38O APPENDIX. 



5. The two rows of large leaves on the upper flanks of the 

 stem. How do they overlap? Turn the shoot over and note a 

 third row of small underleaves in the center below ; also right 

 and left the lobes of the upper leaves. Determine the form of 

 the under and upper leaves. Make an enlarged paper pattern of 

 the latter showing how their ventral lobes are arranged. (Figs. 

 62, 63.) 



6. Demonstration. Mount a leaf and point out the uniformity 

 of cells and their abundant chloroplasts. 



7. Examine male plants* and observe the male branches: 

 short, abundant near the anterior end of main and lateral axes, 

 with crowded, closely overlapping leaves, the anterior ones often 

 pale. 



8. Cut off a male branch ; dissect leaves carefully and observe 

 in the axil of each leaf a spherical yellowish body on a slender 

 stalk, the spermary. ("|j 382, fig. 311, B.) 



9. Demonstration. Mount a mature but unbroken spermary 

 and show the single layer of cells forming a wall enclosing an 

 opaque mass of sperms. If fresh, the spermary may rupture on 

 being put into water and the sperms swim about rapidly in the 

 field of the microscope. 



10. Examine a female plant. On the under side observe very 

 short lateral branches, bearing a pear-shaped tumid sac, the 

 perianth. How is it constructed at the free end ? 



11. Examine old perianths ; observe partly projecting from 

 such the mature sporophyte, consisting of a brown spherical capsule 

 on a pale slender stalk {seta). (The capsule is often bursted ; if 

 so, determine into how many pieces {valves) it splits.) To what 

 is the stalk attached? {% 32, figs. 64, 65.) 



12. Examine successively younger female branches (to be 

 found toward the anterior end) and note various stages of devel- 

 opment of the sporophyte. Find a young sporophyte, differenti- 

 ated into stalk and capsule, but still enveloped by a thin mem- 

 brane, formed by the enlarged body of ovary and surmounted by 

 a brown bristle, the neck of the ovary. Determine what becomes 

 of this membrane {calyptra). 



13. Demonstration. Select the youngest female branch with 

 well grown perianth, cut a median longitudinal section, or dissect 

 away the perianth, mount, and show the group of several ovaries ; 

 some with canal cells in place, others with canal cells disorgan- 



* The sexual organs are borne on different plants. 



