﻿BISPORANGIATE AXES. 



'5 1 



on plate m. In several of the present series of sections preservation of the middle 

 region of the fronds forming the summit of the nnexpanded strobilus is, how- 

 ever, nearly complete. The space interior to the once-deflexed fronds is densely 

 packed with well-developed synangia borne on slender pinnules, which are folded 

 rankwise in the radial position in such a manner that it has been possible to carry 

 the grinding of the median longitudinal section 360 to such a plane that all the 

 fertile pinnules not only may clearly be seen attached to the rachial axis at regular 

 intervals from its base to near its tip, but are mostly cut throughout their entire 

 length, and alternate with rows of densely appressed synangia. But in this section 

 only a few rows of synangia are seen attached, the most of the alternating rows 

 being free, as clearly appears in photograph 2, plate xxxvi. 



Fig. 75. — Continued. 



c. S. 483. Cut 1 .5 centimeters beneath S. 482. In this transverse section two additional leaf bases are cut. or four in all, whileonly 



two rows — necessarily the lowermost — of the imbricating bracts appear. The peduncle is greatly increased in size, and its woody 

 cylinder clearly indicated, as well as the small bract-trace bundles which pass out through the peduncular cortex into the bracts, 

 just as the leaf-trace bundles pass from the xylem of the trunk into the frond bases. 



d. S. 484. Cut 1.5 centimeters beneath S. 483 and about a centimeter out from the insertion of the peduncle and leaf bases 



on the cortex. In this section only the leaf bases closely surround the broad, vertically compressed peduncle. The peduncular 

 medulla is large and the inclosing xylem zone only sends off a few lower and therefore outer bract traces. 



Again, in making longitudinal section 361 (fig. 72) it has been possible to 

 grind down to such a plane as to bring to view on the right side of the cone only 

 the successive rows of synangia ; while the rachial axis on both sides, as well as the 

 sporophylls and rows of synangia on the left side, present the same general appear- 

 ance as in the closely parallel preceding section, No. 360. 



The sporophylls or fertile pinnules, as attached to therachis, are not curved, but 

 simply folded in radially at full length. Those borne by the ascending and 

 incurved portion of the rachis droop more and more, while those of the deflexed part 

 at first droop slightly downward and outward, but as the summit is approached 

 change their direction and are more and more upwardly turned. Hence there is 

 such a gradation of pinnule position from the base to the summit of the rachis 



