MR. J. G. BAKER ON ALOINE<E AND TUCCOIDE^!. 151 



Agaves, in the south wing of the large temperate house ; and I 

 have found it very useful in preparing this present synopsis. 



Of the Tuccas, three species were known long before the time 

 of Linnaeus. A large number of new forms from Mexico, Cali- 

 fornia, and the Western United States have been made known 

 during the last twenty years. Most of these have been intro- 

 duced into cultivation ; but many of them are only known in an 

 undeveloped flowerless condition. Mr. Wilson Saunders made a 

 speciality of the genus, and got together at Reigate a fine collec- 

 tion, of which the forms that flowered will be found figured in 

 the fifth volume of the ' Eefugium ' (tabs. 313 to 325). Dr. En- 

 gelmann's monograph, which appeared in the third volume of the 

 ' Transactions of the Academy of Science of St. Louis ' in 1873, is 

 a very valuable accession to our knowledge of the genus. The 

 flower is fertilized by a moth, and the fruit, which Dr. Engelmann 

 has shown to furnish excellent distinctive characters, is hardly 

 ever produced in cultivation, the plants being capable of being 

 preserved for an indefinite time by vegetative reproduction. The 

 same volume of the ' Transactions ' of the St. Louis Academy 

 contains a full account and figure by Mr. Riley of the fertilizing 

 moth (Pronuba yuccasella) and the manner in which its work is 

 performed. In the systematic portion of my synopsis references 

 will be found to the papers on the genus by Carriere, Lemaire , 

 Hemsley, Karl Koch, and myself, which have appeared in the 

 horticultural periodicals. 



Dasylirion and Beaucarnea, which resemble Yucca in general 

 habit, but have minute polygamo-dioicous flowers, belong en- 

 tirely to Mexico and the Southern "United States. Several spe- 

 cies are in cultivation ; but many others are imperfectly known ; 

 and both here and in Yucca there is ample scope for further 

 exploring work. Herreria, which is a climber with prickly stems, 

 belongs entirely to Extratropical South America and the plateau 

 of Central Brazil. 



The only striking deviation from typical Liliaceous structure 

 shown in this portion of the order is in the polygamo-dioicous 

 flowers of Dasylirion and Beaucarnea and the indebiscent one- 

 celled one-seeded capsule of the former genus. 



Of the 195 known Aloes, about 170 are natives of the Cape. 

 Of the 47 Yuccoideae, 44 belong to the northern and 8 to the 

 southern half of the American continent. 



