236 Mr Thomas, On a specwien of the cone 



On a specimen of the cone Calamostachys biune3^aua (Garr.). 

 By H. Hamshaw Thomas, B.A., Downing College. [Communicated 

 by Mr E. A. Newell Arber.] 



[Bead 3 May 1909.] 



Forty years have now elapsed since the first description of the 

 cone Calamostachys hinneyana was published*, but hitherto no 

 petrified specimen has been found showing its connection with 

 vegetative organs of any kind. 



In December last, I received a specimen of a cone with four 

 whorls of Calamite leaves attached to the base, derived from the 

 Halifax Hard Bed at Huddersfield. The cone was at least 14 mm. 

 long and about 5 mm. broad. It was cylindrical in shape and 

 eight whorls of sporangiophores are preserved. 



The structure of the cone agrees closely with that of specimens 

 previously described f, and the axis and sporangiophores do not 

 present any unusual features. Several of the bracts are very well 

 preserved and show some new points of interest. As usual, they 

 are coherent at the base to a disc, and, on becoming free, turn 

 sharply upwards. Each is provided with a vascular bundle, the 

 centre of which is occupied by a group of very small xylem 

 tracheides surrounded on all sides by small thin-walled cells, 

 probably phloem. The bundle may possibly therefore be con- 

 centric in structure and not collateral as formerly supposed, though 

 it is very difficult to arrive at any certain conclusion. The free 

 portion of the bract bears a striking resemblance to a leaf. It 

 consists largely of sclerenchymatous fibres on the adaxial side, 

 while a layer of rudimentary pallisade tissue forms the other side. 

 The small bundle occurs in the centre of the bract, and on the 

 inner side of the pallisade tissue, a zone of cells with dense black 

 contents is found. There is a thin epidermis on the outside. 



At the base of the cone, there is a whorl of bracts resembling 

 the leaves still more closely. Immediately below this we have a 

 whorl of appendages differing completely from the leaves, bractS; 

 and sporangiophores, and seen in longitudinal section as a broad 



* Carruthers, W. " On tlie fruit spike of Calamites." Journal of Botany, 

 vol. V. 1867. 



t Bmney, E. W. "Observations on the Structure of Fossil Plants." Mem. 

 Palaontographical Soc. p. 24. 1868. Williamson, .W. C. " On the organisation 

 of the Fossil Plants of the Coal measures," Parts iv. x. xi. xv. Phil. Trans. 1873, 

 1880, 1881, 1889. Hick, T. " On Calamostachy.'; binneyana." Proc. Yorks. Geol. 

 and Polyt. Soc. vol. xii. pt. iv. 1893. Williamson, W. C. and Scott, D. H. 

 " Further Observations on the organisation," etc. Phil. Trans. 1894. 



