274 APPENDIX. 



Three species of Agave and two of Yucca are recorded from Arizona ; and three each 

 of Agave, Nolina, and Yucca from California. About half of these species are common 

 to Mexico. In addition, there are at least half a dozen other Mexican species extending 

 to Texas and New Mexico, and perhaps as many as a dozen. One endemic species of 

 Agave and two Californian species of Nolina have been found in Lower California. As 

 to the northern limits of this type of plants in Central and western North America, 

 we only know that a few species reach Southern Colorado and Southern Utah. Enough 

 has been written, however, to prove that Mexico, and probably Northern Mexico, is 

 the centre of them, and that they thin out rapidly in every direction as we recede from 

 this centre. Plants of similar habit and aspect are found in the numerous species of 

 Aloe in South Africa, in Cordyline of Australasia, and Draccena of the Mascarene 

 Islands, &c* 



Liliacece. 



Under the "Agave and Yucca type," a portion of this order has already been 

 discussed, but the remaining genera demand a few words. These are thirteen in 

 number, and seven of them do not extend beyond America, and they number collectively 

 eighty-three species. It may here be observed that twelve out of a total of seventeen 

 genera have a north-western extension, though the number of species is only eleven. 

 Thirty of the eighty-three species belong to Smilax ; there are three Mexican mono- 

 typic, endemic genera, and a fourth is common to New Mexico and Arizona. Note- 

 worthy is the remarkably distinct and showy western genus Calochortus, of about thirty 

 species, six of which are subalpine in North and South Mexico, and endemic, and 

 twenty-one inhabit California, while a few are found in New Mexico and Arizona. The 

 genus ranges northward to British Colombia. Two genera, Zygadenus and Notho- 

 scordum, are common to Eastern Asia and America. 



Palmce. 



In consequence of the great difficulties attending the preparation and preservation of 

 specimens adequate for description and classification, palms are less known in detail, 

 perhaps, than any other class of plants ; indeed, we are assured by Sir Joseph Hooker 

 that he has hardly sufficient material of any one of the numerous palms of British India 

 to draw up a satisfactory description. Fortunately the successful cultivation of palms 

 in large houses has to some extent, small though it be, supplied the deficiencies of the 

 herbarium ; but the discoveries of the last ten years go to prove that the palm-world is 

 far from having been exhausted, even in the imperfect manner indicated. Palms, with 

 comparatively few exceptions, cover small areas, and are often exceedingly local, alike 

 in insular and continental regions. The cocoa-nut palm (Cocos nucifera) is the only 



* Since the above was in type Mr. S. Watson has sent us a description of Prochnyanthes, a proposed new 

 genus of the Agaveae, inhabiting Jalisco. 



