F. CaverS. 
164 
young shoot arising from a germinating gemma is formed in exactly 
the same manner as that proceeding from a germinating spore of 
the same species. In the majoritiy of the leafy forms, the 
germinating gemma, like the germinating spore, usually gives rise 
to a “germ-tube,” a slender filament at the distal end of which the 
young leafy shoot is developed. On the other hand, in Aneura, 
Radula, Frullania, and the Lejeuneae, the formation of a germ-tube 
is suppressed; the germinating spore or gemma of Aneura gives rise 
to a flattened ribbon-like outgrowth, the distal end of which is from 
the first occupied by the two-sided apical cell of the shoot, whilst in 
Frullania, Radula, and the Lejeuneae, the gemma exactly resembles 
the protonema arising from the spore, forming a discoid cell-mass, 
from the margin of which the leafy shoot takes its origin. 
As regards the influence of external conditions on the formation 
of adventive shoots from excised portions of the Liverwort-gameto- 
phyte, the writer has found that, both in the thalloid and the foliose 
forms investigated, regeneration takes place in darkness as well as 
in light, but that the shoots formed in the dark show only feeble 
growth. This was observed in Reboulia hemispherica, Preissia 
coiuinutata, Marchantia polymorpha, Lunularia cruciata, Fegatella 
couica, Pellia epiphylla, Lophocolea bidentata, and Scapania undulata ; 
a similar result was obtained by Heald 1 in the case of Lophocolea. 
Schostakowitsch was unable to obtain regeneration in cultures of 
severed leaves of various Jungermanniales which he kept in dark¬ 
ness, though Klebs- found that in Lophocolea the leaves produced 
new shoots from the marginal cells when placed in weak light, 
whilst spores grown under similar light-conditions produced germ- 
tubes but no leafy shoots. Schostakowitsch found that no regene¬ 
ration occurred in detached leaves which were cultivated in air 
deprived of C0 2 , and concluded from this negative result that light 
does not exert a specific influence on the regeneration-processes, 
which failed to take place in this case on account of the lack of 
plastic food-materials. 
Apospory. 
Apospory, or direct origin of the gametophyte from the 
vegetative tissue of the sporogonium without the intervention of the 
spore itself, has been observed to take place in a number of Mosses, 
when the sporogonium has been detached and cultivated in 
1 Heald, F. de F., Gametophytic Regeneration as exhibited by 
Mosses, etc. Inang.-Diss., Leipzig, 1897, p. 21. 
2 Klebs, G., Ueber den Einfluss des Liclites auf die Fortpflan- 
zuug der Gewiickse. Biol. Ceutralblatt, Baud. 13, 1893, 
p. 649. 
