iqiqI BASSLRR—SPORANGIOPHORIC LEPIDOPHYTE 89 



ancestor the Calamariales suggest themselves. Is there further 

 evidence to show that the former is near such a line of descent? 

 Unfortunately we have here no structural material which might 

 show us stages in the development of the sporangium, but in mature 

 sporangia of our collections the distinct median longitudinal furrow 

 regularly encountered in several of the species may have significance 

 in this connection, and the differentiation of the face of the sporan- 

 giophore into two more or less distinct fields might have some bear- 

 ing on this matter, and it is perhaps not a mere coincidence that 

 these fields are most sharply marked in one of the oldest known 

 species, C. mirabilis from the Lower Carboniferous. While such evi- 

 dence for a tetrasporangic ancestor for Cantheliophorus and through 

 it for the Lycopods is exceedingly weak, it cannot be ignored. 



In Cantheliophorus the sporangiophore is dorsiventral, while 

 the symmetry of this structure in the most abundant of the Cala- 

 mariales, Palaeostachya and Calamostachys, with a few exceptions 

 is radial, and unless we can indicate a form somewhat intermediate 

 between types of such essential difference, theories involving their 

 affinity must remain inconclusive. Calamostachys (Arthropity- 

 stachys) Grand' Eur yi Renault and Calamostachys {Arthropity- 

 stachys) Decaisnei Renault (19, 21), two species based upon 

 petrified material from Saint-Etienne, appear to constitute such 

 an intermediate type, for in each there is a stout plate of sterile 

 tissue singularly like the sporangiophore of Cantheliophorus, which 

 spans more or less completely the space between the sporangiophore 

 and the bracts of the whorl above, interjx)sing a vertical wall 

 between sporangia borne distad upon the same sporangiophore. 

 There is slight development also of similar tissue in this plane 

 beneath the sporangiophore (fig. 7,^. Even though it be admitted 

 that these 2 species may possibly lie near the line of descent, it 

 may be objected that there is still a great fundamental difference 

 between them and Cantheliophorus, inasmuch as the arrangement 

 of the sporophylls is verticallate in one case, while it is spiral in the 

 other. Such an objection, however, might easily be dismissed with 

 a reference to Spencerites, a form with verticillate sporophylls, 

 which has been placed without question in the exclusive group of 

 the Lycopods. 



