—41— 



strictly endemic plants, some of which are without other even 

 generic American representatives. Thus this extreme western 

 fringe of the continent has no less than four endemic species of 

 Lavatera, a genus unknown elsewhere in' all America, North or 

 South. The monotypic Lyonothaninus Jloribundus Gray, a saxi- 

 fragaceous tree, is found on three of the islands, and nowhere else 

 in the world; and Erythea edulis Watson, a palm of a genus in 

 which there is but one other species, is confined to the island of 

 Guadaloupe. 



The third group, and much the smallest, contains a few plants 

 which on the islands attain a more northern extension of their 

 range than on the continent. An example of these is Lycium 

 Streetsii Gray, a species of Lower California, which is represented 

 on Santa Catalina Island. On the same island is found Crosso- 

 soma Califomica Nutt. , a species hardly distinct from that 

 which inhabits Arizona and the Colorado Desert. These give 

 emphasis to the undoubted fact that the relationship of the island 

 floras, like that of the flora of the neighboring continental regions, 

 is with the south, and not with the north. 



Such being the geographical position and the climatic condi- 

 tions of the islands, and such the affinity of their floras, we find 

 in Poly podium Scouleri the single exception: a northern plant 

 which has been able to extend its limits far south of that which 

 it has reached on the mainland, and into a different phytogeo- 

 graphical area. 



The fern has been reported from three of the islands. In 1889 

 Dr. Yates found it on Santa Cruz Island, "growing luxuriantly 

 among the projecting fragments of volcanic rocks, at the mouth 

 of one of the most interesting caves on the island."* Dr. Yates 

 has favored me with specimens of a subsequent collection, made 

 in August, 1893. These are characteristic, but smaller than most 

 mainland specimens of this fern. 



Two records have been made from Santa Catalina, one by 

 Mr. Brandegee, f and the other by Airs. Trask;{. yet the presence 

 of the fern on this island, while not improbable, is not certain. 

 There are no specimens of it from the island in Mr. Brandegee' s 

 herbarium, or in the herbarium of the California Academy of 

 Sciences; while Mrs. Trask's specimens of the plant, both as rep- 



♦Yates, L. G., Bull. Santa Barb. Soc. Nat. Hist.. i:q. 

 tBrandegee, T. S. Zot\ 1:115, 

 *Trask. Blanche. Eryth., 7:142. 



