122 MAIDEN-HAIR FERN. 



4. The absence of fibro-vascular bundles. 



5. The trichomes in the form of hairs of various 

 kinds. 



a. Shorter or longer pointed hairs on the surface 

 and margin." 



b. Short blunt hairs in like positions. 



c. Rhizoids. Note 



i. Their various sizes and lengths, 

 ii. The irregular shape. Draw. 



6. Roundish bodies of considerable size near and 

 among the rhizoids, the sexual organs. 



Examine with a high power, and notice the two sorts : 



a. Some bodies spherical and filled with smaller 

 cells, the antheridia. Observe 



i. The single layer of cells forming a wall la 



which incloses 



ii. A cluster of spherical cells, the sperm cells. 13 

 iii. If fresh material is being used, some mature 

 antheridia will probably have been ruptured 

 in mounting and the sperm cells with their 

 antherozoids have escaped. Note the movements 

 of the antherozoids after they have escaped 

 from the sperm cells. Kill them by treating 

 with iodine, watching them as they come 

 under its influence. Take note of the body of 

 the antherozoid, a spirally coiled filament to 

 which is usually attached an almost empty 



11 Sometimes wanting. 



12 Best seen in immature antheridia. All stages may usually be found 

 on the same prothallium. 



13 If the structure of the antheridia can not be made out easily here, 

 postpone the study till D, 8. a. is reached. 



