W. Carruthers — The Forests of the Coal Period. 295 



ture has not liitlierto been determined. The different forms have 

 been placed together as allied genera, and have been referred, by 

 those who have specially studied them, to the phanerogamous Order 

 Hatoragacece near to the Water Milfoil (Myriophyllum) , with some 

 species of which they agree very remarkably in the arrangement 

 and aspect of their foliage and fruit.^ 



W.&.SM1TH.DEL 



Plate II. — Fruits of Equisetum and Calamites. 



Fig. 1. Equisetum arvense, L. 2. Portion of the sporangium ^vall. 3. Spore, 

 ■with the elaters free. 4. Spore with the elaters clasping. 5. Longitudinal section 

 of the part of one side of cone with three fruit-bearing scales supporting sporangia. 

 6. Transverse section of cone. 7. Calamites ( Volkmamiia) Binneyi, Carr., magnitied 

 three times. 8. Portion of the sporangiiun wall. 9. Two spores, one showing the 

 bases of two elaters free, the remainder being removed in slicing the fossil, and the 

 other showing the elaters clasping. 10. Longitudinal section of part of one side 

 of cone with three fruit-bearing and four simple leaves. 11. Transverse section of 

 cone, showing six fruit-bearing leaves and twelve protecting scales. 



The determination of the internal structure of one of these fruits 

 which I made, first from specimens collected by Mr. Binney, and 

 have since confirmed from specimens which have been some years 



^ Monographic des Sphenophyllum d' Europe. Par E. Coemans and J. J. Kickz. 

 Bulletin Acad. Eoy. de Belgique, 2nd Ser. vol. xviii. (1864), No. 8. 



