﻿282 AMERICAN FOSSIL CYCADS. 



bract hairs. (Cf. the fruit marked O. S. in natural position on the trunk shown on plate v, 

 photograph 2. Also see counterpart, figure 10, plate xlvii. ) 



Figure 2. — Similar to the preceding, hut showing the receptacle at its basal and most 

 constricted point. 



Figures 3 and 7. — These orbicular leafy bodies have usually been considered as apical, 

 and explaining the manner in which the so-called "pyriform axis" of Williamson ter- 

 minated. The form of this axis being also accounted for by the position of the parts of the 

 unexpanded bisporangiate strobilus, these orbicular growths may perchance represent: (a) 

 A terminal leafy growth of the ovulate strobilus as supposed by Saporta and Lignier ; (b) 

 a funnel-form calyx of either a hi- or simply macrosporangiate strobilus; or, (c) as is 

 quite likely, as an Alphlebia-like leaf of some accompanying plant. See legend, 5 and 6. 



Figure 4. — A cast similar to that shown in figure 2. but with the bracts completer 

 and suggesting the general size and outline of the ovulate cone. Globular receptacle not 

 conserved. (Cf. figure I.) — Specimen 2402, collection of Paris Museum. 



4«. — Surface details from sterile region at base of preceding cone. 



Figures 5 and 6. — Respectively the prepared cast and original natural mold of a stro- 

 bilus with a conical instead of globular shaped receptacle, which in the cast appears to ter- 

 minate as a pyriform axis. A possible explanation of the salver-shaped summit is that it is 

 not a true organic continuation of the conical ovulate receptacle, bearing sterile scales below 

 with the ovulate region mostly split away, but a cast of the central funnel-form depression 

 at the summit of an unexpanded bisporangiate strobilus, the lateral groovings simply being 

 the imprints of decurved rachides of the microsporophylls. Compare with various text- 

 figures in Chapter VII. showing the summits of unexpanded bisporangiate strobili. Some 

 central cones may have terminated in a spreading silky or scaly mass. 



Figure 7. — See legend of figure 3. 



Plate XLVII. Ovulate Strobili of Cycadeoideae. From Jurassic of England 

 and France, as figured by Saporta. Plantes Jttrassiques, vol. iv, atlas ( 125). 



Figures 1-4. — Beiinettilcs Morierei Saporta et Marion. Partially bract-covered ovulate 

 strobilus with microscopic structure preserved in iron carbonate. From the Middle Ox- 

 fordian Jurassic of Vaches Noire (between Villers sur Mer and AubervilleL Calvados, 

 Normandy. The type specimen is the only one known and is now in the collections of the 

 University of Caen. It has been made the subject of elaborate memoirs by Lignier (82, 85). 



1. Strobilus, natural size. 



in. Enlarged view of surface, showing the interlocking system of pericarp rosettes 

 formed by the nail-head-like termini of the interseminal scales surrounding the micropylar 

 tubes. The strobilus is generically related to some of the Black Hills forms. 



2, 3, and 4. Structural details of cone near summit of seed stems as revealed by the 

 splitting away of the outer portion of the cone. (2) Adjacent seeds borne apically on their 

 pedicels. (3) Ends of sterile sporophylls or interseminal scales and adjacent seeds. (4) 

 'I he same as 3, but near the lowermost seeds. Enlarged about four times. 



Figures 5-8. — Williamsonia Bucklandi Saporta. From Lower Oolite of Charmouth. 

 Dorsetshire, England. Collection of the Museum of Oxford. Figures 5, 50, 6, 6(7, and 8 

 originally from Buckland (18). 



5. An entire fruit divested of its enveloping bracts and showing the rosette-marked 

 epicarp made up of the interlocking hexagonal series of five to six sterile scales surround- 

 ing each seed. X 0.8. 



5a. Surface view of same enlarged. 



6. Seed slightly reduced. X 0.8. 

 6d. Seed enlarged four times. 



7. Portion of surface of ovulate strobilus shown in figure 5, enlarged to show details 

 of the pericarp rosettes of interseminal scales and relation to surrounding stigmatic openings. 



8. Same as preceding, further enlarged. Compare these figures with the photographs 

 of similar features of the Black Hills specimens, plate .win, and with text figure 57. 



