SIGILLARIA 237 



been demonstrated that some species were hetero- 

 sporous, and this was probably the case with all. 



Of no less importance and distinction in the Palaeozoic 

 flora than the giant Lycopods just described was the 

 genus Sigillaria. It included difierent species of tree- 

 like Club-Mosses, some of which were equally as lofty 

 as the tallest Lepidodendrons, while others appear to 

 have been more stout and stumpy. Sigillaria reni- 

 formis was of the latter habit. A trunk found in Ger- 

 many is described as being 6 feet in diameter at its 

 base, but it tapered off rapidly to a diameter of 1 foot 

 at the height of 18 feet. Another trunk, found in 

 France, near Valenciennes, for a length of over 70 feet 

 was almost cylindrical. At the lower end it was about 

 2 feet in diameter, while at the other extreme it was 

 1 foot 8 inches; it was entirely unbranched. It would 

 appear that as a rule the Sigillariw were lofty trees 

 with scantily branched, pillar-Hke stems and linear 

 leaves, which were, in some instances, over 3 feet in 

 length. The fructifications were conelike, about 

 9 inches long; they were borne on long stalks attached 

 to the stem, and consisted of spirally arranged or whorled 

 sporophyUs protecting sporangia. The leaf-scars, which, 

 like those of Lepidodendron, are conspicuous in the 

 fossils, differ in their arrangement from those of that 

 genus. They are arranged in vertical order, as shown 

 in Fig. 74, whereas in Lepidodendron the arrangement is 

 oblique or spiral. The distribution in time seems to 

 have been more restricted in Sigillaria than in the Lepi- 

 dodendra ; the former have not been traced with cer- 

 tainty below the Carboniferous, and they probably died 

 out in Permian times. 



