84 



MORPHOLOGY OF GYMNOSPERMS 



however, will recognize the fact that this is negative testimony. In 

 a fully developed embryo the suspensor may have become scarcely 



Fig. 68 FiG 69 



Fig. 68. — Bennettites Morien: longitudinal section of seed; a, micropylar tube; 

 b, prismatic layer; c, pulpy tissue; d, "corpuscular" mass; e, interseminal scale; 

 /, embryo space; g, remains of nucellus; h, chalaza; i, tubular envelope; k, micro- 

 pylar canal; /, nucellar beak; m, pollen chamber; n, fibrous stratum; 0, basal expan- 

 sion of n; p, pedicel bundle. — After Wieland's reproduction (22) of Lignier's figure 

 (18). 



Fig. 69. — Cycadeoidea Wielandii: longitudinal section of seed; a, micropylar 

 tube; b, expanded summit of interseminal scale; c, slightly palisaded layer of heavy- 

 waUed cells, which forms the true external coat of the seed, but is covered in all the 

 basal region of the seed by the woody and tubular cells of the cuplike extension (k) 

 of the cortex of the seed pedicels; e, wall of nucellus ending below the chalaza in an 

 expanded cup-shaped base; /, a structureless zone or simply a space between e and 

 g; g, stringy remains of cells expanding into a cup below; h, chalaza; i, woody scalari- 

 form tissue; k, continuation of the heavy-walled tubular' cells forming the outer layer 

 of the seed pedicels, which overlaps the outer layer of the seed (c) and forms the cuplike 

 seed support or husk; I, central bundle of pedicel; m, remnant of aborted seed arid 

 micropylar tube at the center of summit of interseminal scale; X12 — Figure and 

 description after WiELAND f22i. 



