﻿Dictyophlois reticulata gen. et sp. nov. 



Aug. F. Foerste 



(WITH PLATE 33) 



The name Stigmaria ficoides Brongniart at present does service 

 in designating the so-called roots of both of the genera of stems 

 known as Lepidodendron and Sigillaria. Not only have these 

 roots been found in direct connection with the Lepidodendron 

 and Sigillaria stems but it has been found impossible so far to 

 discover any specific or generic differences in the roots so con- 

 nected. 



The genus Lepidodendron makes its appearance in the Lower 

 Devonian and dies out in the Permian. Recently Dr. David White 

 has called my attention to the fact that in Mississippian or Sub- 

 carboniferous specimens of Stigmaria ficoides the characteristic 

 round scars, indicating the points of attachment of the so-called 

 rootlets, are distinctly smaller than in Pennsylvanian or Coal 

 Measure representatives passing under the same name. 



Students of the microscopic structure of Stigmaria and of its 

 rootlet-like appendages, regard the latter as homologous with the 

 monarch roots of certain living plants, so that the main axes of 

 the so-called roots known as Stigmaria should be known as rhizo- 

 phores rather than roots. There is a possibility that these rhizo- 

 phores represent underground stems, but this still is a debatable 

 question. 



In the vicinity of Sample, two miles east of Stephensport, 

 Breckenridge County, western Kentucky, the rhizophores of both 

 Stigmaria ficoides and of an undescribed but related genus occur 

 in one of the sandstone layers belonging to the lower part of the 

 Chester division of Subcarboniferous rocks. 



The undescribed rhizophores resemble those of Stigmaria ficoides 

 in possessing small ring-like areas of attachment of the monarch 

 roots, the latter being arranged in diagonally intersecting rows. 

 In several of these ring-like areas a minute central point could be 

 recognized, but the smaller ring, which in Stigmaria intervenes 

 675 



