STIGMARIA 261 



and parichnos, and the course of the rootlet-traces. 

 There is no analogy among the Lycopodiales for such 

 a modification of a leaf, but the water-leaves of Salvinia 

 might be cited as remotely comparable. The presence 

 of leaf-like characters in the Stigmarian appendages 

 may be in part the survival of a more primitive 

 morphology, but on the whole it seems evident that 

 they are the same organs as the roots of recent Lycopods. 

 Their apparently exogenous origin offers no hindrance 

 to this interpretation, for we know that among recent 

 Lycopods, as in Selaginella and Pkylloglossum, roots 

 may arise exogenously. 1 



What view, then, are we to take of the organs which 

 bore the appendages ? They are, as we have seen, often 

 very different from typical roots. Neither, however, do 

 they show the characters of rhizomes ; they bear no 

 . leaves, and we have no convincing proof that they gave 

 rise to aerial stems, though it is possible that they 

 may have done so. Those Stigmariae, however, the 

 relations of which are the most clear, are beyond doubt 

 appendages of the aerial stems, and not their parent 

 organs. How those stems arose in the first instance, 

 whether directly from the embryo, or from some 

 creeping form of axis, of which, as a rule, no traces 

 remain, 2 is at present an unsolved problem. 



It appears, then, that the main Stigmariae cannot 

 be classed morphologically either as roots or rhizomes. 



1 Van Tiegham et Douliot, " Origines des membres Endogenes," Ann. 

 des sci. nat. [Bot.),stx. vii. vol. viii. p. 552, 1888; Bower, "On the 

 Development and Morphology of Phylloglosstim Drummondi" Phil. Trans. 

 ii. 1885. 



2 M. Grand'Eury maintains the latter view. See his Bassin houiller du 

 Gard, p. 236 ; also " Sur Ies Sols de Vegetation fossiles des Sigillaires et 

 des Lepidodendrees," Comptes Rendus, t. cxxxviii. 1904. 



