THE SEEDS OF GYMNOSPERMS. 



439 



the cone; in the Cypi'ess and other Cupressinea;, on the otlier liaud, toivdrth the 

 free margin of the scale (figs. 337 ^■*'^), and awa^- from the axis of the cone. 



In several species, as in the Stone Pine {Pinna Pinea) and the Arolla Pine 

 (Pimcs Cembra), the seed-coat attains a thickness of li to 2 millimetres, so that 

 the seed resembles a nut in appearance. Both these species, indeed, serve as an 



article of diet, being eaten like nuts. The seeds of Pines and Fir-trees are provided 

 with a one-sided wing (cf. figs. 335 ^■*'5) which plays an important part in their 

 dispersal by wind. In the Maidenhair Tree {G'lngko biloba) the integument of the 

 seed becomes succulent and coloured a bright orange, so that the seed in a way 

 resembles a drupe {cf. fig. 337"). In Cycas revoluta, also, the integument becomes 

 red and fleshy {cf. fig. 208 ', p. 74) 



