2520 Journal of Applied Microscopy 



Sporophyte. 



16. Carefully pick out a young light-colored sporophyte inclosed in the peri- 

 gynium, an older one which appears green, and a nearly mature, yellow-colored 

 one from the under side of the archegoniophore, mount in water and draw under 

 low power, showing the capsule (sporangium), stalk, and foot. Describe. 



IT. Under high power draw sporocytes hanging together in chains and 

 spore tetrads from crushed capsules, also some mature spores. Draw one of the 

 elaters. What is their function ? 



18, Make a diagram in the notes showing the life cycle of Marchantia. 

 See Fig. 8. 



19. Ecological note. Describe how the air passages and the character of 

 the nonsexual spores show that Marchantia is adapted to an aerial habitat. 



XLVI. Appendix to Marchantia. 



(a) Conocephalus aviici/s (L.) Dum. Family, Marchantiaces. 



1. Study the thallus of Conocephalus and compare in general with Mar- 

 chantia. Draw. 



2. Under dissecting microscope, draw part of the surface showing the are- 

 olae with air passages. How do they compare in size with those of Marchantia ? 



3. Under low power, without cover-glass, draw an areola showing the crater- 

 like air passage. Does Conocephalus have any brood-bud cups ? 



(b) Lull Ilia ria cniciata (L.) Dum. Family, Marchantiaceai. 



1. Study the thallus of Lunularia and compare with Marchantia and Cono- 

 cephalus. Notice especially the numerous semilunar brood-bud cups. 



2. Draw a plant under the dissecting microscope, showing several cups. 



3. Under low power draw several areolae. How many methods of vegeta- 

 tive propagation has Lunularia ? Is there much need for sexual and nonsexual 

 spore reproduction ? 



XLVII. Porella platip/iyllal.. (Bellincinia). 



Class, Hepaticae. Order, Jungermanniales. Family, Jungermanniaceae. 

 This rather large, scaly liverwort is very abundant on the bark of trees. It 

 may be kept for a long time in good condition in a paper box. 



Gametophyte. 



1. Moisten a branch of the frond in water and sketch from the upper or 

 dorsal side under the dissecting microscope, showing the arrangement of the 

 lateral scales. 



2. Pick off some scales, being careful so as not to tear off the small, lower, 

 ligulate lobe which may be seen under the large upper lobe of the scale. Draw 

 under low power, showing both lobes of the scale. How many cells in thick- 

 ness is the scale ? Is there any midrib ? Why is this scale not homologous 

 with the leaf of a fern or one of the higher plants ? The scales are partly ana- 

 logous to leaves. 



3. Draw a few cells under high power. Of what advantage are the thick 

 walls ? 



