376 



EQUISETALES 



it. In fact it is to be recognised that, speaking of the bracts, " a tendency 

 to multiply the number of appendages in each whorl seems to have been 



Archaeocctlajiiites. Part of 

 cone showing the axis (ax) 

 in surface view, bearing 

 superposed verticils of peltate 

 sporangiophores (sp) without 

 bracts, sm sporangia. (After 

 Renault.) From Scott. 



FIG. 202. 



Calamostachys. Diagram- of 

 cone in radial section. a.r = axis, 

 which bears successive vercicils of 

 bracts (br), and peltate sporangio- 

 phores (sp). sm sporangia borne 

 on the sporangiophores. As the 

 bracts are alternate with one 

 another their upturned tips are 

 only shown in every alternate 

 verticil. (After Scott.) 



FIG. 207. 



Palaeostacliya. Diagram of cone 

 in radial section. ax axis, which 

 bears verticils of bracts (l>r) with 

 peltate sporangiophores (s/>) in 

 their axils, sm = sporangia. (After 

 Renault.) From Scott. 



a characteristic Calamarian feature." 1 There appears, consequently, to 

 have been no constant relation either of number or of radial position 



between the bracts and the 

 sporangiophores. 



The relation of these 

 two parts as regards vertical 

 position is also variable 

 within the fossil Equise 

 tales ; for, as is well known, 

 the sporangiophores occupy 

 in Palaeostachya a position 

 at the base of the internode 

 (Fig. 203), in Calamostachys 

 p. 882. 



Cingularia, typica, Weiss. From the Westphalian. Diagrammatic 

 drawing of part of a shoot. X about 2. After Weiss. 



1 Hickling, Ann. of Bot. , 1907, 



