1816.) .Humboldi’s, Bc. Plants of South America. S77 
Torrid | Tempe-| Frigid 
Zone. rate Zone. 
Mean Zone. Mean 
Temp. Mean | Temp. 
805°, | Temp. |32°—30° 
50°—57° 
Agame cellulose.. 1:5 [1:2 |l: 1 
Filices’. 20..2.... 1: 60 jl: 25 |Ger.'34. Fraince 1, 
Monocotyledones. |]: 6 {1:4 |1: 3 
Cyperoidee ...... |1: 60 |I: 30 1: 9 
Graminee ...... jl: 15 jl: 12 j1:.10 
Juncee ........ j1: 400 jl: 90 j1:-25 IN. Am. =. Fr. 4. 
PeenprCME Yee i dies: lt: 4 
families ; 
Adimatse HOR. 6.5: 1: 40 |): 25.)/1: 70 JN. Amighoo Fr, 2. 
Ericinee — and 7 1 se : 
Rhododeridra. . ¢ [: 130 jl: 1001: 25 IN. Am. 3. Fr. =1,. 
Compositel S......{1: 6 4 8..jL: 13 
Rubiacez........ 1: 291k: 60 |1: 80 |Fr. .... Ger. 1. 
Umbellifere ..... {1 : 2000/1: 30 |L: 60 IN. Am. 2. Fr. 4. 
Crucifere ....,.. |1: 300U)1: 18 |]: 24 |N. Am. =. Fr, sty 
Malvacée........ jl: 50 |i: 200) O ‘ors «Fr. 
is: Ger. 5. 
Leguminose ..... rm TZ iTs PSs Bs 143 Ids 
Euphorbiacee .... |1: 35 |1: 80 |L: 50 
Améntacee ex- ‘ 
clusis Ghisane $ 1: 45 jl: 20 
The number of lofty trees in North America is much greater 
than in Europe. In North America there are 137 species of trees, 
whose trunks exceed the height of 40 feet, while in Europe there 
are scarcely 45 species. 
The plants of the torrid zone, as had been already observed by 
Mr. Brown, extend further through the southern temperate zone 
than through the northern. ‘his is to be ascribed to the greater 
influence of the ocean in the southern hemisphere, in moderating 
the rigour of winter. 
No firs are to be found on the mountains of South America be- 
tween the tropics, though they are very abundant in North America. 
In the temperate zones we frequently find the same species of 
plants growing together in clusters, as is the case with erica vulgaris, 
polygonum aviculare, pinus sylvestris, &c.; but such associations 
of plants very seldom occur in the torrid zone, where the woods 
consist of a great variety of trees nearly equably mixed. 
Several species of plants, though not many in number, are com- 
mon to the north temperate zones both of the old and new con- 
Vor. VII, N°V. 2B 
