582 STUDIES IN FOSSIL BOTANY 



bracts on its upper part. The centre of the flower is 

 occupied by the ovuliferous receptacle, about 4 cm. in 

 height, terminating the peduncle, as in BcnnetUtes 

 Gibsonianus (cf. Fig. 203, A). In C. dacotensis, how- 

 ever, the form of the receptacle is much more acutely 

 conical, and the stage of development, in the present 

 case, is a far earlier one, minute immature ovules taking 

 the place of the ripe seeds of the specimens previously 

 described. 



The stalked ovules and interseminal scales here 

 form a layer only 1.5 mm. in height (see Fig. 207, 

 where this zone is better shown), whereas in the mature 

 seed-bearing condition these organs have grown to at 

 least ten times the length. We have, in fact, at the 

 stage now under consideration, to do with a flower, while 

 the fructification of Bennettites Gibsonianus, described 

 above, was already a fruit. The receptacle bears 

 ovules in its middle region ; the base and apex are 

 sterile, and clothed only with the barren interseminal 

 scales, which at the apex are prolonged into a tuft 

 (Fig. 207). The details of structure of the ovules at 

 this stage have not yet been published. 



Surrounding the ovuliferous cone, and enclosed by 

 the bracts, is the whorl of compound microsporophylls 

 which forms the most striking feature of the flower. 

 The microsporophylls, or stamens, are numerous, 

 numbering from eighteen to twenty in C. dacotensis, 

 and are ranged in a single verticil ; they are inserted 

 hypogynously, below the base of the gynaecium (see 

 Fig. 206), and their stalks are united to form a con- 

 tinuous sheath (the " disc " of Wieland), like the 

 monadelphous stamens of a Mallow (see diagrams, 



