﻿270 AMERICAN FOSSIL CYCADS. 



Plate XXV. Cycadeoidean Ovulate Strobili in Longitudinal and 

 Transverse Section. 



Photograph I. — Cycadeoidea turrita (T. 76 + 375)- S. 349. X 5- Longitudinal section 

 through ovulate strobilus with rather short (young) seed pedicels. This strobilus is of 

 especial interest as the only fruit whatsoever borne on a large segment of a cylindrical trunk 

 with otherwise unbroken regularity of leaf-base spirals. Photograph 5, plate v, shows the 

 original trunk and position (0. S.) of the present strobilus. 



Photograph 2. — Cycadeoidea turrita. (T. 481). S. 179. X 5- Longitudinal section 

 through base of strobilus and receptacle, showing characteristic splitting off of woody mass 

 of seed pedicels and interseminal scales from the pithy receptacle or "cushion" beneath. 



Photograph 3. — C. turrita (T. 15). S. 74. X 4- Longitudinal section through strobilus. 

 s, a short-pedicelled seed ; i, a mass of interseminal scales or of aborted pedicels borne over 

 a considerable portion of the inner area of the receptacle, to the exclusion of fertile pedicels ; 

 p, receptacle; b, bract; d, dehiscent line (?), similar to that seen in photograph 2, plate xxo. 



Photograph 4.— C Wiclandi (T. 393). S. 103. X 4- Transverse section cutting por- 

 tion of strobilus with seeds evenly ranked as in No. 6, which is cut at right angles to the 

 present section from the same cone, whence two peripheral rows of seeds appear. The cone 

 from which this section was cut is shown as seated on the parent trunk in its natural posi- 

 tion at s, photograph 1, plate xxi. Transverse saw cut made in making the section likewise 

 further indicates the exact position in the cone. 



Photograph 5. — C. Wiclandi (T. 393). S. 394- X 3- Similar to the preceding, but 

 cutting through the lowermost seeds, whence but a single peripheral row of seeds appears. 

 For enlarged view of two adjacent seeds containing proembryos (/>), see plate xxx. 



Photograph 6.—C. IVielandi (T. 393). S. 108. X 12. Longitudinal section through 

 adjacent seeds. 



Plate XXVI. Cycadeoidea. Seed Pedicel System of Ovulate Cone. 



Photograph 1. — Cycadeoidea IVielandi (T. 393). S. 393. X 4- Transverse thin sec- 

 tion through two adjacent ovulate strobili; cut beneath the lowermost seeds and displaying 

 the series of enveloping bracts and several of the surrounding leaf-bases. (Cf. photographs 

 4 and S of the preceding plate, showing two sections cut at a higher level.) 



Photomicrograph 2. — Cycadeoidea IVielandi (T. 77). S. 7. X 32. A small area of 

 a section similar to the preceding, but from another cone, showing the transversely cut 

 series of seeds pedicels and surrounding interseminal scales. The ground tissue is not pre- 

 served in either the central bundle of the pedicels or interseminal scales ; whence the relations 

 between the pedicel and scale system appear with diagrammatic clearness. Inspection of 

 the figure at once discloses the fact that the wide envelope of cortical tissue forms the 

 outermost structure of the pedicels, and that the catenulate rows of small transversely cut 

 woody cells are double between appressed sterile scales and single next to the fertile pedicels, 

 and hence epidermal to the scales. (Cf. text-figures 59 and 61.) 



Plate XXVII. Cycadeoidea. Structure of the seed pedicels, 

 and interseminal scales. 



Photomicrographs 1-3. — C. IVielandi (T. 393). S. 103. (Cf. view of entire section, 

 plate xx v, figure 4.) 



1. Pedicels and interseminal scales with all structure preserved, cut transversely a cen- 

 timeter or less beneath the seed bases. Compare with the lower figure of plate xxvr, where 

 the bundle parenchyma has failed of preservation in both pedicels and scales. X 35- 



2. Transverse section of a single interseminal scale, with cortex of three adjacent seed 

 pedicels. X 225. But a single vascular bundle appears at the center of the scale and no 

 instance of a second bundle has been noted in any of the sections, although four or more 

 bundles are present in the basal scales of the cone Bennettites Morierei, as recently observed 

 by Lignier (86 a). 



