[3003 “sale 68 
*The plants of rocks ; these sd by insencible heikasiens to those of 
alls rocky and stony places, and even of gravel ; aud the latter soil, as its 
fragments diminish in size, conduet us by degrees to the following class. 
Rock plants offer some remarkable Not a depending upon the na- 
ture of Bas € roc 
8. slants of ie or of very burren soils ; in the classification of 
which saul difficulty is experienced : thus, Hanis of the sand of hie sea 
ore are csbinuaded. wan saline plants; those barren soil, wi 
species of cOnPontse: land ; and those of coarse sand are not diferent aan 
those of gra 
“ * ants “of sierile places, that are very compact, as stiff we oad soil, or 
such as have their sp sch by drought or heat, or thos which 
are trodden hard by man or animals. ead is an heterogeneous pei and 
contains plants of very sree elinis rac 
lants which follow man. ieee 4 are few in number, and more 
fixed in their station, either in consequence ie nitrous salts being necessary 
to their existence ; or because, perhaps, azotized matter is required for their 
_ nutriment. 
V1. Forest Sel among which are to be distinguished, Istly, the trees 
that form the forest; and, 2dly, the herbs which grow beneath their shade. 
e latter are to th Sapereied into two kinds; those, Ist, which can support 
a considerable degree of shade during all the ° year, whic h are found in ever- 
green woods ;t or such, 2d, as require light in the winter, like those which ‘ 
ere found among deciduous trees. 
12. Bushes and hedge plants. he shrubs which compose this nae 
differ from the plants of the forest in their smaller size, and in- 
ness of their leaves ; the at neha kinds that grow among Pd are ordi- 
narily climbing plants re 
13. Sublerranean plants, which live either in dark caverns, as the-bys- 
sus, or within the bosom of the earth, as the truffle. These can dispense 
altogether with light, and several cannot even endure it. Plants that grow 
in eee hollows of old trees have great analogy with those of caverns, 
Jountain _— as subdivisions of which all the other stations may 
be pia: We generally class a amipng mountain plants such as, in Enro ope,” 
are not found lower than 500 yards ; but this is ate: an arbitrary limit. 
‘The most important division is between those which grow on 
the summit of which is covered with eae snow, 
tains whieh ipse aye crest of snow in the summer. In the 
€ supply of 
e evidently 
15. Parasitical plants ; that is to say, such as are either destitute of 
the power of pumping up their nourishment from the soil, or of elaborating 
* The ae tahaya, ¢ or strawberry pear of Yucaian,a most delicious fruit 
eal pin eapple, is produced by a creeping trianguiar species of cae 
pea 
aces of the interior, and the ¥ very 
rive m the most dry and barren soils. 
a 
agaves, f Yucatan, flour Jy both o € very stony surfa 
a ast e med’ Sak aloes willt 
er-shaded “aap of ever-green woods, embra: ‘3 
ips vegeiabis of the slg go e.g. the eelebraied Diccuse ri te i pSestatued er 
ine, 
: the ¢ 35 and 
ieee seen 
S; 
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