CALAMARIEAE. 309 



a broad base to the node which bears them ; many examples of these 

 branches will be found in Weiss 1 . Sometimes both kinds are observed on 

 the same piece. Where conically narrowed branches are seen in impressions 

 of stems, there are also present almost invariably long usually simple ribbon- 

 like stripes springing from the nodes which bear the branches and from other 

 nodes also, and often crowded together in tufts, which Weiss rightly takes 

 for impressions of roots 2 . Such specimens must therefore be supposed to 

 belong to the subterranean stem. The branches with narrowed conical 

 base which spring from it may then be regarded with great probability as 

 the ascending foliage-shoots, the others as branches of the rhizome with 

 horizontal growth. And it may be further assumed, and not without 

 reason, that fragments which are without roots, but have cylindrical lateral 

 branches not narrowed at the base, arise from the aerial leafy portions of 

 the plant. Their being rarer than the other kind is readily understood, if 

 we reflect that their position in the ground is much less favourable to their 

 breaking up into separate pieces. Weiss 3 has given fine examples of these 

 branches, and Stur 4 likewise. 



It has already been stated that the casts of Calamites are striated 

 longitudinally, the broad convex ribs answering to the medullary rays, the 

 usually narrow acute-angled furrows to the bundles of the medullary sheath. 

 While the striation alternates in the successive internodes, the broken 

 zigzag nodal line is formed in the node and always appears as a deeply 

 incised furrow. This is due to the preservation of the nodal diaphragms. 

 It may however be assumed that these were very generally broken through 

 in the inner central portion in the process of making the casts, for the 

 regular and perfect formation of so many connected internodes could not 

 otherwise be explained, and the close union of the separate internodal 

 members, which never have gaps between them, would be impossible. 

 Deviations also from the regular alternation in the nodes are very 

 commonly to be seen at certain spots in the casts or extending over 

 longer distances, so that the ribs of successive internodes coincide. This 

 is occasionally observed in almost all Calamitae ; Stur 5 has discussed it 

 particularly in the case of his Calamites ostraviensis ; in one form, 

 Archaeocalamites radiatus, it is of regular occurrence, the non-alternation 

 of the ribs in the node being characteristic of the species. 



Where the preservation is good the nodal line is accompanied on both 

 sides by small roundish or ovoid prominences rising above the surface 

 of the cast. They stand in all cases on the back of the broad ribs which 

 answer to the medullary rays, sometimes exactly in the middle, sometimes 

 also on one side, and nearer to the one adjoining furrow than to the 

 other. A small knob of this kind is usually found at the extremity of 



1 Weiss (5). 3 Weiss (6), t. 19, f. la and (5). 3 Weiss (5), tt. 5, 6, 7. Stur (5), 



t. 23, and p. 192, f, 18. 5 Stur (5), pp. 118, 119. 



