266 



Mc/^oiia/(f : T/ic Doo's Mercury. 



apical leg may assist in pushing the arcli njnNards. But even 

 if this possibilit}^ be acknowledged, the longer basal leg exerts 

 the greatest force as the young leaves of the apical leg are not 

 sufficiently rigid to offer any great support. 



There is also the probability that a side to side movement 

 (nutation) as far as the soil will allow, assists the rising arch in 

 displacing the soil. Suppose a longitudinal half of a leg is 

 growing quicker than the other half, say the outer half of the 

 basal leg, the arch would be pushed towards the apical leg, 

 and in this it might be assisted" by the inner half of the apical 

 leg gromng quickest. Suppose the first figure (Fig. 8) presents 

 the legs and arch when the latter is not leaning either way, 

 then the state just mentioned might be represented by the 

 middle figure ; when the reverse portions were undergoing quick- 

 est growth the arch would be pushed over to the basal leg as 

 in the third figure. 



Such a procedure is many times repeated, though more 

 complicated than just described, until the arch and apical 

 leg are well out of the soil when, having reached the light, the 

 whole inner surface grows quickest until the stem is erect. 



The fact that the stem often remains arched for some time 

 even after having emerged from the soil is suggestive that this 

 may be a means of protection against miniature landslips, a 

 feature so often noticeable about this season on the banks of 

 wooded ravines which it often frequents. It may be observed 

 further that when a portion of the rhizome, as occasionally 

 happens, is not actually buried the shoots developing from it 

 grow for some time in the same arched manner, and further, 

 when a seedling has its seed leaves above the soil the plumule 

 behaves similarly. This same bending, too, in conjunction 

 with the rolled leaves, is a protection against chill by radiation 

 of heat, and prevents the leaves from becoming wetted with 

 cold rain, etc. 



The internodes of the underground portions of stem are 

 from two to five inches long in a loose soil, rather shorter in a 



Fig. 8 (For explanation see text). 



Naluralist. 



