384 CALIFORNIA ACADEMY OF SCIENCES. 



pus and ZaiiscJineria , abound in sucli numbers, both of 

 species and individuals, as to force on us the strange 

 question of whether it was not from these, as from seed- 

 beds, that our mainland plants of the same genera were 

 •derived. There is one species of Dendromecon dispersed 

 widely up and down the Calif ornian mountain districts, and 

 this, until lately, was supposed to be a monotypical Pacific 

 North American genus. The hills of Santa Cruz are 

 embellished everywhere with a second strongly marked 

 species much larger than the mainland one; while Santa 

 Rosa, closely adjacent, furnishes the third. It is also 

 to be noted that Mr. Lyon reports the original species 

 as occurring on Santa Catalina, the island nearest the 

 €ontinent; so that the archipelago has all three species 

 of this genus, the mainland one only. In EschscJioUzia 

 closely allied to Dendromecon, we find two species, and 

 these exclusively insular, on Santa Cruz. In the order 

 of Crucifeixe the most characteristically Californian genus is 

 Tliysonocarpus, and its nearest relative is the Asian 

 lauscheria. Santa Cruz has two Thysanocarpi, both most 

 distinct from all species hitherto known, having their own 

 well marked habit, but, in fruit character, betraying the 

 closest aifinity for their Old World ally. 



The Cistacece are prevailingly an Old World order of 

 plants. There is but one representative of it on the 

 western coast of the North American continent. On Santa 

 Cruz this species abounds as nowhere else, and is there 

 associated with a second and new member of the same 

 genus, Helianthemum. 



In the vast order of the Legumhiosce, as in Bo.muicalacece, 

 there is exhibited a dearth both of s])ecies and individuals 

 of those genera which belong to the whole of North Amer- 

 ica, and a superabundance of them in such as are distinc- 

 tively Californian. One rarely meets with a Lathyriis, a 

 Vicia or an Astragalus, and the few and scattered individ- 

 uals in such genera occur only by the shores and in places 



