Organography of plants, especially of the archegoniatae and spermaphyta . eafy shoot, aswell as the method of itsorigin. But we do not knowany transition-form betweena rhizophore and a leafyshoot. Even in the germ-plant the rhizophore appearswith the same configurationas it has upon the matureplant. Fig. i66 shows agerm-plant which has de-veloped the first rhizophoreabove the two cotyledons. In favour of its beinga root the anatomical con-siderations have been spe-cially advanced, but thesedo not appear to be recently Bruch-mann ^ has pointed out thatin Selaginella spinulosa, asp
Organography of plants, especially of the archegoniatae and spermaphyta . eafy shoot, aswell as the method of itsorigin. But we do not knowany transition-form betweena rhizophore and a leafyshoot. Even in the germ-plant the rhizophore appearswith the same configurationas it has upon the matureplant. Fig. i66 shows agerm-plant which has de-veloped the first rhizophoreabove the two cotyledons. In favour of its beinga root the anatomical con-siderations have been spe-cially advanced, but thesedo not appear to be recently Bruch-mann ^ has pointed out thatin Selaginella spinulosa, aspecies of radial configura-tion which does not producerhizophores, the roots donot arise immediately fromthe stem, but are produced endogenetically in a cell-body of exogeneticorigin. This body appears in this species as if it were a very short stalkto the root, and it is found also in other species. The rhizophores of dor-siventral species of Selaginella may then be only a further development ofthis stalk in correlation with their life-relationships, and we may compare. Fig. 167. Selaginella cuspidata. The apices of the two shoots of aforked branching were cut off. One of the two rhizophores of the forkWTi, became transformed into a leafy shoot, the other, WTi, didnot develop further; ^Froot. Magnified 9. ^ Bruchmann, Untersuchungen iiber Selaginella spinulosa, A. Br., Gotha, 1897. THE PROTOCORM 251 this stalk with the protocorm of other Lycopodineae. If this be so, therhizophore of Selaginella is neither the result of the transformation of asl^oot nor of that of a root, but is the result of a prolonged growth of anoutgrowth of tissue, which appears in all species, but in the radial formsexists only in a rudimentary condition. Further investigation of the forma-tion of the roots of Selaginella is needed before we can say that this ex-planation is founded upon a right basis. It has, however, the advantagethat it is supported by the comparative consideration of the organs withint
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