302 COLLEGE BOTANY 



The Lycopodiales or club mosses have the general appearance 

 of large mosses and are sometimes called gronnd pines. The life 

 history is very similar to that of the ferns. 



Uses of Pteridophytes.— This great group of plantsi is of 

 very little economic value except for ornamental purposes. How- 

 ever, the collecting and growing of ferns involves very large in- 

 vestments of capital. 



LABORATORY EXERCISES. . 



Exercise 1. Use any typical fern that may .be convenient. 



8porophyte. Examine surface and cross-sections of the leaf and com- 

 pare with the leaf of the higher or flowering plants. Note the sori on 

 the lower surface of the leaf. Xote the indusium if present. 



Remove a sorus and examine under the microscope. Note the struc- 

 ture of the sporangia. Also note the opening of the sporangia and the 

 scattering of the spores. 



Gametophyte. Examine the prothallus and compare with M. poly- 

 morpha. Note its form, thickness, rhizoids, etc. 



Examine a prothallus from which a young Sporophyte is just starting. 



Exercise 2. hycopodium lucidulum Mx., or oth«r species of club moss. 

 Note the appearance and character of the entire plant. Note the location 

 of the sporophylls and the spores. If Hrlaginella or Tsoetes is available, 

 note the two kinds of spores. 



Exercise 3. Equisetum arvense L., or horsetail. (Collections of this 

 material should be made at different times.) Examine the entire plant 

 and note the underground stem, the sterile and the fertile shoots. 



