316 * CALAMARIEAE. 



to allow that these have any systematic value, Weiss l shows that this is 

 virtually because he has united a number of badly identified specimens into 

 one species. At all events Stur has not found a better character for the 

 distinction of species to take their place. 



Weiss then distinguishes four form-groups, genera if we like to call 

 them so, of a provisional character. The first of these, named Stylo- 

 calamites, Weiss, and embracing the typical forms Calamites Suckowii and 

 C. arborescens, Stbg, is characterised by the unusually small number of 

 branches on the stems, which for long distances may sometimes be entirely 

 without a branch. The pillar-like stems are composed of shorter and longer 

 members without regularity in their succession ; the ribs alternate regularly 

 at the nodes. The chief example of the second group, Eucalamites, Weiss, 

 is Calamites cruciatus 2 , and Weiss also places in it C. ramosus, Artis. The 

 former species, as 'has been already said, is placed by Grand' Eury with 

 Calamodendron. The pillar-like stems show alternating ribs at the nodes 

 and are copiously branched, one branch springing from each node or several 

 together, which then alternate in the successive whorls. The forms with a 

 few, one to two, branches to each node are classed by Weiss with Calamites 

 ramosus, those with three, four, six or more with C. multiramis, Weiss, 

 which shows the highest number of branch-traces, about nine. A figure of 

 it is given in Weiss 3 . 



Somewhat more of detail is required in noticing the third group Cala- 

 mitina, Weiss (Asterophyllites, Ren., Calamophyllites, Grand' Eury), since it 

 includes all the specimens in which the surface of the stem is seen with 

 the leaves attached. The casts of Calamitinae are chiefly found in col- 

 lections under the name Calamites varians, Stbg, some of them under that 

 of C. approximatus, Brongn. Their distinguishing mark is that branch- 

 traces are not found on every node ; the nodes which have them are 

 separated from each other by a number of nodes on which no branches 

 were formed. The nodes with branches display a great number of scars 

 which are usually in lateral contact with one another. Where the ribs are 

 distinctly shown they alternate in the usual manner. The number of the 

 nodes which intervene between the periodically recurrent whorls of branches 

 is generally constant in each specimen ; there are, as far as is known, two 

 at least and nine at most ; the intermediate numbers three, four, six and 

 eight are frequently observed. The details connected with this point will 

 be found in Weiss 4 . Between the periodic nodes a definite relation is 

 usually apparent in the length of the internodes, which either increases or 

 diminishes from below upwards. 



In this third group, as in all other Calamitae, there is no appearance 

 of the characteristic ribs on the surface of the stem. The surface is either 



1 Weiss (5), p. 141. 2 Brongniart (1), t. 19. " * Weiss (5), t. 12. * Weiss (5). 



