X] 



PALAEOSTACHYA. 



859 



The axis of the cone bears whorls of bracts at right angles 

 to the central column. Each whorl consists of about 30—40 



FiQ. 98. Diagrammatic longitudinal section of Palaeostachya vera, sp. nov. 

 S, S, S, sporangia; x, xylem; sp, sporangiophore. (After Williamson.) 



segments coherent basally into a disc of prosenchymatous and 

 parenchymatous tissue. The free linear bracts curve sharply 

 upwards from the periphery of the disc, approximately parallel 

 to the axis of the cone. From each of these sterile whorls 

 there are given off 16 — 20 long and slender obliquely-inclined 

 sporangiophores, sp, which arise from the upper surface of the 

 disc close to the axis. Each sporangiophore no doubt bore four 

 sporangia, 8, containing spores of one size, — about '075 mm. in 

 diameter. The specimens of Palaeostachya vera so far obtained 

 do not show the actual manner of attachment of the sporangia, 

 but more complete examples of other species of Palaeostachya^ 

 enable us to assume with certainty that the sporangiophores 

 terminated in a distal peltate expansion bearing four sporangia 

 on its inner face. 



1 E.g. Eenault (82), PI. xix. fig. 1 ; (96), PI. xxix. figs. 1 and 4. 



