199 NOTICES OF BOOKS. 
species remarked as yet, and it is shown that they are explicable by the 
theory proposed." (Introduction, page 16.) 
CaAcTEX i» Homro DYCKENSI cultæ Anno 1849, secundum Tribus et 
Genera digesta, additis adnotationibus botanicis characteribusque spe- 
cierum in enumeratione diagnostica Cactearum Doct. Pfeifferi non 
descriptarum, a PPE. Jos. pe Satm-Dyck. Bonne, 1850. 8vo. 
Joseph, Prince de Salm-Dyck, has long been known as a distinguished 
author on, and cultivator of, succulent plants, and his work on the Aloes 
and the genus Mesembryanthemum, with excellent figures, does him very 
great credit, and is indispensable to those who make those plants an object 
of study : and we heartily wish the illustrious author would favour the 
world with a similar publication on the Cacfez, which, more than any 
other plants, require the aid of the pencil to render the specific dis- 
tinctions intelligible. But we must not show ourselves ungrateful for the 
present work, which, though not so expressed in the title, is a second and 
very enlarged and improved edition of a * Catalogue ° published in 1844 
by the same author. In order, too, that this may serve as a supplement 
to Dr. Pfeiffer’s well-known ‘Enumeratio Diagnostica Cactearum 
hucusque cognitarum,’ Berolinis, 1837, full specific characters are 
given of all the species known since that period: so that the two 
works embrace all that is known of this extensive and remarkable 
family of plants. A ‘ Tabula Synoptica’ gives seven tribes and twenty 
genera, as follows :—Tribe I. Metocactex: Gen. 1. Anhalonium, 3 
species; 2. Pelecyphora, 1 sp.; 3. Mamillaria, 157 sp. ; 4. Melocactus, 
= 9sp. Tribe IT. ECHINOCACTEÆ : 5. Discocactus, 2 sp. ; 6. Malaco- 
 earpus, 6 sp. ; T. Echinocactus, 99 sp. Tribe III. CzREAsTREJZ : 8. Leuch- 
tenbergia, 1 sp. ; 9. Echinopsis, 19 sp. ; 10. Pilocereus, 7 sp. ; 11. Cereus, 
14lsp. Tribe IV. PuyrtocaAcTEE: 12. Phyllocactus, 8 sp. ; 13. 
Epiphyllum, 3 sp. ; 14. Disisocactus, 1 sp. Tribe V. RurPSALIDEE: 
15. Rhipsalis, 19 sp.; 16. Pfeiffera, lsp.; 17. Lepismium, 2 sp. 
Tribe VI. OruNTIEX: 18. Nopalea, 3 sp.; 19. Opuntia, 8 sp. Tribe 
VII. PrErREsCIE E: 20. Peirescia, 8 sp. In all, 578 species; a very 
large collection to be in the possession of one cultivator. In every 
ease full characters are given of the tribes and genera. 
