GENERAL MORPHOLOGY 



375 



of twelve coherent leaves, but thirteen have been counted : the sporangio- 

 phores are usually six, that is, half the usual number of the leaves of the 

 sterile whorls; but seven and eight have been seen in a single whorl of 

 them, while no whorl of sixteen bracts has been seen. Hence it is clear 

 that the sporangiophores bear no strict 

 numerical relation to the sterile bracts. 

 The position of the bracts in successive 

 whorls of them alternates : the successive 

 whorls of sporangiophores, on the other 

 hand, do not alternate, " but are placed one 

 above the other in vertical rows. Hence it 

 is evident that their position can bear no 

 constant relation to that of the bracts." 1 



This absence of a strict relation of the 

 sporangiophores to the bracts comes out 

 also in C. Linhvigi, described in detail by 



Weiss. 2 He remarks of this species that 



the number of leaves in the sterile whorl is 



evidently variable : he made several count- 

 'ings, and concludes, " accordingly it may 



be accepted that there were sixteen leaves 



in the whorl, but that they might be re- 

 duced to twelve (or thirteen?) by abortion 



of some of them." The leaves of the 



neighbouring whorls certainly alternated. 



Of the sporangiophores he says, the number 



in each whorl is six, and the successive 



whorls of sporangiophores stand vertically 



above one another ; but he notes slight 



deviations from this, perhaps due to torsion. 



A still further step is depicted by Weiss, ;s 



in the case of Calamostachys germanica, 



where apparently the narrow bracts are 



approximately three times the number of 



PalaeostachyapedunCTilata. Specimen 



the sporangiophores; but this is not speci- jSt ^5^ S w SK 



firallv t:tnt-i>rl ro he the ra<;e in the tevr few le ^ves. X- = stem. About two-thirds 



ICaliy Stati ie\t. nat ural size. (Afu-r Williamson, Phil. 



On the other hand, it has been shown Trans, irni. Coil ^.) From Scott's 



Studies in Passil botany. 



clearly in the case Palaeostachya i'crn that 



the number of bracts approximately corresponded directly to the number 



of sporangiophores, though possibly in some cases they somewhat exceeded 



1 Williamson and Scott, " Further Observations on the Organisation of Fossil Plants, etc.," 

 part i., /'////. Trans., 1894, B, pp. 902-3. See also Scott, Sfinfics, p. 47, etc. 



2 Abhandl. z. Ccol. Spezialkarte, vol. ii., part i., p. 38. 

 3 L.i., vul ii., part i., Taf. xvi., Fig. 3 i;. 



