388 



G. R. Wieland — American Fossil Cycads. 



purpose of comparing a large number of the same and differ- 

 ent species, and determining how far the structures supple- 

 ment each other. Hence no detailed account of seed structure 

 will be now attempted, although the appended figures, which 

 in reality are but little diagrammatic, are introduced. 



Figure 1.— Cycadeoidea (Bennetiites) Morierie, Saporta $ ; longitudinal section of 

 seed. (After Lignier.) 



a, micropylar tube ; &, prismatic layer; c, pulpy tissue; d, corpuscular mass; 

 e, interseminal scales ; /, embryo space ; g. remains of nucellus ; h, chalaza ; i, 

 tubular layer (= xylem zone) ; Jc, micropylar canal ; I, nucellar beak; m, pollen 

 chamber; n, fibrous stratum; o, basal expansion of «; p, parenchyma of seed 

 stem. 



Figure 2. — G. Wielandi, "Ward ? ; longitudinal section of seed, x 12 



a, micropylar tube ; &, interseminal scale ; c, the same ; d, cotyledons ; e, 

 fibrous layer ending below the chalaza in an expanded base of scalariform tissue ; 

 /", a structureless zone ; g, stringy remains of cells lignified and slightly expanded 

 below ; h, chalaza ; i, woody scalariform tissue ; ft, prismatic outer layer of seed 

 ending in xylem zone ; I, parenchyma. 



General Considerations. 



Owing to the large number of male and female examples of 

 Cycadeoidea in the Yale collection, their proper correlation will 

 require considerable time. Nevertheless, several facts of im- 



