CALAMOSTACHYS S3 



the nodes, but go straight down the axis. We see, 

 however, that the anatomy, on the whole, is quite 

 consistent with that of the Calamitean type of stem. 



We will now pass on to the structure of the 

 appendages, and will take the sterile bracts first. In 

 our species (C. Binneyand) the bracts are coherent for 

 a considerable distance from their insertion (see Fig. 21). 

 In other species they are free, the whole way through. 

 Through the coherent horizontal disc the vascular 

 strands, springing from the node, pass out, entering the 

 free tips of the bracts, which turn vertically upwards 

 (Fig. 17). The structure of the bracts is much like 

 that of the small vegetative Calamitean leaves, described 

 above, but in the bracts, assimilating tissue appears to 

 have been absent, and fibrous elements, especially in 

 the apical portions, are strongly developed. 



The whorls of peltate sporangiophores alternate 

 with those of the sterile bracts, the number of the 

 former in each whorl being often about half that of 

 the latter. Thus in Calamostachys Binneyana there 

 are commonly six sporangiophores and about a dozen 

 bracts in their respective verticils (see Fig. 18), though 

 in other cases there may be eight sporangiophores, 

 while the number of bracts remains at about twelve. 

 The sporangiophores have the same peltate form which 

 is so familiar to us in Equisetum, but in Calamostachys 

 each peltate scale bears four sporangia only, attached 

 in a pendent position to the corners of the lamina 

 (Figs. 18 and 20), which has a somewhat square form 

 when seen in superficial view. A vascular bundle runs 

 to the base of each sporangium. In tangential sections 

 of the cone a group of four sporangia, diagonally 



