192 FRANCIS RAM ALE Y 



crowned with plants. In low places, especially in the shelter of 

 high dunes, a fairly close plant community may occur, but else- 

 where there is always much bare ground. 



Such printed information^ as is available suggests that dunes 

 elsewhere along the Pacific Coast of the United States bear a 

 certain, often remote, resemblance in their vegetation to the 

 dunes at San Francisco. No extensive lists of plants have been 

 published, however, nor have the pioneers and later comers 

 been clearly distinghished. The species represented at San 

 Francisco, and to a large extent the genera, are different from 

 those of the Lake Michigan^ dunes or the dunes of Denmark*^ 

 and other European coasts. 



TYPICAL DUNE VEGETATION 



The pioneer plants are chiefly the sand verbena (Abronia 

 latifolia) and a low, spreading. Ambrosia-like herb, Franseria 

 chamissonis. Other plants are, however, responsible at times 

 for holding down mounds of greater or less size, as the sand 

 strawberry {Fragaria chilensis), dune tansy (Tanacetum cam- 

 phoratum), sand primrose {Oenothera cheiranthifolia) , the wild 

 cucumber {Echinocystis fahacea), and, close to the ocean, the ice 

 plant {Mesembryanthemum aequilaterale) . 



Marram grass (Ammophila arenaria) was introduced about 

 forty years ago and has been extensively planted since. In a 

 few places, close to the beach, it has become well established 

 but over the greater part of the dunes here described not a 



■• Crouch, Edward B., Notes on the ecology of sand-dune plants. Plant 

 World, 17: 204-208. 1914. 



Davy, Joseph Burtt, Stock ranges of northwestern California. Bureau of 

 Plant Industry, Bull 12. 1902. 



House, H. D., The sand dunes of Coos Bay, Oregon. Plant World, 17: 238- 

 243. 1914. 



Kellogg, F. B., Sand-dune reclamation of the coast of northern California 

 and southern Oregon. Proc. Soc. American Foresters, No. 1, 41-64. 1915. 



Olsson-Seffer, Pehr, op. cit. 



^ Cowles, H. C, Ecological relations of the vegetation of the sand dunes of 

 Lake Michigan. Bot. Gaz. 27: 95-117, 167-202, 281-308, 361-391. 1899. 



^ Warming, Eug., Oecology of Plants (English Edition, Oxford), 265-272. 

 1909. 



