14 Arber, Fossil Plants from the Ardwick Series. 



certain species of the recent Equisetum, in which the free 

 segments are much reduced, and the sheath especially- 

 prominent. It may be that in certain species oi Calamites 

 a similarly reduced type of leaf-whorl is borne on certain 

 branches. I merely wish to point out here that these 

 particular forms of Calamitean foliage differ markedly 

 from the commoner types of Calamocladus and Annularia. 



Palceostachya Weiss, 1876. 

 Steinkohl. Calamitien (i) p. 103 ; (2) p. 161. 



PalcBostachya sp. 

 {d) Sedgwick Mus. Camb., Carb. Plant Coll., No. 

 1 127 (figured). 



ih) Manchester Museum, Owens College. 



Figured, Binney, Observ. Struct. Foss. Plants, 

 Part I. (Pal. Soc), 1868, PI. vi., Fig. 4. 



Mr. Kidston,^ on the evidence of Binney's figure, 

 referred this plant to PalcBostachya pedunculata Will, in 

 1 89 1. I have, however, recently shown him the actual 

 specimen, which he thinks is too imperfect for specific 

 determination. We are both agreed however that the 

 cones belong to the genus PalcEostachya, and are possibly, 

 but not certainly, P. pedunculata Will. The interest in 

 this specimen lies in the fact that the foliage of the cone- 

 bearing branches, although too imperfect for determination, 

 rather recalls the type of foliage just described as Annu- 

 laria stellata, whereas the fructification belonging to that 

 foliage is known to be Stachannularia tuberculata Sternb^ 

 It is possible that there may be other types of foliage 

 closely resembling A. stellata, which are very difficult or 

 impossible to distinguish from it when preserved as 

 impressions. 



1 Kidston ('91), p. 418. 

 - See Kidston ('94), p. 584. 



