374 EQUISETALES 
The Calamarian strobili were terminal on the axes, but they bad a more 
elongated form than is usual in Zgucsetvum (Fig, 200): sometimes they 
Fic. 198. 
Schizonenra Godwanensis. Two-thirds the natural size. (After O. Feistmantel, from 
Engler and Prantl, Nat. Pflansenfan.) 
extended to a length of 30 cm. (Potonié). They differed also in their 
construction: the nearest to the Lgu/setum-type is the ancient Archaeo- 
calamites (Borniz),) characteristic of the oldest 
Carboniferous strata, and of the upper Devonian 
(Fig. 201). Its strobilus is essentially like that 
of Equisetum, having no sterile bracts intervening 
between the whorls of eight to ten sporangio- 
phores. These whorls did not alternate, but 
neither did the whorls of branched leaves in this 
early type. Here it would appear that there is a 
more complete differentiation of the reproductive 
from the vegetative region than is the case where, 
as in other Calamarians, sterile bracts are dis- 
tributed throughout the strobilus. 
di staroenlanities screbicniatys: The latter was the more prevalent type 
Schlotheim (sf) from the culm. 
Fragment of a leafy shoot, re- 9 eee Sass a ; 
Frasment ON it naneel sie, among the early Equisetales: in them the sterile 
(After Stur, from Zeiller, Pao. Jeaf-whorls and the whorls of sporangiophores 
botanique.) 
regularly succeeded one another, as it is seen 
in Calamostachys, and is well shown in C. Binneyana, which is the 
best known type (Fig. 202), The sterile whorls are commonly composed 
I Renault, Basse Houtller et Permien ad’ Autun et d Epinac, vol. ii., p. 80, Plate 42. 
