﻿144 



REPRODUCTIVE STRUCTURES. 



CYCADEOIDEA DACOTENSIS. 



(T. 214. Figure 14, and Plate VI, Photograph 12.) 



The descriptions which follow are based primarily on serial sections cut from 

 two bisporangiate axes borne by Yale cycad No. 214, and a third likewise wonder- 

 fully preserved strobilus borne by a superb branching trunk of the same species in 

 the collection of the State Uni- 

 versity of Iowa. The latter 

 strobilus was cut in the fall of 

 1900, with the kind permis- 

 sion of Professor Thomas H. 

 Macbride, who originally col- 

 lected the specimen to which it 

 belongs. For the form and 

 characters of these strobili con- 

 sult plates xxxiv-xlv, where 

 the photographs of the full 

 series of thin sections cut from 

 them are shown. As clearly 

 seen iu the plates and comple- 

 mentary text-figures, a nearly 

 mature stage of staminate 

 growth is indicated in each 

 of these cones, structure and 

 preservation also being remark- 

 ably alike in all three. 



In Chapter VIII a brief 

 description of the fruit-bearing 

 habitus of trunk 214 is given, 

 in connection with a considera- 

 tion of various ovulate cones it 

 bears. Here, however, for the 

 purpose of limiting the present 

 topic, only the structures of the 

 remarkably preserved bisporan- 

 giate axes numbered 1 and in 

 are taken up. These flower buds 

 are almost identical in size and 

 most features of preservation, 

 and are illustrated by various 

 photographs of plates xxxiv- 

 xxxvn, aud the accompanying 

 text-figures. In addition, the 



Fig. 71. — Cycadeoidea dacotensis. Vertical median longitudinal sec- 

 tion of bisporangiate strobilus in the same stage of growth as shown 

 in figure 70. All of the peduncle, with the surrounding leaf bases 

 and bracts, are drawn in the natural size from section 515, shown 

 in photograph 4, Plate XXXIX. But as the strobilar portion of that 

 fructification is imperfectly preserved, the ovulate cone and micro- 

 sporophylls are drawn from several other sections of similar strobili. 



s, Once-deflexed microsporopbyll ; o, ovulate cone ; a, eroded outer border line of 

 armor and bracts, or trunk surface ; r, ramentum between outermost bracts and 

 adjacent leaf base : 1, leaf base ; c, cortex ; t, peduncle bundle trace. 



very fine pollen-bearing fruit of this same species from the State University of Iowa 

 collection just mentioned duplicates and confirms every structural detail, as illus- 



