222 G. R. Wieland — American Fossil Cycads. 



The main interior structures of this specimen are indicated 

 in the diagrams figures 1 and 2, page 221, based respectively on 

 the photographs of sections shown in Plate III, and in Plate IY, 

 figure 1. 



Between this flower bud and the apex of the trunk, distant 

 15 cm, is a thickly-set mesh of stipulary chaff enveloping a 

 series of finely-preserved, just emergent young leaves, which 

 will be described later. 



As removed from the trunk for examination, the general 

 shape of the flower bud was subcylindrical, with a slightly 

 tapering base and a strongly tapering summit. The length, 

 including a considerable portion of the peduncle, was 73 mm, 

 the basal, middle, and apical diameters being 35, 45, and 25 

 mm, respectively. Laterally it was covered with a series of 

 imbricating involucral bracts, the summits of which had been 

 eroded away. One very noticeable point was the division of 

 the free summit into twelve subequal sectors by radiating 

 lines apparently due to differentiation of tissues. 



The upper portion of the peduncle, figure 1, k, is seen to be 

 traversed by a series of fibro-vascular bundles, many of which 

 pass off into the involucral bracts. The latter are covered by 

 a mat of fine hairs quite similar to those borne by the involu- 

 cral bracts of Bennettites.™ A number of much larger and 

 coarser hairs also arise directly from the peduncle, between the 

 bases of the bracts. The position of the receptacle is indicated 

 centrally by nearly clear quartz, lacking well-defined structure, 

 and peripherally by a shoulder-like offset bearing most of the 

 involucre of bracts. 



The basal sori, figure 1, </, are not fully developed, and are 

 irregularly distributed in pockets. Following this absence of 

 arrangement, there is a soral grouping into eleven planes, which 

 successively increase their angle to the floral axis until the 

 terminal series rises vertically. It should be noted, however, 

 that this arrangement is only apparent in longitudinal radial 

 sections, situated at regular intervals with reference to the 

 plan of the flower. In other sections, the sori are crowded 

 together without a traceable arrangement, and the grouping in 

 planes is obscured. 



Inside the fleshy spore-bearing portion of the flower, which 

 may for convenience be termed the soriferal axis, is a central 

 cavity of quite regular form, lined by a druse of quartz crystals, 

 figure 1, c, in places resting on a thin layer of chalcedony, which 

 in turn rests on the silicified tissue. 



Aty, figure 1, is shown an undetermined cylindrical body 

 which has its origin on the receptacle, and curves upward round 

 the base of the soriferal axis, passing half-way up its side. As 

 there are at least ten, if not twelve, of these bodies 'quite 



