SEEDLESS PLANTS 



two moistened bits of glass and hold it up to the light, keep- 

 ing the upper surface toward you ; what is its appearance ? 

 Observe a tiny dot near the center of the rhomboidal 

 areas into which the epidermis is divided and compare it 

 with your drawings of stomata (Sec. 16). What should 

 you judge that these dots are? 



372. Rhizoids. Wash the dirt from the under side of a 

 thallus and examine with a lens ; how does it differ from 

 the upper surface ? Observe the numerous rootlike hairs, 

 or rhizoids. What is their color ? Where do they spring 

 from ? These are not true roots, but hairs that have taken 

 upon themselves the function of absorption, and do not 

 imply any actual differentiation of tissues. 



Plant a growing thallus branch in moist earth so that 

 the upper side will lie next the soil and watch for a week 

 or two, noting what changes take place. What would you 

 infer from this as to the cause 

 of the difference between the 

 two surfaces ? Would rhizoids 

 be of any use on the upper side ? 

 Stomata on the under side ? 



373. Gemmae. Look along 

 the upper surface of some of 

 your specimens for little saucer- 

 shaped (in Lunularia, crescent- 

 shaped) cupules or cavities. 

 Notice the border, whether it 



7 .-Lunularia, a common ^ tO thed F Cntire > and S6e if 

 livenvort : 504, portion of a thallus yOU Can tell what the CUpuleS 



Sos^'fertne^lant wiUi^fmUm^ conta i n - These little bodies, 



receptacles; 506, an enlarged sec- called gemma, are a kind of bud, 



tion of one of the fruiting recepta- 

 cles ; 507, portion of a sterile thallus 

 slightly enlarged, showing one of 



the crescent-shaped gemmae from j , , 1M i i r 



which the plant takes its name. and the tiger Illy do by means of 



bulblets. Sow some of the gem- 

 mae on moist sand, cover them with a tumbler to prevent 

 evaporation, and watch them develop the thalloid structure. 



by which the plant propagates 

 itself somewhat as the onion 



