1898 } REGENERATION AS EXHIBITED BY MOSSES 205 
cultures was due to the medium of growth, either upon flower- 
pot pieces or in water. Cultures, which from the beginning were 
made upon earth, showed essentially the same manner of growth, 
except that the side branches were robust instead of slender, of 
equal diameter instead of tapering, and were distinctly positively 
heliotropic. It was only very rarely that a protonemal branch 
was found penetrating the soil and becoming rhizoidal. The 
same result was obtained with protonemata, which were grown 
either in water or upon flowerpot pieces and then placed upon 
the soil, the further growth still being without rhizoid develop- 
ment. Luxuriantly growing protonemata from the stem of 
Funaria were half covered with earth without any appearance of 
thizoids. Schimper? grew Funaria protonema from the spores 
which did not show any rhizoid production. 
Vv. SUMMARY: 
Considering the various species of moss plants used in the 
foregoing experiments, there are, notwithstanding the variety of 
results, many striking similarities in the manner of regeneration, 
a brief summary of which will be brought together in the follow- 
ing conclusions: 
1. The majority of moss leaves used showed a. remarkable 
power of regeneration, producing either rhizoids or protonemata, 
with the later appearance of new leafy shoots. The rhizoid or 
protonema production was carried out in both light and dark- 
ness, 
2. The point of origin of the new growth from the leaf in 
some cases depended upon contact and illumination, and was 
independent of gravity (Mnium). In other cases the protonema 
had a definite origin which was independent of external factors, 
and depended solely on the leaf structure: from the ventral side 
of the leaf as in Atrichum, Polytrichum, and Phascum; or from 
marginal cells and thus independent of contact, gravity, illumi- 
nation, or position of the leaf, 
* Rech. anat. et morph. sur les mousses, p/ate 7. 1848. 
