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The Rhizophore of Selaginella. 
Bruchmann found in the case of 5. Kraussiania A.Br. that by 
cutting off the two arms of the stem-fork at an early stage of the 
development of the rhizophore, i.e., before the initials of the 
endogenous roots are laid down, the apical cell of the rhizophore 
becomes that of a leafy shoot and the latter becomes the direct 
continuation of the former. If, however, the root-initials have 
already been formed then the leafy shoot arises laterally and 
below the root-initial, and presses the rhizophore-apex to one side, 
and the latter eventually shrivels up. This phenomenon may, I 
think, be explained on the assumption that, after the root-initials 
are laid down, the rhizophore-apex has become specialised and 
differentiated to form a kind of pseudo-rootcap or protective covering 
of the region where the young roots are forming, and hence has 
lost the potentiality of developing into a leafy shoot. I myself per¬ 
formed a similar experiment to that of Bruchmann with stems of 
5. inequalifolia and S. Mettenii, and with similar results. From all 
the above-cited facts it is clear that the leafy shoot in these cases 
arising on the upper or lower surface of the dorsiventral stem at 
the base of the fork is itself a rhizophore ; the appearance suggests 
unequivocally that the phenomenon before us is not a case of a 
normal rhizophore being first formed which then gives rise by 
transformation of its apex, to a leafy shoot; on the contrary, it is 
clear from direct observation that there is only one organ here 
present. The cases of Neottia, Listera and Anthurium are not to be 
regarded as parallel, for in these there was a clearly-defined organ, 
viz., the root present in the first instance, whose tip developed 
suddenly into a leafy shoot, without any transition whatever between 
the latter and the root; it is most obvious that there are two 
distinct organs present: the terminal shoot in these cases is almost 
certainly an adventitious structure which, at first in its origin 
lateral, has encroached ever more nearly to the apex until it has 
entirely usurped the latter. No interpretation of this sort can be 
placed on the phenomena in Selaginella above described. My 
observations seem to prove unequivocally that the normal rhizophore 
has the morphological value of a shoot. 
Bruchmann caused, in rhizophores whose tips had been cut, 
the formation of fresh roots from the callus. He also induced the 
formation of roots from the ends of stem-cuttings. 
This author has now established that, in the case of all species 
of Selaginella, including S. Martensii (the species investigated by 
Pfeffer) there is (in spite of what Pfeffer described) no radicle or 
