- 42 — 



trichum and Phascum; from marginal cells and thus inde- 

 pendent of contact, gravity, Illumination, or position of the leaf. 



3. The power of regeneration may be distintcly localized : 

 a. In special cells of the leaf base as in Barbula, Brachythe- 

 cium, and Funaria. b. In special cells of the ventral leaf 

 surface as in Atrichum and Poly trichum. In other cases the 

 power of regeneration was quite generally shared by all the 

 leaf cells as in Mnium, Bryum, and Phascum. 



4. The structures produced might be entirely rhizoid in 

 both light and dark as in Mnium , and occasipnally so in 

 Phascum. They were protonema in light and rhizoids in the 

 dark as in Bryum, Barbula, Brachythecium and Phascum, or 

 they were entirely protonema in both light and dark as in 

 Atrichum and Poly trichum. 



5. Buds were produced under ordinary conditions of 

 cultivation only in the light in the following : Mnium, Funaria, 

 Bryum, Barbula and Brachythecium. In both light und dark 

 by Atrichum and Poly trichum under ordinary conditions and 

 by Phascum when supplied with grape sugar. The pro- 

 duction of buds seemed to be in a measure dependent upon 

 the food supply. 



6. The regeneration was called forth in all cases by the 

 Separation of the leaf from the stem. The mere cutting of 

 the leaves while in connection with the stem did not call 

 forth the production of protonema or rhizoids. 



7. The majority of moss stems as well as the leaves 

 showed regeneration and that in two ways: a. By axillary 

 shoots. b. By protonema direct or by rhizoids which in the 

 light very soon gave rise to protonema branches. The stems 

 in two cases had the power of regeneration while this power 

 was not shared by the leaves (Fissidens and Ceratodon). 



8. The production of axillary shoots was not called forth 

 by defoliation of the stem, but was generally accelerated 

 thereby. In some cases the protonema production was called 

 forth by defoliation, in other cases only accelerated. 



9. The protonema production was quite general through- 

 out the entire extent of the stem. In some cases the pro- 



