SIGILLARIA 231 



differences. In all other respects their structure is 

 that of a Sigillarian leaf (see the details in Fig. 95). 

 The name Sigillariopsis sulcata 1 has been given to 

 the English species, for the leaf has two stomatiferous 

 furrows, as in Sigillaria or Lepidodendron. Sigillariopsis, 

 which may correspond to a part of Sigillaria, is inter- 

 esting from its analogies, in certain points, with the 

 structure of some of the Coniferae, with which, however, 

 an affinity is improbable. There is good evidence that 

 the British Sigillariopsis was borne on the stem known 

 as Sigillaria scutellata (or some closely allied species), 

 in which, as Arber and Thomas have shown, the double 

 leaf-traces are quite similar in structure to the double 

 bundle of the leaf. It thus appears that the 

 Sigillariopsis type of leaf probably occurred both on 

 Eusigillarian and Subsigillarian stems. The double 

 bundle is an important character, and may prove to 

 be of generic value. 



3. Fructifications. — Our examination of Sigillaria 

 has shown us, up to the present point, a very close 

 agreement with Lepidodendron, as regards the external 

 morphology and the anatomy of stem and leaf. It is, 

 however, on the character of the fructification that the 

 determination of the systematic position of the genus 

 must ultimately depend. This knowledge we owe 

 primarily to M. Zeiller, who in 1884 first demonstrated 

 the nature of the cones of Sigillaria'} Before that date 

 several specimens had been described as Sigillarian 



1 Scott, " On the Occurrence of Sigillariopsis in the Lower Coal-measures 

 of Britain," Ann. of Bot. vol. xviii. 1904. 



2 "Cones de fructification des Sigillaires," Ann. des sci. nat. {Bot.), 

 ser. vi. vol. xix. 1884. 



