204 KIDSTOX: THE FLORA OF THE CARBONIFEROUS PERIOD. 
Macrostdchya Schiraper is another genus of Calamitic cones. 
These attained to considerable size, and are much larger and 
broader than those of the three preceding genera. The cones are 
composed of alternating closely placed verticils of many bracts, 
united to each other throughout the greater portion of their 
length ; only the short upturned extremities of the bracts remain 
free. Each whorl of bracts thus forms a saucer-like collar which 
surrounds the thick axis of the cone. The arrangement of the 
sporangiophores has not been clearly made out. 
Other types of Calamitic cones are known, but those mentioned 
are the principal forms which occur in British Carboniferous rocks. 
Occasionally specimens of Calamites are found showing the 
remains of their rootlets. These are — in whole or in part — the 
fossils for which Lindley and Hutton founded the genus Finnularia 
(Plate XXXY., fig. 1 — Pinnularia columnar is). They consist of 
roots pinnately giving off lateral roots, which in turn bear the 
rootlets, apparently in the same plane. 
That the Calamariece and Equisetacece. are closely related is 
beyond all doubt, and there seems to be no satisfactory reason why 
they should not be united in one family under either of these 
names, preferably under that first mentioned. 
The genus Calamites seems to have entirely disappeared with- 
out leaving any modern representative, while the less important 
palaeozoic genus Equisetites is probably the ancestor of the recent 
Equisetum. 
