198 KIDSTON: TUK FLOHA of TIIK CAKHOXIFKKUUS PEUIOU. 



iiKule ill the study of pahrozoic botany, and to the Cycadofilices 

 are known to belong certain ^phenopteris, Alethopteris, and 

 Xeuropteris. 



As an example of how step by step our knowledge of 

 paheozoic- l)otany is l)uilt up, it may be mentioned that the 

 petioles described by Williamson as Rachiopte7'is aspera were 

 subsecjueutly found to belong to the stem named Lyginodendron 

 Oldhamium by the same author, and furtlier it has been dis- 

 covered that Lyginodendron Oldhamium is the stem of the 

 well-known Sphenopteris Iloeninghausi Brongt. {Plate XXIX., 

 fig. 5). Could any better example be found of the result — or 

 reward — of patient, plodding work, or of the provisional nature 

 of genera founded on the vegetative organs ? 



Calamarie^. 

 Equisetites Sternberg. 



A few fossils have been found in Carboniferous rocks which 

 from their great external resemblance to the recent Equisetum 

 or Horsetails, have been placed in a genus called Equisetites by 

 Sternberg. These fossils are extremely rare, and as far as at 

 present known do not go furtlier back than the Coal Measures. 

 One of the most interesting examples of the genus is the 

 Equisetites Hemingwayi (Plate XXXIV., fig. 3), which was dis- 

 covered by Mr. Hemingway, Barnsley. 



The cones are oval, about one inch long and rather over 

 half an inch broad. The outer surface of tlie cone is covered 

 with hexagonal scales about one-fifth inch in diameter, with a 

 small central point, indicating probably the place of attachment 

 of the little pedicel by which the peltate shield was united to 

 the axis of the cone. Nothing is known of the inner structure 

 and arrangement of the sporangia, but the external appearance 

 of Equisetites Hemingwayi is so like that of the cones of recent 

 Equisetum (of which a figure is given for comparison, Plate 

 XXXIV., fig. 4, Equisetum hyemale), that the atfinities of 

 Equisetites Jlemingwayi Kidston with Equisetum is probably 

 very close. 



