229 
broad and deep the foundations of American botany. But Dr. Gray, 
his pupil, survives, with matured wisdom and erudition, and it is a 
subject of great congratulation that we find him, still in the vigor of 
his powers, resuming the task apparently so longsuspended. As the 
harvest is about ripe, we may hope that the gathering will take a 
comparatively short time. The whole work it is calculated will be 
contained in two volumes of about 1200 pages each. The first vol- 
ume will “cover the ground which was gone over in the work 
referred to (now wholly out of print as well as antiquated).’”’ The 
present issue, Part I. of Vol. II., begins where that stopped and com- 
prises the remainder of the Gamopetale. Part II. of Vol. II. will 
be devoted to the Apetale and Gymnospermae, “ and the final por- 
tion to the Monocotyledones and the Vascular Cryptogamia. 
“Compactness being essential, only the leading synomy and most 
important references are given, and these briefly.” The descrip- 
tions are in English, and the arrangement and typography admirable © 
for the purpose of investigation. The fuller synonomy and bibli- 
ography will be found in Mr. Watson’s Index, which is expected to 
proceed pari passu with this Flora. The territory covered is the 
United States and all the North American continent and islands 
northward, Greenland excluded. The order followed is that of 
Bentham and Hooker, whose Genera, as far as published, end with 
Plantaginaceae, as does the work before us. Dr. Gray, however, 
separates Lobeliaceae from Campanulaceae, and, on the other hand, 
comprises the Vaccineae and Monotropeae under Ericaceae, imme- 
diately after which he places Lennoaceae, (Torrey’s Ammobroma 
and its allies,) and not with B. & H. after Diapensiaceae. Dr. 
Engelmann supplies the genus Cuscuta. We find Solanum Fendleri, 
of New Mexico and south, now recognized as Solanum tuberosum, 
L., var. boreale, so that we can now say that the potato is a native 
of the United States. There are described in this Part of the Flora 
1663 species, belonging to 321 genera and 32 orders. The corres- 
ponding orders in Bentham & Hooker have about 1340 genera and 
18,800 species. This gives, for the World, an average of about 42 
genera for one of these orders, and 14 species for a genus ; for 
North America about 10} genera for an order, and 54 species for a 
genus. Thus we have about 24 per cent. of all the genera and 9 per 
cent of the species, showing a still greater preponderance of genera 
over species than in the case of the Polypetalae which we pointed 
out in the notice of Mr. Watson’s Index. Dr. C. W. Short, of Col- 
umbia College, in speaking of Dr. Torrey’s genial influence, once 
remarked that his greatest contribution to science was his pupil, Dr: 
Gray. New York botanists may well take pride in claiming these 
eminent men as compatriots. The publisher’s price for this part is 
$6. Ivison, Blakeman, Taylor & Co., New York. It may also be 
obtained from the Curator of Harvard University Herbarium, Cam- 
bridge. : 
fi Papers from the Transactions of the Academy of Science, St. 
Louis, Vol. III., No. 4, by Dr. George Engelmann: The Flowering 
of Agave Shawit. The phenomena presented by a fine specimen in 
Mr. Shaw’s greenhouse are here described and illustrated by this 
