So 
2 A TEXT-BOOK OF BOTANY 
roots serving as tendrils. In the trumpet-creeper and 
poison-ivy these tendril-like roots cling to various supports, 
such as stone walls 
and tree trunks, 
by sending minute 
branches into the 
crevices. In such 
cases, however, the 
plant has also true 
soil roots. 
(4) Air roots. — 
Some plants have no 
soil connection at all. 
In the rainy tropics, 
where it is possible 
to obtain sufficient 
moisture from the 
air, there are many 
such plants, notable 
among which are the 
orchids, to be ob- 
served in almost 
any greenhouse. 
Fre. 78.—An orchid with aerial roots. Clinging to the 
trunks of trees, usu- 
ally imitated in the greenhouse by nests of sticks, they 
send out long roots which dangle in the moist air (Fig. 
78). Such plants are called epiphytes, the name indi- 
cating that they perch upon other plants and have no con- 
nection with the soil (Fig. 79). A very common epiphyte 
of our Southern States is the common long moss or black 
moss (although it is by no means a moss) that hangs in 
stringy masses from the branches of live-oaks and other 
trees (ig. 80). 
