THE CARBONIFEROUS FLORA. 



123 



late branchlets, or on the lower part of the stem the 

 marks of the attachment of the roots. The Calamites 

 grew in dense clumps, budding off from one another, 

 sometimes at different levels, as the mud or sand accumu- 

 lated about their stems, and in some 

 species there were creeping rhizomata 

 or root-stocks (Figs. 46 to 49). 



But all Calamites were not alike 

 in structure. In a recent paper* 



Fig. 46. — Calamites. 

 a, C. Suclcorii. b, 

 C. Cistii. (From 

 " Acadian Geolo- 

 gy.") 



Fig. 47. — Erect Cala- 

 mites, with roots at- 

 tached (Nova Sco- 

 tia). 



Fig. 48.— Node of C. 

 Cistii, with long 

 leaves (Nova Sco- 

 tia). 



Dr. Williamson describes three distinct structural types. 

 What he regards as typical Calamites has in its woody 

 zone wedges of barred vessels, with thick bands of cel- 

 lular tissue separating them. A second type, which 



* " Memoirs of the Philosophical Society," Manchester, 1886-87. 



