80 



G. R. Wieland — American Fossil Cycads. 



The Flower of Cycadeoidea Marshiana. 

 I. Yale trunk No. 3. — Figures 2, 3, etc. 



The orientation of the series of sections of the sole complete 

 flower obtained from trunk 3 will at once be apparent on 

 inspection of the figures. &nd it will doubtless be granted 

 that the lesser difficulty of limitation to this single example is 

 more than compensated for by the resultant fixing of the period 

 of disk dehiscence at a given immature stage of ovulate growth, 

 even more accurately than in Cycadeoidea dacotensis. More- 

 over the series taken as a whole is nearly enough ideal to dis- 

 play the floral features with precision ; while the traversal of 

 transverse sections 717, 726 and 728 by trial saw-cuts and the 

 necessity of using approximately tandem sections for the longi- 

 tudinal view figure 2B has in nowise taken away from Mr. 

 Barkentin's figures. These have all that excellence lent alone 

 by the study of serial sections by both author and artist with 

 free use of photographs and joint verification of every detail. 



Fig. 3.4. 



Fig. 3 A. 



X/O. C.3(I[.A)S.7U 



Cycadeoidea Marshiana. Section 761, Yale trunk No. 3. x 10. 



Supplementary figure in continuation of transverse series shown in figure 

 3. The section traverses the microsporophylls at a point just beneath the 

 down-curving of the rachidal apices, the grouping of which plainly appears 

 at the center of the figure. 



In this Gamera lucid a drawing by the writer the ornate sculpturing of the 

 sporophylls, and especially the grouping and attachment of the synangia 

 plainly appear. 



The longitudinal section 714, figure 2B, stands at right angles to the base 

 line of the present section, and cross reference to the several figures shows 

 the location of all the sections. 



The silicification of the armor of trunk No. 3 does not 

 extend to the clear indication of the finer tissues of the 

 enclosed flowers, although all larger tissue zones and features 

 are clearly stained and outlined. So that in the bisporangiate 

 bud one clearly sees the main anatomical details, the peduncle 

 with its wood zones, the course at least of the bundles given 

 off, the bracts enveloped deeply in hairy ramentum, the out- 

 lines of the disk and component fronds with the position of 

 the disk and rachidal bundles (figure 3 A, section 761), the pin- 



