l8 TRANS. ST. LOUIS ACAD. SCIENCE. 



course of a century (for most of our cultivated Yuccas have been 

 thus long in the hands of nurserymen), at last impress the obser- 

 ver with the dignity of specific characters. But the botanist finds 

 it necessary to fall back on the organs of inflorescence and fructi- 

 fication as the only safe guide in such difficulties ; here, however, 

 the cultivated Yuccas leave us in the dark. They yield us flowers, 

 to be sure, but we find the flowers so very similar in many species, 

 and again so dissimilar in different forms of the same species, that 

 evidently but little light can be obtained from their study. And 

 the fruits ? Unfortunately the Yuccas scarcely ever have borne 

 fruit in European gardens. The difficulties are increased by the 

 fact, that, as will be shown below, in their native homes these 

 plants vary remarkably in the structure and the form of even their 

 more important organs ; and before fuller examination of native 

 forms can be had, we must remain in considerable doubt as to the 

 limits of species. 



My attention was drawn to this genus, when, since 1842, Mr. 

 F. Lindheimer sent several then undescribed species from Texas, 

 and Dr. A. Wislizenus, and after him Dr. J. Gregg and Mr. A. 

 Fendler, others from New Mexico and Northern Mexico. A few 

 years later the botanists of the Mexican Boundary Commission and 

 of the Pacific Railroad Exploring Expeditions added to the stock of 

 our knowledge, and within the last decade the explorers of the 

 botany of California and of Arizona filled up some further gaps. 

 Within the last two years an unpretending physician of South 

 Carolina, Dr. J. H Mellichamp, who does not even claim to be a 

 botanist, but is imbued with arduous zeal and keen sagacity, and 

 who lives right among the Yuccas, has wonderfully improved his 

 opportunities, and has very greatly aided me in my investigations 

 by specimens as well as by his observations. I may add here that 

 also on other families of plants of his rich State, already so long 

 and well known through the labors of a Walter and an Elliott, 

 have his researches shed new light, as will appear in future pages 

 of these Transactions. 



Having thus been interested in the Yuccas for many years, I 

 ever had an eye on these plants, and in my travels in Europe 

 I neglected no opportunity to study them in the herbaria as 

 as well as in the gardens. There I was first struck with the " fact" 

 that " Yuccas do not bear fruit." To be sure, I had seen the fruits 

 in the Texan and New Mexican collections, and had observed the 



