260 APPENDIX. 



genus, is common to Mexico and Texas westward to California, the Himalayas, China, 

 and Japan. 



Laurinece. 

 Only thirty-six species, several of them imperfectly known, are recorded from within 

 our limits; and Grisebach describes only twenty-six in his 'Flora of the British West- 

 Indian Islands,' whereas the number in Brazil is about 320. In all probability, how- 

 ever, further explorations in Central America will yield a considerable addition to this 

 order. IMsea glaucescens, a very variable species, is perhaps the commonest in the 

 Mexican region, where it rises to an altitude of 8000 feet. TJmbelMaria californica is 

 the only member of the order inhabiting western North America ; and in the Atlantic 

 States there are seven species belonging to five genera. 



Euphorbiacece. 

 This order is seventh in numerical strength of species within our limits, and sixth in 

 the whole world. Our 368 species, of which 240 are endemic, are largely made up by 

 the widely-spread genera Euphorbia, Jatropha, Croton, and Acalypha; these four 

 contributing no fewer than 246. Altogether we have thirty-two genera, two of them 

 endemic, and sixteen extending beyond America. Pseudocroton is an endemic mono- 

 typic genus in Nicaragua, and Dalembertia is a small genus restricted to Mexico. The 

 genus Euphorbia presents a great variety, from the gorgeous E. pulcherrima down to 

 minute annual herbs. 



Cupuliferce. 



Taken in the broad sense, that is to include the Betulese and the Corylese, this order 

 comprises ten genera and about 400 species, generally dispersed in the northern 

 hemisphere, and extending to the mountains of tropical Asia and America. One 

 genus only, Fagus, reappears in the extratropical regions of South America, Australia, 

 and New Zealand, where it constitutes an important element of the forests. The 

 genera represented within the limits of this work are Alnus, Carpinus, Ostrya, and 

 Quercus ; yet, with the exception of the monotypic Ostryopsis of Eastern Asia, all the 

 genera are found in North America, where the aggregate of the species is higher than 

 it is either in Europe or Central Asia. Betula, Alnus, Carpinus, Ostrya, Corylus, 

 Quercus, Castanea, and Fagus occur in the South-eastern States of North America; 

 and Betula, Alnus, Corylus, Quercus, and Castanopsis in California. The absence of 

 Fagus in California and Mexico is noteworthy, especially as the genus is common in 

 the forests of Chili, commencing in about 33° S. lat. Quercus and Alnus extend to the 

 Andes ; the former numbering three South-American species and having its eastern limit 

 at Pamplona and its southern limit about Popayan ; the latter one variable species, which 

 is very common in the mountains from South Mexico to Chiriqui, Colombia, Peru, 



