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. 

 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 (Fig. 80). 



FIG. 78. An orchid with aerial roots. 



