NO. 2 GENTRY I LAND PLANTS 45 



seria, A triplex, Viguiera, and Encelia are common. Succulents are repre- 

 sented in Agave and cacti and semi-succulents by such shrub and tree 

 forms as Euphorbia misera and Pachycormiis discolor. The sclerophyl- 

 lous shrubs of Rhus and Siminondsia appear to be prevalent and Greene 

 mentions (1888:197) two evergreen shrubs, Gilia Veatchii and Harfor- 

 dia fruticosa, ' Vhich grow on these lower hills in sufficient quantities to 

 impart an appearance of verdure." To Greene the most conspicuous tree 

 was the corpulent xerophyte, Pachycormus discolor, endemic to Baja 

 California and adjacent islands. A scrubby juniper, Juniperus cerrosi- 

 anus, he reported as growing throughout all elevations. Towards the 

 summits of the mountains, Pinus muricata cedrosensis is accompanied by 

 Arctostaphylos bicolor. 



George O. Hale and Lee Haines, as two students of botany at the 

 University of California at Los Angeles, spent six weeks in the early 

 spring of 1939 on the island and made an ecologic study of the vegeta- 

 tion. Hale (1941) reported about 97% of the island is covered through 

 all elevations with Desert Shrub. It has a uniform growth as a regularly 

 dispersed open formation of lov/ bushy shrubs spotted with large shrubs 

 or dwarf tree forms; among the latter, that of Pachycormus discolor 

 being the most ubiquitous. He found differences in composition between 

 the higher elevations and the lower elevations, and divided the Desert 

 Shrub accordingly into ''High Altitude Desert" (650 to 1300 meters 

 elevation) and "Low Altitude Desert" (below 650 meters elevation). 

 As dominants of the former he listed Eriogonmn fasciculatum, Pachy- 

 cormus discolor, Haplopappus propinquus, and Franseria camphorata 

 leptophylla and for the latter he listed as most abundant Harfordia 

 fruticosa, Euphorbia misera, Pachycormus discolor, Franseria chenopodi- 

 folia, and Encelia calif ornica asperifolia. 



The only other low altitude assocation he reported is ''Maritime 

 Dune Scrub," occupying a small dune area on the southwest coast. 

 Dominated by A triplex julacea and Frankenia Palmeri, it is also charac- 

 terized by Brodiaea, Abronia, Achyronchia Cooperi, Oenothera, and Ly- 

 cium Andersoni. 



The highland vegetation, other than High Altitude Desert Shrub, 

 occupies limited areas at middle and high elevations. 



A Closed Cone Pine Forest (250 to 900 meters elev.) occurs in 

 two widely separated areas on western and northern slopes, in the 

 central and northern parts cf the island. The pines usually occur in 

 pure stands and have an average mature stature of about 50 feet. Hale 



