GEOGRAPHICAL BOTANY. 393 



the Euphorbiaceae, Polygonaceae, and Onagrariae are more 

 abundant than the remaining families : the entire Cali- 

 fornian herbarium, however, only includes about 200 sp. 

 The arid and frequently sandy soil is physiognomically 

 characterised by different Cacti, 2 of which are distributed 

 exactly as far as S. Pedro, and accurately define the 

 extent of the flora. At Magdalene Bay, other tropical 

 forms also begin to appear with the mangrove forests in 

 considerable numbers, which are mixed in the text with 

 the steppe- plants of Lower California, but which must of 

 course be distinguished geographically from them. The 

 Euphorbia-shrubs only are common to both the districts 

 of the peninsula; nevertheless, the species which pre- 

 dominate within and without the tropic are different. 

 Magdalene Bay appears to form a well-defined floral limit 

 northwards. Together with Cape Lucas, it yielded one 

 half of the plants contained in Hinds's Californian herba- 

 rium. But whether this tropical southern point of the 

 peninsula forms a distinct and third botanical district, or 

 should be considered as belonging to that of the western 

 coast of Mexico, remains at present undecided, inasmuch 

 as most of the plants collected here have not yet been 

 described. The following are the families of the latter 

 collection which contain the largest number of species : 

 Synantheraceae Q), Euphorbiaceae Q), Leguminosae (], 

 Graminaceae, Solanacese, Malvaceae, and Nyctagineae. 

 New genera from California, by Bentham : Stegnosperma 

 (Phytolaccaceae),/$'m^^te andEremocarpus (Euphorbia- 

 ceae), Helogyne, Perityle, Coreocarpus, Acoma, Amauria 

 (Synantheracete), Eriodictyum (Hydroleaceae). F. D. 

 Bennett in a short time collected some 70 sp. on the 

 tropical south point of California ; they have not yet been 

 made known (Narrative of a Whaling Voyage. London, 

 1840, vol. ii, p. 18). He saw there columnar Cacti, 

 from 15' 20' in height, and speaks of the luxuriance 

 of the forests and of numerous succulent and bulbous 

 plants. 



Martens and Galeotti have continued their papers on 



