76 G. R. Wieland — Arnerican Fossil Cycads. 



proposed for the unbranched series of trunks from Black 

 Hawk including Cycadeoidea Jenneyana, ingens, aspera, for- 

 mosa, Stihcelli, excelsa, and rhombica ; so that in the end 

 the somewhat arbitrary use of macroscopic characters has 

 proven an indispensable convenience. For not only is there 

 rather more connectedness in the determination of the Ameri- 

 can series of species than in the nearly equal number of Euro- 

 pean forms, but these latter are on last analysis quite as 

 distinctly based on macroscopic diagnoses and even more des- 

 tined to revision. 



x * x x % * * 



The Cycadeoidea Marshiana trunk Xo. 3 of the Yale col- 

 lection, as at once appears in figure 1, bears many partl} T eroded 

 bract groups irregularly scattered all over the lateral armor 

 surface, plainly indicating the position of the deeply imbedded 

 fructifications. And as already noted, attention was first 

 directed to these rather inconspicuous flowers while searching 

 for younger fruits of C dacotensis, it being at the time over- 

 looked that such even when very young develop a huge pedun- 

 cular axis as in the examples shown in Plate XXXIX, fig. 1, 

 and on Plate XLI of the American Fossil Cycads. A partly 

 unexpected result was therefore obtained when the cutting of 

 sections from core No. II of the series here illustrated revealed 

 the presence of the quite full-sized, though apparently not 

 fully matured complete flower of figures 2 and 3. But unluck- 

 ily the first section, a longitudinal one, did not chance to tra- 

 verse the floral axis ; and it was not until several additional 

 sections were cut that the peripheral synangia were finally 

 observed and the position of the small flowers, no larger than a 

 Hxe centimeter length of a medium- sized lead pencil, accu- 

 rately located in the core. 



It was in consequence much hoped that in the course of the 

 further study of trunk Xo. 3, a second bud might be found 

 with a non-dehiscent disk in good conservation permitting 

 more perfect sectioning ; for the correct technique of course 

 requires two initial sections for the exact location of the first 

 or any other longitudinal section. And the study was carried 

 on until three additional cores were drilled out, these including 

 the very large one illustrated in figures 5 and 6, and alone con- 

 taining four separate strobili. But none of the new cores 

 yielded an additional disk, although no less than nine more 

 axes were found present, making a total of ten fruits studied 

 in the four cores removed from trunk 3. Only in a single 

 instance was even a trace of a disk found persistent ; in section 

 722, cut from the fourth and last core, one sees a considerable 

 mass of broken down disk tissue just above the cone as indi- 

 cated at S, figure 4. Evidently the disks at times slowly shriv- 



