322 



CALAMARIEAE. 



might also be inclined to place with Archaeocalamites rather than with 

 Sphenophyllum, will be noticed below. 



The distribution of Calamitae in the series of deposits is comparatively 

 limited, since they cannot be certainly shown to have existed before the 

 Upper Devonian formation and they disappear again before the Trias. 

 Archaeocalamites is the only genus found in the Devonian beds, and in the 

 Culm it is the predominating form. Then its place is taken by Euca- 

 lamitae and Stylocalamitae, which are still represented in the Rothliegende 

 by one very abundant form, Calamites gigas. The Calamitinae also 

 are found throughout the true Coal-measures, but do not reach the Roth- 

 liegende. 



Further, impressions of articulated branches or branch-systems with 

 leaves in whorls are found distributed throughout the Carboniferous 

 formation in equal abundance with the casts of stones ; and these on 

 account of their habit and the striation, like that of Calamitae, which is 

 often to be plainly seen on their older and stronger internodes, it has long 

 been the custom to refer to Calamariae. Though in this case we have no 

 casts, but only impressions on which the substance of the branch is usually 

 preserved as a rind of coal, we may yet unhesitatingly refer the striation, 

 where it is present, to the ribs of the woody body which have left their 

 impression behind them through the thin rind in the stone. It is in ac- 

 cordance with this, that the terminal ramifications usually show no striae ; 

 it may be presumed that no secondary wood was formed in them. 



It has been the custom to distinguish these forms into two groups 

 according to the nature of the leaf-whorls, Annulariae found only in the 

 Carboniferous formation, for Dawson's l Devonian forms can scarcely be 

 taken into consideration, and Asterophyllitae which appear to occur in 

 Devonian deposits 2 . In Annularia, Brongn., all the leaves of the whorl 

 cohere at their base into a small patelliform lamina, which like a flat collar 

 surrounds the stem as it passes through its centre. The leaf-teeth are 

 traversed each by a single nerve, and their form varies with the species ; 

 in the well-known and abundant Annularia Jongifolia, which Rothpletz 3 

 divides into several species, they are elongate-lanceolate and pointed ; in 

 the equally common A. sphenophylloides, Ung., they are much broader, 

 wedge-shaped, and then suddenly contracted, with a blunt rounded ex- 

 tremity. In Asterophyllites, Brongn. (Calamocladus, Schimp.), on the 

 other hand the leaves are quite separated from one another, and they are 

 seldom placed at a right angle to the axis, as in the other genus, but 

 usually incline forwards. They are simple, usually narrow, acicular or 

 linear, of very various but sometimes of considerable length. Good figures 



Dawson (1), vol. i, t. 6. a Dawson (1), vol. i, t. 5. 3 Rothpletz (1). 



