376 CALAMITES. [CH. 



sti'obili of C. Suckowi, but Stur adduces evidence in support 

 of a connection between this species of Calamite and certain 

 Asterophyllitean branches {Calamocladus equisetiformis) bear- 

 ing Calamostachyan cones. He does not appear to have found 

 the foliage-shoots and stems in organic contact, but draws 

 this conclusion from the association of the fertile branches and 

 stems in the same rocks \ This species is abundant in the 

 Lower, Middle and Upper Coal-Measures ; it has also been 

 recorded from the Millstone Grit^ 



C. Eucalamites. 



In this sub-genus branch-scars occur on every node ; the 

 scars never form a contiguous whorl as in Calamitina, but 

 there may be from 3 to 10 on each node. The scars of 

 successive nodes often alternate in position, and thus form 

 more or less regular vertical series as shown in fig. 102. 

 The most obvious feature as regards the arrangement of the 

 branch-scars is their spiral disposition on the surface of the 

 pith-cast. The intemodes are fairly uniform in length, and 

 there is no periodic recurrence of narrower internodes as in 

 Calamitina. From an examination of specimens of Eucalamites 

 in which the pith-cast is covered with a coaly layer representing 

 the carbonised remains of the wood and cortex, it would appear 

 that the surface of the stems was practically smooth. The 

 coaly investment on Eucalamites casts varies- considerably in 

 thickness^; it is very unsafe to make use of the thickness of 

 this layer as a test of the breadth of the wood in Calamitean 

 stems. The branch-scars as seen in a surface-view of a stem 

 are situated a little above the nodal lines, while depressions on 

 the pith-casts occur in the slight nodal constriction or immedi- 

 ately above it. Small leaf-scars have been described as occurring 

 on the nodes between the branch-scars in specimens showing the 

 surface features'*. 



The species long known as Calamites cruciattis Sternb. is 

 usually taken as the type of the sub-genus Eucalamites. 



Stur (87), p. 160, PL ix. fig. 2. ^ Kidston (94), p. 249. 



Grand'Eury (89), p. 1087. "» Zeiller (88), p. 355. 



