314 FOUNDATIONS OF 
Fic. 220. — The Duckweed, a Floating 
Aquatic Plant. 
BOTANY 
(Sect. 368), we must 
consider that xero- 
phytes are highly spe- 
cialized and modified 
forms adapted to ex- 
tremely trying condi- 
tions of life. A typical 
xerophyte is one which 
can live in a very dry 
soil in a nearly rain- 
less region. The yucca 
in Plate VII and the 
melon-cactus (Fig. 49) 
are good examples of such plants. 
Less extremely xerophytic are plants 
like the date-palm (Fig. 54), which 
flourishes in the oases of the Sahara, 
where the soil is moist from the 
presence of springs, though rains are 
almost unknown, or the houseleeks 
and stonecrops found in many gar- 
dens, the so-called Spanish moss 
(Plate IV), and lichens (Figs. 198, 
199), all of which grow most rapidly 
in moist air, but cling to bare rocks 
and trunks of trees, from which they 
get no water. A xerophyte must 
be capable of storing water and tran- 
spirmg very slowly, like cactuses, 
aloes, stonecrops, and such fleshy plants 
1 Ficus religiosa. 
s 
BONN 
TN 
SN 
CXS LAX 
NS 
iin New 
36, 
KA 
*. 
a 
rt 
f 
CH 
xe 
Ss 
Ro 
NS 
WN 
DAF 
Gs 
t 
iy) 
=== U0 
Fic. 221.—Leaf of an 
East Indian Fig Tree, 
with a Slender Taper- 
ing Point to drain off 
Water. 
