Notice of a Flora of North America. 279 
posite, which is justly termed by De Candolle, “Ordo omninmn 
naturalissimus et vastissimus et idéo difficillimus,” and which, 
Drs. Torrey and Gray, following in that respect the arrangement 
of Lessing, divide into three sub-orders, comprising, together, 
eight tribes, which are of very unequal importance in respect to 
the number of genera which they embrace. The first tribe, 
Vernoniacee, is very small, being limited to six genera, of which 
Vernonia is the most important; and we notice a new species 
from: Florida. The second tribe, Eupatoriacee, comprises twen- 
ty-one genera; none of much importance, (within the geograph- 
ical limits of this work,) except Liatris and Eupatorium. Of 
the former genus, a new species is introduced from Georgia, and 
three species, as heretofore characterized by botanists, are now 
temoved to the genus Carphephorus, established by Cassini on 
the Liatris squamosa, Nutt., our authors observing, that “on ex- 
oe the athied: species of  Reidiris,: we find that all those with 
eads ¢ eym 
ida, and a well known cipher is species of Ageratum is reco 
for the first time, as a native of mE ed S « Dhe:#ithors 
temark, that these two genera are not wscenly aes “We 
further notice, in this tribe, a new species of ' . 
from the interior of Texas. We now come to the: sieadsaliehie 
ttibe Asteroidee, of which the first subdivision (Huasteree) oc- 
cupies nearly one half of the present number. This section is 
confined to the several genera, and sub-genera, comprehended 
under the popular name of Asters, which have so long been the 
terror and stumbling-block ‘of American botanists. It appears, 
from an introductory note, appended to'the genus Aster, that Drs. 
Torrey and Gray have enjoyed great advantages in the study of 
this most difficult tribe, being “ greatly indebted to several bota- 
Rists and public institutions in this country, for the use of their 
entire collections of American Asters ; and we would especially 
tender our acknowledgments to Sir Wm. Hooker, who, by most 
liberally entrusting to our care his vast materials in thisand — 
allied genera, has afforded the most important assistance.” * * * 
“The original genus Aster, of Tournefort and Linneus, has sue 
-subdivided by modern botanists, and, according to their 
arrangement, is made to consist of some eight of ten genera. 
