228 Flora oj the Cape Region. [zoe 



their relation to the floras of neighboring regions, especially the 

 Mexican main land, is based upon 732 species. These are the re- 

 sult of collections made by Dr. Hinds of H.M.S. Sulphur in 1839, 

 at Cabo San Lucas; by L. J. Xantus de Vesey in 1859-1860, about 

 the same place; by Dr. Edward Palmer at La Paz in 1890, and by 

 the writer at various localities during three trips in 1890 and 1892. 

 Seventy-two species or nearly ten per cent, of the whole number 

 seem. to be endemic and future exploration together with the identi- 

 fication of unnamed specimens may increase this proportion, al- 

 though a more complete knowledge of the botany of Sinaloa and 

 Sonora will probably show that some plants now considered peculiar 

 to the Cape Region only appear so on account of our ignorance 

 concerning their distribution. Three hundred and sixty-two of the 

 Cape Region species are found growing on the peninsula from Mag- 

 dalena Bay and Comondu northward, and nearly one-half of this 

 number extend into Alta California; sixty-four of them are peculiar 

 to the peninsula. 



Mr. Hemsley in Biologia Centrali- Americana, iv, 139, considers 

 Mazatlan the southern limit of the North Mexican flora upon the 

 west coast; assuming this to be correct, nearly five hundred of the 

 species belong to that flora, and with few exceptions they all belong 

 to the flora of Sonora. 



The adjacent mainland, Sinaloa, has not been as well explored 

 botanically as Sonora, but judging from our scanty data the Mex- 

 ican part of the Cape Region flora bears much less resemblance to 

 it than to the more northern Sonora, and the flora as a whole is de- 

 cidedly that of Sonora and not an extension of that of Alta California 

 southward as has usually been svipposed. The few plants that 

 probably belong to a more southern flora are found along the 

 shore or in the southeast about San Jos^ and Miraflores. 



Some of these semi-tropical maritime and brackish-water plants 

 are found also on the southern end of the Peninsula of Florida. 

 Rhizophora, Conocarpus, Avicennia, Laguncularia, Iponi(za Pes- 

 caprcz and acetoscefolia and Sccevola Phiniieri are common to Amer- 

 ican tropical shores, and reach their northern limit at about the 

 same latitude on the Peninsula of Baja California as on that of 

 Florida. The number common to this region and Florida, how- 

 ever, is not large, and of about twenty-five having such widespread 

 distribution, some like Samolus ebracteahis and Ceiihmculus mini- 



