CARBONIFEROUS LYCOPODS AKD SPHENOPHYLLS. 107 



John Rorrison at No. 3 Pit, Springhill, Crosshouse, Ayrshire, from 

 the major coal belonging to the Lower Coal Measures (No. 1573). 



This fragment shows a small portion of a Sigillarian cone which 

 has apparently been split longitudinally. The upper parts of the 

 bracts are imbedded in the matrix, and their basal extremities 

 only are exposed on the surface of the rock and show their upper 

 surface. 



The basal portions of the lower sporophylls are about 3 mm. 

 wide, and lying on their surface are numerous small, smooth 

 macrospores about 075 mm. in diameter. The upper sporophylls 

 have larger bases, measuring about G mm. across, and are in a 

 fine state of preservation. When the upper surface of their 

 exposed base is examined under the microscope it is found to be 

 distinctly granular. These granular roughnesses measure about 

 0'20 mm., and are covered by a thin cellular envelope, the size of 

 the cells forming this layer being such that from 3 to 4 cells 

 equal the size of the individual roughnesses.' 



On the exposed surface of some of the bases of these larger 

 upper sporophylls is a sub-rhomboidal mark with a central point, 

 and below it the indication of a semi-circular area. This may 

 represent the point of attachment of the sporophyll to the axis of 

 the cone, but of this I am not certain, as it might perhaps 

 represent the part where dehiscence took place. 



It is from the examination of this specimen that I have been 

 led to believe that the cones of Sigillaria are hetorosporous, for 

 on the lower sporophylls the macrospores are very clearly seen, 

 while the bases of the upper sporophylls are much larger and 

 distinctly different in size from the lower, and it seems difficult 

 to give any other explanation of their granular appearance than 

 by supposing it to have been caused by contained bodies, 

 presumably microspores. I do not regard this specimen as 

 determining conclusively the heterosporous condition of the cones 

 of Sigillaria, but it points strongly in that direction. 



The majority of Sigillaria appear to have had pedicellate cones, 

 as indicated by the scars on the stems, but in Sigillaria discophora, 

 Konig sp., and Sigillaria Taylori, Carr. sp., they were sessile, and 

 arranged in two opposite vertical rows. 



1 Kidston, Trans. Roy. Soc. Edin., Vol. XXXIX., Part i. (No. 5), PI. II., 

 figs. 1, la, and \h. 



