GO 



PAL^ONTOLOGICAL BOTANY. 



and Equisetum found in secondary rocks and living at the 

 present day. Tlie difference in the structure of their fruits 





Fig. 47. 



is shown in woodcut 47. The fruit of Calamites, called 

 Volkmannia Binneyi (woodcut 47, 7), is a small slender 

 cone composed of alternating whorls of imbricate scales, 

 twelve in each verticil. The scales completely conceal 



Fig. 47. Fruits of Equisetum and Calamites. 1. Equisetum arvense, 

 L. 2. Portion of sporangium wall. 3, 4. Spores, with the elaters free. 

 5. Longitudinal section of the part of one side of cone. 6. Trans- 

 verse section of cone. 7. Calamites (Volkmannia) Binneyi, Carr., 

 magnified three times. 8. Portion of the sporangium wall. 9. Two 

 spores. 10. Longitudinal section of the part of one side of cone., 

 11. Transverse section of cone. 



