CARBONIFEROUS LYCOPODS AND SPHENOPHYLLS. 



Ill 



Both rhizome and "tap-roots" have a central core, whose cast 

 is ribbed something like a calamite stem, but without any joints. 

 The ribbing differs, however, from that found on calamites. On 

 the casts of the pith cavity of Stigmariopsis the ribs are separated 

 by square-based furrows which are rather wider than the ribs. 

 These furrows are finely but strongly striated longitudinally. 

 The ribs when well preserved are also longitudinally striated. 



The cores discovered in the specimen examined by Solms- 

 Laubach were covered with a layer of structureless bright coal, 

 from 1 to l - 5 mm. thick. CBS^r— - , 

 The outer surface of this R 

 coaly envelope bears linear 

 club-shaped depressions 

 placed in upright rows, 

 which are connected in ver- 

 tical series by a shallow tail- 

 like extension of the depres- 

 sion. In addition to the 

 upright series, these depres- 

 sions show oblique spiral 

 arrangements in their lateral 

 position to each other. The 

 space between these depres- 

 sions is finely striated with 

 slightly wavy lines. 



The calamite-like cast is 

 the impression of the pith 

 cavity, and the coaly envelope 

 represents the xylem portion of the bundle. The remainder and 

 much larger portion of the rhizome is composed of cortex. 



So much for our knowledge of the structure of Stigmariopsis 

 — very imperfect, it is true — but it is sufficient to distinguish it 

 clearly from Stigmaria. 



Solms-Laubach has also thrown out the suggestion that the 

 plant whose structure has been described by Renault, under the 

 name of Stigmaria flexuosa may be a Stigmariopsis} 



If any doubt remains as to Stigmaria flexuosa, Renault, 

 being a Stigmariopsis, I think there can be little doubt that the 

 1 Uber Stigmariopsis, Grand ! Eury, p. 15. 



Fig. 20. — Stigmariopsis. Cast of the 

 pith cavity, from a specimen com- 

 municated by Graf Solms-Laubach 

 from one of the examples described 

 in his paper, " Uber Stigmariopsis. 

 (No. 2601.) 



