GEOGRAPHICAL DISTRIBUTION OF PLANTS. 539 
prehended between 36° and 30° of latitude, will constitute the 
Southern region. 
The Northern region of America well deserves to be called the 
region of theStarworts and the Golden or Copper Birches (Solidago) ; 
those beautiful composites abound there with the genera Liatrus, 
Rudbeckia, and Gaillardia of the same family. The Cinotheras, 
Clarkias, Andromedas, and Kalmias, charming ornamental plants, 
well known in our flower gardens, likewise characterise this vege- 
table zone. Amongst the most abundant species, we may mention 
the numerous species of Pines, Firs, Larches, Thujas, Junipers ; no 
less than twenty-seven species of Willow, twenty-five others consist 
of Oaks, Beeches, Chestnuts, Wych Elms, and Hornbeams, Alders, 
Birches, Poplars, Ash, and Elms, with which are mingled the 
American Plane; the Liquidambars, the trunk and branches of 
which furnish juices used in medicine; the Tulip-tree,. with singu- 
larly truncate leaves and large, spreading, solitary, yellowish 
flowers; different species of Maples, Lime-trees, Robinias, and Wal- 
nut-trees. Together with these numerous and varied arborescent 
species, which attain considerable dimensions, grow the Myrica 
cerifera, which furnishes an abundant wax drawn from the fruit by 
boiling ; the Currant bush (/bes), with coloured and ornamental 
flowers in great varieties of red, yellow, and white; the elegant 
Andromeda, Azalea, Rhododendron and Meadow Sweet present 
themselves in endless varieties ; Sumacs, a species of which (Rhus 
toxicodendron), with greenish yellow flowers, contains a juice so acrid 
that contact with it produces blisters and erysipelas, and others a 
dangerous poison ; with Ceanothus, Hollies, and Blackberries. 
The Southern region is comprehended between 30° and 36°; 
its vegetation somewhat resembles that of the tropics, being a 
transition between the temperate and torrid zones. Walnuts, 
Wych Elms, Chestnuts, and-Oaks are found there, and alongside 
of them three specimens of Palms,—the Chamerops palmetto, the 
terminal buds of which form a delicious legume; some Yuccas, 
some Zamias among the Cycadew; some Passifloras, woody 
twining plants, such as Bignonia Sapindus, Cactuses, Laurels. 
Lastly, by the side of the Tulip-trees, Pavias and Robinias, grow 
magnificent Magnolias, of which this is the true domain, The 
vegetation of this region is thus remarkable in its variety. The 
