ADAPTATIONS TO OTHER PLANTS. 331 



size, or ionn adhesive disks by means of which they cling to 

 rough surfaces. These lateral organs are forms either of 

 leaves or lateral shoots, and are known as tendrils (figs. 107, 

 156). (For their form see ^[ 115, 158; for their action, 

 ^| 266, 293.) 



451. 2. Clambering plants are those which form lateral 

 organs not sensitive to contact, and by means of them sup- 

 port themselves on adjacent plants. Recurved leaves, shoots, 

 and prickles (fig. 115) may serve these purposes. 



452. 3. Twining plants are those which have adapted 

 their shoots to winding about a support of suitable size. (See 

 1 291.) 



453. 4. Root climbers have adapted their aerial roots to 

 attaching the plant to rough surfaces. (See ^[ 90.) All of 

 these organs are structures belonging to the sporophyte, and, 

 therefore, are found only in fernworts and seed plants. 



454. 5. Epiphytes. This name is rather loosely applied 

 to those plants which are attached to others for mechanical 

 support, and do not derive food from them. All kinds of 

 plants have representatives in this group. Algae, diatoms, 

 and other small water plants attach themselves to other alga? 

 and the higher water plants. Lichens, liverworts, mosses, 

 ferns, orchids, bromelias, etc., are abundant upon trees. 

 Epiphytes are attached by hair-like rhizoids, or by hold-fasts, 

 which apply themselves to the roughnesses or even penetrate 

 the outer dead parts, but do not absorb from the living tis- 

 sues of the supporting plant either water or food materials. 

 The water supply is provided for (i) by adaptations for ab- 

 sorbing rain or dew, mists, or even dampness, instantly, either 

 by the surface, as inalgae, mosses, and lichens, or by means of 

 hairs, as in the Spanish moss and other seed plants; (2) by 

 adaptations to catch the water in living or dead leaves and 

 hold it, either by capillarity or as a vessel, long after pre- 

 cipitation has ceased. Many of the simpler epiphytes are 



