NO. 2 GENTRY : LAND PLANTS 67 



well nigh impossible. Trees are abundant on the weather side of the 

 island but on the south and east sides they are mostly confined to can- 

 yons, and were smaller than on the north slopes. They were nowhere 

 seen over forty or fifty feet in height, though usually covering consider- 

 able area with their broad spreading branches." 



Hanna and party found an upland section of red hills with flattened 

 and denuded vegetation, which they attributed to a cataclysmic wash- 

 out by a tropical cloud burst. On the south slopes of the mountain 

 above Grayson Cove, they found grass, cactus, and some shrub adventive 

 over the area that Grayson (1871:295) had fired 53 years earlier. 

 The montane forest is found only in the upper reaches of the canyons — 

 "In the canyon were many strange trees, flowers, epiphytic plants and 

 orchids." Birds were excessively abundant and droves of sheep were 

 met with here and there all the way. ''The forests in the canyons were 

 so dense that the sunlight rarely penetrated to the ground ; hence mosses, 

 lichens, ferns, and orchids, were abundant on the trees and branches. 



'Trom the top we were able to study the best means of approaching 

 the mountain and found it unquestionably to be from Grayson Cove. 

 But that route does not pass through any such interesting country as 

 we had traversed on the ascent. Wooded canyons are absent on the 

 south side but are abundant on the north, east and west. Between them 

 brush covered ridges radiate outward like spokes of a wheel" (Hanna, 

 1926:48, 54, 57). 



The flora of Socorro is the richest of the Revilla Gigedo Islands. 

 The larger and higher area of more diversified terrain is accompanied 

 by a more highly evolved indigenous flora. The five collectors who 

 have visited the island have given us records of 102 species of vascular 

 plants. Table 3. Barkelew's collection of 70 numbers is the only one 

 made in the summer and he apparently failed to reach much of the 

 higher richer flora of the interior. To Mason goes credit for first hav- 

 ing brought the rich potentialities of the montane forest to our atten- 

 tion by his collections. Late summer and fall collections would add 

 more species and genera to the island flora. And, as Johnston wrote 

 (1931 :15) "the most important botanical work now awaiting attention 

 on the islands concerns not species so much as the vegetation and the 

 living plant. The past collectors on the islands have been quite satisfied 

 in making a single collection of each species found on each of the islands. 

 No attempt has been made to make repeated collections either to show 

 variation of the plants or their distribution on particular islands. There 

 is almost nothing on record regarding the abundance, habits, stature, 



