OEOORAPHICAL SITUATION OF PLANTS. 
207 
DoM and graphic language, said,* " A practical botanist can 
usually at the first glance distinguish the plants of Africa, Asia, 
America, and the Alps ; but it is not easy to tell how he is able 
to do this. There is a certain character of sullenness, gloom, 
and obscurity in the plants of Africa ; something lofty and ele- 
vated in those of Asia ; sweet and smiling in those of Ameri- 
ca; while those of the Alps seem rigid and stinted." In in- 
vestigating the geographical situation of the vegetable kingdom 
we see the powerful effects of light and heat'. Feeble in the 
pola/r regions.^ vegetation acquires strength as we approach to- 
ward the equator., where the light of the sun is vivid, and its 
heat permanent and intense. At the termination of the land at 
the Arctic Ocean there is one long, cold night, and one day of 
warmth, in which vegetation is rapidly brought forw^ard ; plants 
in some cases germinate, blossom, perfect their seed, and die 
within six weeks. Within the limit of perpetual snow the arc- 
tic sailors have found large patches of the Palmella nivalli^ 
red snow (of the algae tribe), the simplest of all the vegetable 
race ; the plant consists but of one cell., containing a fluid. On 
the Alps and Pyrenees it is found reddening the surface of the 
snow, trom which it derives its support. A species of lichen 
(the G-yrophora) was found, and used for food by Sir John 
Franklin, within the arctic circle. After passing from the arc- 
tic circle to the borders of the temperate zone, we find a few 
species of plants, chiefly lichens^ mosses^ and ferns^ also a few 
.^hruhs and herries. Lapland is the only country wnthin this 
zone where any kind of grain can be raised. In those frozen 
climates plants are low and stinted which in other situations 
rise to a great hight. The heech and willow., the giants of those 
regions, rise but a few inches above the surface of the ground, 
while their stems lie hidden among the moss, as if wanting 
strength to penetrate the soil. 
319. Humboldt divided the temperate zone., with respect to 
productions, into three regions : the cold., the temperate., and 
warm I in the cold region grain may be raised to advantage, 
and herries grow in abundance. In the temperate region the 
wine-grape., grain., and fruits of many kinds are cultivated in 
their greatest perfection. The warm region produces olives., 
p'gs. oranges^ and lem.ons. The variety of plants in the torrid 
zone is very great ; trees are more numerous in proportion to 
other plants than in the temperate zones; the same tribes 
which are there slender and humble plants, here spread into 
lofty trees many of which are adorned with large and beauti- 
• * Primo intuitu distinguit saepius exercitatns botanicns plantas Africas, Asise, America, Alpium- 
|ne, sed non facile dicerit ipse ex qua nota. Nescis quae facies torva, sicca, obscuris Afris i quae 
luperba exaltata Asiaticii ; qu<e la;ta, glabra Americanis ; quae coarctata, indura Alpinis.' 
Plants of the frigid zone. — 319. Temiicrate zone — Torrid zone. 
