382 APPENDIX. 



Holding one half with needle cut off the peristome close to cap- 

 sule. This allows the teeth to float away fron:i membrane. Turn 

 other half with convex side up, cover all pieces, and show the 

 peristome, endostome, and spores. 



Examine young sporophytes of this or other mosses. Observe 



14. The cylindrical form of the embryo sporophyte. 



15. The hooii covering its apex and carried up by it until the 

 developing capsule forces it off. (fl 401, fig. 338.) 



16. The //(/ which falls off to open capsule. 



17. Examine on young gametophytes the sex organs. Dissect 

 with needles the tufts of leaves at apex of stem '" and search for 

 {a) Transparent oval sacs, the empty sperfnaries ; and similar 

 opaque greenish or whitish ones, in which sperms are still en- 

 closed. (^ 384, fig. 311, B). {h) Flask-shaped bodies, with a long 

 neck and short stalk, the ovaries. These may always be found, 

 withered somewhat, at the tip of a stem where a young sporo- 

 phyte is developing. (T[ 391, fig. 331.) 



Numerous hairs, paraphyscs, of no known function, may be 

 found intermixed with the sex organs. 



19. Demonstration. With dissection as above, mount spermary 

 and ovary. Show {a) in spermary, the stalk, the wall, the sperm 

 cells ; (/') in ovary, the stalk, body, neck, canal, and egg. 



IV. PTERIDOPHYTES. 

 A. MAIDENHAIR FERN {Adiantum pedatum). 



I. The gametophyte. 



1. Observe its shape and size ; the notch at the growing point 

 (anterior end) ; the dying (posterior) end ; the thicker central 

 region, with thin wings. (^ 69.) 



2. On the under side, a cluster of rhizoids near the posterior 

 end. 



3. Compare this plant with the thallus of Marchaniia. 



4. Demonstration. Mount a gametophyte underside up, and 

 show {a) among the rhizoids the spherical spermaries ; {/>) nearer 

 the apex the chimney-like necks of the ovaries. 



If gametophytes with young sporophytes attached are available, 

 observe 



* In some species the malu organs form at the apex of the axis disk-like clusters, sur- 

 rounded by leaves, the whole reminding one \n form of a miniatuie sunflower-head, 

 while the female organs occur in smaller numbers (3-6) in the bud-like clusters of leaves 

 at the apex of other steins. 



