352 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
etiolated plants, and he goes so far as to suggest the name of 
naturally etiolated plants for the class. This term is not 
particularly appropriate from the standpoint of the nutrition 
theory, but if we consider etiolation as an adaptation in relation, 
to the search for light, it is suitable enough. 
One more case may be mentioned as illustrative of Godlewski's'- 
theory. Marchantia, one of the Liverworts, is a well-known 
cryptogamic plant which grows like a flat green plate on the' 
ground. Marchantia reproduces itself vegetatively by means of 
gemmcB, minute bodies which play the part of tubers. These 
gemmae absolutely refuse to germinate in darkness ; instead of 
exaggerating their growth in one direction, like the potato-shoot, 
they do not attempt the task of escaping into the light.* If it 
is remembered how slight must be the chance of escape from 
darkness, in the case of a minute plant growing flat on the 
surface of the soil, it will be allowed that the best chance of life 
lies in waiting ; the dry leaves, earth, or other debris which 
cover the gemma may, by some lucky accident, be removed, 
whereas the chance of freeing itself by growth is too small to 
make it worth while to attempt it. I do not lay great stress on 
this case because there is a lack of supporting evidence. Indeed 
in certain similar cases germination actually occurs in darkness. 
Thus the spores of some ferns, though not of all, produce a 
prothallus even in the absence of light. There are, however, 
similar instances of Fungi refusing to make a start in life until 
there is some chance of success. The cases referred to are those 
in which the spores only germinate in a nutrient solution ; the 
presence of food gives them a signal that it is safe to make a start„ 
If they arc in pure water, it is, figuratively speaking, better policy 
to wait. The resemblance to etiolation is clear ; the gemma or 
spore which cannot germinate until it receives a certain signal, 
behaves like those leaves which refuse to grow until they are 
stimulated by the presence of light. These examples are moreover 
useful as showing how widely spread is the principle of dependence 
* For tlio sake of those readers wlio are unused to the modern points of 
view of plant physiology, it is worth while to state that the power of reply- 
in^,' to a signal or stiirnilus does not i)L tJit: least imply the existence of 
consciousness. Nor does the fact that the behaviour of a plant under given 
conditions is of such a nature as to give the best chance of })reserving the 
life of the individual, or of continuing the species, imply anything of the 
sort. 
