NO. 2 GENTRY : LAND PLANTS 65 



I.e. p. 36). It has three distinct hills, the eastern being the highest 

 and reaching about 321 meters above sea level. "The hills are rounded 

 by erosion and show few canyons of any size. Over most of the island 

 there is a deep reddish brown soil that suggests antiquity. Undoubtedly 

 erosion now takes place very slowly; the rainfall is slight but the island 

 is w^ell covered with vegetation" (Johnston 1931 :25). The few habitats 

 of two sand beaches on the south side, rocky sea cliffs, mesa, slopes, and 

 hill tops are not indicative of a rich flora. There is no permanent source 

 of fresh water. Hanna (1926:39) mentions a pool of brackish water at 

 the east end behind a sand beach, which he thought might be potable 

 during the rainy season. 



The island appeared to Hanna to have been very little altered by 

 human interference. Such spots are so rare on the extra-polar portions 

 of our little earth that his remarks on this point are quoted in full 

 (1926:33). 



"No mammals of any kind were found on the island. Fortunately, 

 the place has never been inhabited, even by temporary residents; hence 

 those curses of the isles to the northward, mice, cats, and goats, have 

 not become established. In fact, Clarion Island is one of the few places 

 remaining which has not been modified in some way through the agency 

 of man. The original 'balance of nature' still obtains. We know of only 

 one case of the introduction of any kind of life. In 1903 the California 

 Academy of Sciences sent an expedition to these islands and during the 

 course of the work on Socorro Island some paroquets were captured 

 alive. Mr. E. W. Gifford, a member of the expedition, told us that 

 some of these birds were liberated on Clarion Island. We saw no sign 

 of them during our stay and it is supposed that they perished through 

 lack of fruit which constitutes their chief food on their native island." 



The natural vegetation is dominated by thorny shrub under 15 feet 

 in stature. Hanna noted "One species of plant — , a shrub about 15 feet 

 high and the nearest approach to a tree found" (1926:38). One of the 

 most abundant shrubs was Opuntia occidentalis, which "grows very 

 luxuriantly in a broad zone around the shore line and more or less in 

 patches to the top of the island. Intertwined in it everywhere are dense 

 growths of vines" (1926:32). For ingress to the interior it was neces- 

 sary to cut trails through the dense spiny thickets. Other dominant 

 thorn shrubs include Zantroxylon fagara, and Euphorbia anthonyi is 

 probably the shrub, the fruits of which stained the parties' clothing. 

 On the tops of the island they found large areas covered with grass. 



