XLIII] 



MOKPHOLOGY OF CONES 



113 



The cone-scales of some species, e.g. A. Cookii, A. excelsa (fig. 

 683, A, D) are flat and laterally winged, while in A. brasiliensis 

 the thick distal ends closely resemble those of the seed-scales of 

 some Pines: the cone- scale of A. imbricata is larger and deeper a 

 and that of A. Bidivillii broad and woody (fig. 683, B, C). In 

 Pinus, with cones reaching a length of 2 feet, the mature scales 

 are apparently simple like those of the Araucarineae : the distal 

 end is broad and rounded (P. silvestris) with a central umbo or r 





FIG. 682. A, Agathis Moorei, cone-scales; s, scar of seed. B, Agathis loranthifolia, 

 section of ovule showing integument, nucellus, and megaspore with three 

 archegonia, also part of the cone-scale with a projection close to the base of 

 the ovule. (After Seward and Ford.) 



as in P. Coulteri, the umbo is prolonged as a strong recurved spine, 

 while in P. excelsa (fig. 704) and P. Cembra the scales are flatter 

 like those of Picea. In the young Pine cone each scale is clearly 

 a double structure consisting of a lower portion, the bract or 

 carpellary scale, and an upper portion, the ovuliferous scale, 

 bearing two ovules. In the course of development the seminiferous 

 scale alone increases in size, and the bract-scale is hardly visible 

 in the ripe cone or is represented by a small remnant. In Abies, 

 Larix, Pseudotsuga the dual nature of the scales is obvious at 

 s. iv 8 



