HORSETAILS 199 



same form of fructification. M. Halle has made a 

 careful examination of the shield-like scales, in a 

 Rhsetic species; they show no important differ- 

 ence from these organs as they exist now, except 

 that the number of sporangia on each scale was 

 greater. 



In Schizoneura, a characteristic Triassic genus, 

 especially common in the East, the leaf sheaths 

 were split into irregular, leaf-like segments, and 

 in the Rhaetic Neocalamites the leaves were per- 

 fectly free, long and narrow, not forming a sheath 

 at all. In this genus, as hi the contemporary 

 Equisetltes already referred to, the vascular 

 strands were two or three times as numerous as 

 the leaves in a whorl; in fact Neocalamites, so 

 far as its characters are known, was almost 

 identical with the Palaeozoic genus Calamites. 

 In the Triassic Flora the modern and ancient 

 types meet, and there are some signs of transi- 

 tion from the one to the other, though not yet so 

 complete as we could wish. As M. Halle has 

 pointed out, there is no reason to doubt that we 

 have a direct line of descent from the gigantic 

 Triassic Equisetites to the Horsetails of our own 

 day. The link between the Triassic plants and 

 the still more highly developed Calamites of the 

 Primary Rocks is not yet perfect, though Neo- 

 calamites and Equisetites scanicus come very 

 near to connecting the two types. 



