$6 Prof. Schouw on the Geographical Distribution of Palms* 
The palms are, in part, gregarious, as, for example, Chame- 
rops humilis , which covers considerable districts in the south of 
Europe, and in Northern Africa ; Mauritiajlexuosa , and others, 
which form the palm woods in South America. They occur, 
however, in part, also solitary, such as Oreodoxa Jrigida. The 
species do not seem to be much intermixed ; for, according to 
Humboldt, most of them are included within narrow bounds, 
quite different ones being met with every 200 miles. That the 
districts of the palm are small, and distinct from each other, 
(distributio speciebus disjunctis), is obvious from various con- 
siderations. Thus, no palm of the Old World is found in the 
New, with the exception of Cocos nucifera and Elais guineensis, 
which have probably been transplanted thither. Asia and the 
west of Africa have also no other in common than Borassus fia- 
belliformis , which, perhaps, in the latter place is not native. The 
palms of New Holland are peculiar to that country ; and those 
growing wild in the islands of Bourbon and France do not oc- 
cur elsewhere. Phoenix dactylifera appears to be at home only 
in the east of Asia, and in the north and interior of Africa. 
Cucifera thebaica (Hyphsene crinita), has hitherto been found 
only in Upper Egypt and Arabia. Chameerops humilis only in 
the south of Europe and north of Africa ; and the palms of 
North America are also peculiar species. Those most widely 
distributed are Cocos nucifera , which extends over all the con- 
tinents and islands of the Torrid Zone. Phoenix dactylifera , 
whose district includes a great part of Africa and Asia, together 
with a part of Europe, in a cultivated state ; and Raphia pedun- 
culata , which, according to Palisot and Beauvois, occurs on the 
west coast of Africa, as well as in Madagascar. The districts of 
the species are also, in the rule, small and isolated. Of twenty- 
two American genera, only seven are found elsewhere, ( Areca , 
Caryota , Cocos , Corypha , Elate , Elais , Chamcerops ) ; and, on 
the other hand, the genera Calamus , Sagus (Raphia), Nipa, 
Phoenix , Manicaria , Lodoicia , Licuala , Borassus , Hyphane 
(Cucifera), Latania , only appear in the Old World. Of the three 
known genera of New Holland, two, Seceforthia and Levistonia, 
are peculiar to it. 
The true home of the palms is indisputably the Torrid Zone. 
Of the 110 species described, only twelve are found beyond it, 
