﻿IJISPORANGIATE AXES. I 6 







The more or less elialeedonized condition of these fruits makes their study diffi- 

 cult in thin sections, although the general features are often outlined with remark- 

 able clearness on polished surfaces, as is explained and illustrated at length in the 

 legends and photographs of plates i to iv. The bisporangiate strobili of C. daco- 

 tensis and C. ingens were the first to be discovered and described in the Cycadeoidea;. 



CYCADEOIDEA PAYNEI. 



It is of more than usual interest that a single bisporangiate strobilus is borne 

 by the cvcadeoideau trunk No. 434; for this, specimen clearly belongs to the closely 

 related group of species which includes Cycadeoidea C'o/ei, C. Paynei, and C. Wie- 

 landi, with Bennettites Gibsonianus and B. Morierei. Although the preservation of 

 the uiicrosporophylls of this strobilus is not so good as that of the pollen-bearing stro- 

 bili described above, in the light of the facts already learned all the essential features 

 may be determined. And it is fortunate that this should be so; for otherwise we 

 should only be able to infer, from the characters of young fruits and the strobili 

 of other species, the nature of the staminate fructifications accompanying Ben- 

 itettiles Gibsonianus and B. Morierei and the American forms so closely related to 

 these species. Doubtless, however, other and better examples may be found, the 

 present strobilus having been noted only by accidental good fortune when searching 

 for young fruits. The surface characters did not betray the fact that a well-advanced 

 bisporangiate axis was present, and this was only learned after sawing through 

 the axis, as removed, for study. As cut in longitudinal section and represented 

 in plate xliii, photograph 7, the ovulate cone is seen to be quite large, having 

 reached a stage of growth that very clearly indicates its functional character. 

 Although not preserved entire, the central ovulate cone is fairly well outlined, the 

 convex receptacle fortunately being complete and of the characteristic shortened 

 form seen in Bennettites Gibsonianus and allied species. Resting on the some- 

 what crushed summits of the seed pedicels there is a mass of broken-down tissue, 

 among which are scattered the remnants of wilted sporophylls and a number of 

 fairly well preserved synaugia containing pollen and of the same general type as 

 those of C. dacotensis and C. ingens. Also at the base of the ovulate cone the rem- 

 nants of the staminate disk may be clearly made out, although presenting a stringy 

 appearance, as if wilted about the time of fossilization. From these meager details 

 it may only be inferred that the disk was not composed of as many fronds as in C. 

 dacotensis, and that the sporophylls were fewer in number and bore fewer synaugia, 

 the latter being of much the same size as in that form. 



The question of the position and general character of staminate fructification 

 in the Cycadeoidea; was of course settled by the writer's discovery of the male 

 inflorescence of Cycadeoidea ingens. But the present form leaves no further doubt 

 that many or quite all the ovulate fruits of the older types like Bennettites Gib- 

 sonianus and B. Morierei, and likewise all of the closely related Black Hills species, 

 were also bisporangiate and mostly bisexual. It may be emphasized that even 

 were the present bisporangiate fruit an isolated one, its form and structure would 

 at once enable one to recognize its relationship to the ovulate cones so plentifully 

 borne by trunks 77, 131, and 393, as described in Chapter VI. The structure of the 



