G. B. Wieland — American Fossil Cycads. 385 



more or less obliteration. The appearance of the fruits as 

 apparently mature on the trunk, and of the scars mentioned 

 above, are fairly well represented in figures 1 and 2, Plate VIII. 

 In all cases where the seeds are exposed the tips of the bracts 

 are necessarily more or less worn or broken away. 



The lateral, or proliferous, inflorescence here exhibited is 

 noteworthy. In this respect these specialized culminant fossil 

 types vary from all the higher existing forms which are sym- 

 podial, and partially agree with the genus Cycas. The latter 

 is the most primitive living form, and has its peduncles dis- 

 tributed between the petioles for some distance below the apex 

 of the trunk. Among the various species represented in the 

 Yale collection there are none showing the sympodial type and 

 but few flower-bearing examples which have no flowers on the 

 lower half of the trunk, though the male trunks incline to bear 

 the most of their flowers near the summit. 



Special Organs. — As stated above, these fruits are ovoid 

 bodies borne on short peduncles. The latter take their origin 

 on the trunk after the manner of the petioles and terminate in 

 an elongated receptacle. This bears laterally an involucre of 

 slender enveloping bracts, and terminates in a " parenchyma- 

 tous cushion," as termed by Carruthers. 3 The face of this 

 cushion, or secondary receptacle, is flatly convex and bears two 

 series of densely set organs, much modified according to their 

 central or more peripheral position. The first of these are the 

 seed-bearing stems, or essential organs, while the second are 

 merely interstitial and quite analogous to chaff. They are 

 termed " interseminal scales " by Lignier. 



The disposition of these parts is illustrated in the longitudi- 

 nal sections, figures 10 and 12, Plate IX, and in the correspond- 

 ing transverse sections, figures 9 and 11 of the same plate, as 

 well as in the several transverse sections on Plate X. 



In this arrangement of densely set seed-bearing stems and 

 surrounding scales borne on a fleshy bract-enveloped receptacle, 

 there is a certain simulation of the flowers of Composites. 



Histological Structure. 



The Parenchymatous Cushion. — This is composed of soft 

 parenchyma centrally, but becomes more dense peripherally. 

 Though no well-marked bundles have been noted, sparse and 

 irregularly branching strands of scalariform cells apparently 

 supply the seed stems. As there is usually a cleavage line, or 

 zone of imperfect preservation, just at their origin, this could 

 not be readily determined. The strands may scatter and end 

 in the cushion. They are illustrated by Carruthers in his 

 description of Bennettites Gibsonianus. 



