64 STUDIES IN FOSSIL BOTANY 



generic names for the cones, as it is so rarely possible 

 to refer them to particular forms of stem ; while, as we 

 have already seen, some forms of Calamostachys have 

 as good a claim as Palaeostachya to be referred to 

 the genus Calamites. Williamson's specimen has 

 therefore been re -named Palaeostachya vera by Mr. 

 Seward, the specific name serving to recall Williamson's 

 original description of the fructification. 1 



The Calamitean anatomy is shown with great perfec- 

 tion both in the peduncle and in the axis of the strobilus ; 

 in the canals accompanying the vascular bundles, the 

 disorganised spiral tracheae are found, just as in the 

 vegetative stem. In this form the number of sporangio- 

 phores is from sixteen to twenty in each whorl, the bracts, 

 which were connate at their base, being, according to 

 recent observations by Mr. George Hickling, 2 . about 

 equal in number, as are also the vascular bundles in the 

 axis. Fig. 26 represents a transverse section of the 

 cone. The vascular bundles are here approximated in 

 pairs, the pairs alternating, in the nodal region, with so- 

 called canals,, which represent parenchymatous areas in 

 the sclerotic disc which strengthened the node. The 

 peltate part of the sporangiophores is imperfectly 

 preserved in the English specimens, but the sporangia 

 are well shown, and are, as usual, four in number on 

 each sporangiophore. The structure of the sporangial 

 wall is identical with that of Calamostachys. The 

 spores, so far as the existing specimens show, were all 



1 The specific designation pedunculata was inadmissible, as it had been 

 previously given to a different species of Palaeostachya, namely that shown 

 in our Fig. 25. 



2 The anatomy of Palaeostachya vera, Annals of Botany, vol. xxi. 

 July 1907. 



