198 REVIEWS. 



quently and regularly visited by " white moths, which, usually 

 in pairs, disported in the open flowers at dusk, and were found 

 quietly ensconced in them when closed in the day-time." 

 Professor Riley of St. Louis, the distinguished entomologist, 

 was at this point associated with Dr. Engelmann in the inves- 

 tigation. The result has been given to the scientific world in 

 his interesting memoir on Pronuha yuccasella, first read at 

 the Dubuque meeting of the American Association for the 

 Advancement of Science, in August, 1872, and now also pub- 

 lished, as a sequel to Dr. Engelmann's monograph, in the 

 " Transactions of the St. Louis Academy." 



"The rootstock of all the Yuccas is, under the name of 

 ' Amole,' an important article in a Mexican household, being 

 everywhere used as a substitute for soap, as it is replete with 

 mucilaginous and saponaceous matter, probably a substance 

 analogous to the saponine of the Saponaria root. It is curious 

 to learn that the negroes of the coast of South Carolina 

 repeatedly destroyed Dr. Mellichamp's carefully observed 

 clumps of Yuccas, in order to obtain the saponaceous root- 

 stock." In Colorado Territory we found that Yucca angusti- 

 foVia is as generally called " Soap-plant " as is the Chloro- 

 oalum in California. 



While the nature of the fruit, whether capsular or baccate, 

 is a tribal character in LUiacece generally, Yucca has both 

 kinds ; and Dr. Engelmann turns this character, with accom- 

 panying differences in seeds, to good account in the systematic 

 arrangement of the species. The common " Spanish bayonet," 

 Y. aloifolia of the Southern States, and some related Texan 

 and Mexican species, represent the pulpy - fruited section ; 

 Y. brevifolia, which ranges across the Arizonian border of 

 the United States, has a spongy indehiscent pod, probably at 

 first more or less dnq)aceous ; while the Bear-Grass, Y.Jila- 

 mentosa, and its allies bear a dry capsule. It may here be 

 recorded that the name Y. canaUcuhita of Hooker must re- 

 place that of Y. Trecvliana of Carriere, the latter being a 

 name published without characters, in 1858, the former de- 

 scribed and figured in 18G0, in the " Botanical Magazine." 

 The prince of Yuccas must be Yucca baccata, which, in its 



