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AMERICAN FOSSIL CVCADS. 



Plate III. Cycadcoidca ingcns (type). X 3- 

 Photograph of longitudinal section through the bisporangiate flower bud. 

 This is the fruit marked by an arrow near the summit of the trunk shown in plate i. 

 The upper line is the saw cut- of the transverse section shown in photograph i. plate in, the 

 lower that shown in photograph 2, plate 111. The photograph is from a polished surface — 

 not from a thin section— and fairly reproduces the 

 shades of light and grayish quartz colorations to be / ,^ ( r\ $T$~'%y"" ~""<4 



seen in the fossil itself. The subjoined figure, traced // J-'^V''^ M t?$& .$£k— R 



directly from the photograph, locates the mam fea- 

 tures of this wonderfully well-preserved bisporangiate 

 strobilus — historically the first to clearly indicate the 

 true nature of fructification in the Cycadeoide;e. 



A, one of the series of synangia borne by a middle pinnule of one of the 



once-decurved staminate fronds. 



B, ascending portion of the rachis of one of the staminate fronds. 



C, a Urge central cavity due to the non-preservation of most of the central 



ovulate cone, the unquestionable contour of which is shown in dotted 

 outline with interior palisaded lines to indicate the young seed zone, a 

 portion of which is at several points conserved. (The cavity is lined by 

 a quartz druse.) 



D, synangia. 



E, bract hairs. 



F, a subcylindrical area of broken-down tissue. 



G, small basal synangia. 



H, base or receptacular region of ovulate cone. 

 I, insertion of a bract. 

 K. the peduncle. 



Explanatory outline figure. Natural size. 



Enlarged view of thin section from summit of strobilus parallel to surface view shown in plate. 

 Photographed in transmitted light. 



