368 



CALAMITES. 



[CH. 



branch-whorl is situated immediately above a node, and in 

 some forms this nodal line pursues a somewhat irregular course 

 across the stem, following the outlines 

 of the several branch-scars\ The 

 surface of the internodes is either 

 perfectly smooth or it is more fre- 

 quently traversed by short longitu- 

 dinal ridges or grooves probably 

 representing fissures in the bark 

 of the living stem ; these are indi- 

 cated by lines in fig. 99 and by 

 elongated elliptical ridges in fig. 101. 

 On young stems the leaves are 

 occasionally found in place, as for 

 example in an example figured by 

 Weiss- (C. Gopperti), or we may have 

 leaf-verticils still in place in much 

 older and thicker branches^ (cf fig. 

 85, p. 330). 



It occasionally happens that the 



bark of Calamitina stems has been Fig- 99. Calamites {Calamitina) 



preserved as a detached shell* re- '^opP^rtHmt.). 6, branch scars. 



. T . , , p T-.- 1 From a specimen in the 



mmdmg one of the sheets of Birch Manchester Museum, Owens 



bark often met with in forests, the College. J nat. size. 

 separation being no doubt due in 



the fossil as in the recent trees to the manner of occurrence 

 of the cork-cambium. 



In a few cases branches have been preserved still attached to 

 a stem or branch of higher order; examples of such specimens are 

 figured by Lindley and Hutton^, Stur", and others. Grand'Eury' 

 has given an idealised drawing of a typical Calamitina bearing 

 a whorl of branches with the foliage and habit of Asterophyllites 

 equisetiformis. The specimen on which this drawing is based 



> Vide Weiss (84), PI. xxv. fig. 2; PI. xvia, etc. 



' Weiss (76), PI. xvii. fig. 1. 



■» Grand'Eury (90), p. 208, and (77), PI. v. 



= Lindley and Hutton (31), PI. cxo. 



' Grand'Eury (77), PI. iv. 



s Weiss (84), PI. i. 

 Stur (87), PI. V. fig. 1. 



