tend 
ws [300 J 
tation consists of dense forests of leafy evergreen trees, palms, id vi 
erns, among which are intermingled epiphytal herbs and rigid grasses : 
there are no rich verdant meadows, such as form the chief beauty of our 
northern climate; and the lower orders of vegetation, such as mosses, fungi, 
and conferv = are very rare: myrtacee, ———— be: Sse 
e 
fleshy-rooted species; mosses clothe the trunks of aged trees; decayed vege- 
tables are covered with parasitical fungi; and the waters abound with con- 
Approaching the poles, trees wholly disappear; dicotyledonous 
fervee. Ap 
plants of all kinds become comparatively rare; sand grasses and crypto- 
~ gamic plants constitute the chief yaad of vegetation. To what cause, 
- 
ae 
‘ins ‘when etek ts ere bn to gin a Mal island, 
: shat to which they must het been often exposed: in the summer st in 
. their own climate... Assu ing, however; for the present; that ‘temperature 
ds the most efficient cause wal variety in sr distribution of plants, the first 
‘point. to consider is, how. far ‘temperature and. latitude are uniformly the 
same. in either hemisphere. This has been discussed, with his habitual 
skill, weg Humbold Anion whose observations L. must ‘avail myself in nearly 
all that I can sa n the subject. According to this choot the 'geo- 
graphical parallels a latitude do not indicate corresponding » 
either in the old and new world, or in the — om and: southern sega 
spheres. In the new wend; the dempeentoneis slee 
' ‘spobdig Entitndes of the northern ay ti but the winters milder. On 
this account, Humboldt coneludes that “the lines of equal mean annual 
“heat, which may be called isothermal, are not parallel with the. equator, but 
‘intersect the geographical parallels at a variable angle.” 
The following: t table shows the difference in the mean. annual heat of the 
sane latitudes in the old and new worlds: 
