236 Scientific Intelligence. 



are those of the volume, as ought always to be the case, for con- 

 venience and uniformity of reference. 



Dr. Engelmann deserves high praise and many thanks for taking 

 in hand, one after the other, our difficult botanical subjects, con- 

 centrating his attention upon them for a while, elucidating them to 

 the full extent of his opportunity, and leaving them in such a 

 state that they can be easily understood, or readily followed up 

 as occasion serves, by ordinary observers and collectors. His 

 latest essay of this sort was upon Yucca. He passes from that 

 to the analogous American genus. Agave, the " American Aloe," 

 first distinguished from the old-world Aloe genus by Linnaeus, 

 who gave them the present name, Agave, " because that word in- 

 dicates something grand and admirable." The headquarters of 

 the genus are in Mexico, but a considerable number inhabit our 

 southwestern borders, and one reaches well into the northern 

 States, There are " perhaps 100 species," — possibly a high esti- 



barium, while in cultivation they seldom blossom. The century 

 plant, A. Americana, may sometimes in our cool regions literally 

 answer to its popular name : semi-centennial specimens at least 

 are not uncommmi. 



Dr. Engelmann first devotes a few important pages to the gen- 

 eral structure and conformation of the trunk, foliage, inflorescence 

 and fructification in the genus, and passes to a systematic arrange- 

 of the N. American species as now known 



ment and descnpti 

 to him, and of a fe^ 



! light. They fall into three groups. 1. Singvliflorm, 

 with flowers in a simple spike, a single one to each bract. Our 

 northern Agave Virginica is the familiar representative : there 

 are also ^4. maculosa of Texas, and A. variegata from just over 

 the border, both in cultivation. 2. Geminiflorce, with a denser 

 spike, a pair of flowers to each bract. Our species are arranged 

 by obvious characters of the margin of the leaves, viz : with 

 tnentose mar- 

 dth aculeate- 

 toothed margins, A. hetearcantha, Zucc. (which is Torrey's A. 

 LechtiquUki), and A. Utaheusis, Engelm. 3. Paniculatm, the typ- 

 ical Agaves or Century-plants, with paniculate inflorescence. There 

 is a division with tube of the perianth much shorter than its lobes. 

 Under this A. Newlerryi, n. sp., is marked by the insertion of the 

 stamens on the base of the tube. The others, with stamens borne 

 in the throat, are A. deserti, n. sp., A. Parryi, n. sp. (doubtfiiUy 

 regarded by Dr. Torrey as a variety, latifolia, of A. Americana), 

 and A. Antillarum Desc, with orange-yellow flowers, now eluci- 

 dated from materials brought from iSan Domingo by Parry and 

 Wright in 1871. The division with tube of the perianth shorter 

 than its lobes, and bearing the stamens about its middle, contains 

 a very striking species, A. Shawii, from the southwestern corner 

 of California, which, having broad and deep-green leaves with a 



