THE EVOLUTION OF PLANTS ' 2IS 



enia) have lateral seed-bearing cones (Fig. 95) ;^ in the 

 other genera the carpellate cones are terminal (Fig. 96) . 

 Various structural characters of Cycadeoidea are shown 

 in Figs. 92-100. 



In Cycadeoidea dacotensis the "flower," which in some 

 specimens was 5 inches long, was a strobilus, consisting of 

 a thick axis on the lower part of which were numerous 



Fig. 99. — Cycadeoidea ingens. Restoration of an expanded bispor- 

 angiate cone, or flower, in nearly longitudinal section. Restored from a 

 silicified fossil. (After Wieland.) 



bracts arranged in spirals. The bracts surrounded a 

 campanula of about 20 stamens. Each stamen was, in 

 reality, a pinnately compound sporophyll, about 4 inches 

 long, rolled in toward the center of the flower, and bear- 

 ing two rows of compound microsporangia (pollen-sacs) 

 on each leaflet. They thus closely resembled the sporo- 

 phyll of a fern. 



' The staminate cones of Zamia are lateral. 



