A TYPE OF PALAEOZOIC PLANTS. 



IN the H of- Museum of Vienna there are some well- 

 executed and striking wall paintings of Upper Car- 

 boniferous scenery, designed by Hoffmann, under the 

 direction of the late Dr. Stur. Arborescent Lepidoden- 

 drons, Sigillarias and Calamites occupy the most prominent 

 position ; and with the large-leaved Cordaites these plants 

 probably formed the most conspicuous types in the Upper 

 Palaeozoic forests. Some of the Calamites are represented 

 with tall ribbed stems, bearing lateral branches and cones of 

 various forms ; among the calamitean foliage we notice the 

 well-known wedge-shaped leaves for which Brongniart, in 

 1822, instituted the genus Sphenophyllum. 



Restorations of this kind have been attempted by 

 numerous artists, inspired by widely different views as to 

 the actual appearance of the commonest Coal- Measure 

 plants. In many respects the Viennese pictures may no 

 doubt be regarded as a closer approximation to the truth 

 than most of the earlier attempts, but in certain particulars 

 they are still far from photographic accuracy. It is quite 

 clear, from what we know of the structure of calamitean 

 plants, that in most forms the external surface of the stem 

 did not show any signs of the ridges, grooves or nodal 

 constrictions which form such characteristic features of the 

 common medullary casts. It may be that in some species 

 the stem was slightly ribbed, as suggested by Weiss l and 

 other writers, 2 but in the great majority of calamitean 

 plants the surface was no doubt smooth. According to Stur, 

 Asterophyllitcs and Anmtlzria, with their univeined leaves, 

 should be regarded as the homomorphous branches of 

 Calamites. while Sphenophyllum, with broader leaves usually 

 traversed by several veins, represents a heteromorphous 

 form of calamitean branch. Stur's views as to the con- 



1 Weiss (2). 



- Kidston, Trans. Geo/. Soc. Glasgow, vol. viii., p. 52. 



