64:8 Wieland — American Fossil Cycads. 



(See American Fossil Cycads by the author, Vol. I, fig. 



80 b.) 



With these explanations the following measurements 

 may be intelligibly read : 



Greatest length of flower and peduncle. . 30 ± Millimeters 



Diameter of cone, disk, and bract husk 10 " 



Diameter of woody cylinder of peduncle 2 ' ' 



Diameter of peduncle 4-5 



Cone and disk length 10 " . 



Diameter of ovulate cone 5 



Greatest length of young seed stems .... 2 



Diameter of seed stems -2 



Disk thickness -3 " 



What light, if any, does a flower like that before us 

 throw on the nature of other ancient flowers, and on 

 the nature of seed or cone protecting envelopes ? In the 

 first place it may be adduced that some evidence has been 

 found for an irregular splitting of the Cycadeoidea disk 

 as it divides to form the apical dome. The flowers were 

 not always symmetrically divided into some given num- 

 ber of microsporophylls. Furthermore in the ovulate 

 flower of monoecious forms the disk aborts. Therefore 

 the first step backward to a pseudovarian envelope is 

 already visible. As already emphasized, 3 cone reduction 

 in some of the perfect Cycadeoid flowers ending in a sin- 

 gle erect seed must have occurred just as readily as in 

 Conifers. The Torreya type is here instructive; and 

 the staminate disk enclosing an aborted ovule in T umbo a 

 indicates that the ovule as well as the disk may abort. 

 Furthermore the Permo-Carboniferous Gnetopsis with 

 its somewhat imperfectly fused toothed cupule enclosing 

 a small group of three or four seeds, presents ancient 

 generalized features worth considering in connection 

 with aplosporophyllous gymnosperms. The toothed 

 form of the Cycadeoid dome suggests that the Gnetop- 

 sid pseudovarian covering may well have been derived 

 from a fertile staminate disk, or from more or less sym- 

 metrically fused leaves originally staminate. 4 And still 



3 American Fossil Cycads, Vol. I, page 244. 



4 Heer in the Flora Fossilis Arctica, Plate XV, figures as the "seed of 

 a Zamites (?)" from Kome, ? a fruit closely associated with Cycadeous 

 fronds, and exactly corresponding to the fruit of Williamsoniella, in both 

 form and size. In such fruits the frond tips envelope the central cone 

 like the hull of a small hickory nut, and are not decurved. They may be 

 bipartite. 



