P R EFA C E 



The accompanying paper, by Dr. J. N. Rose, is a continuation of 

 his Studies of Mexican and Central American Plants. It contains 

 a brief account of his seventh journey to Mexico. Most of the plants 

 discussed are new or recently described species which Doctor Rose 

 discovered in the field or while studying various groups of Mexican 

 plants. Some twenty-four new species of Crassulaceae are here 

 described. This is a remarkable addition to our knowledge of this 

 group, for the family had been extensively studied during several 

 years prior to 1905, when the North American species were mono- 

 graphed. Some of the present new species are of horticultural interest. 

 Echeveria crenulata, E. Jtolwayi, and E. gloriosa are somewhat similar 

 to the well-known E. metallica of our greenhouses. To Urbinia, a 

 recent segregate from Echeveria, two more species are added. One 

 of these, Urbinia purpusii, is a curious plant suggesting in habit and 

 foliage the south African genus Haworthia. The plant is worthy of a 

 place in every good succulent collection. In cultivation it has shown 

 no tendency to produce suckers and perhaps its propagation can be 

 accomplished only by seed. 



Frederick V. Coville, 

 Curator of the United States National Herbarium. 



in 



