CUPULIFER/E 



531 



"what larger, cuneate and trifid at the apex ; the seventh and 

 eighth are foliaceous but small. The ninth is much larger, 

 lanceolate-oblong, and distantly serrate. The tenth to the 

 thirteenth inclusive are elliptic-oblong, irregularly penni- 

 nerved and acutely serrate. The above characters of the 

 primary leaves vary according to the vigour of the seedling 

 and the conditions under which germination takes place. 

 The primary internodes have not the power of elongating, so 

 that when an acorn happens to be deeply buried with dead 

 leaves in a wood or plantation the primary leaves are arrested 

 in growth and scale-like, while those leaves or most of those 

 (probably never all) which reach the light become green and 

 foliaceous. The leaves of the adult tree 

 are mostly quite entire except in the 

 variety Q. I. serratifolia. 



The cotyledons of Q. pedunculata 

 are also subterranean. Several of the 

 primary leaves are reduced to scales as 

 in the last case and probably for the same 

 reason. The first green and foliaceous 

 leaf is obovate-oblong and shallowly 

 lobed at the top. Succeeding ones are ob- 

 ovate or obovate-oblong, and irregularly 

 lobed with alternate nerves running into 

 the lobes. The cotyledons of Corylus are 

 also subterranean. 



Alnus cordifolia, Ten. (fig. 666). 



Primary root tapering, flexuose, with a 

 few small lateral rootlets knotted with sessile 

 tubercles. 



Hypocotyl woody, erect, terete, finely 

 pubescent, brown, T75 cm. long. 



Cotyledons broadly oblong or oblong- 

 oval, obtuse, petiolate, glabrous, rather 

 fleshy, obscurely trinerved at the base, 

 pale green ; lamina 7'5 mm. long, 5 mm. wide ; petiole grooved 

 above, rounded and slightly pubescent on the back, 2 mm. long. 



Stem woody, erect, terete, pubescent, brown ; 1st internode 

 4' 25 mm. long ; 2nd 3 mm. ; 3rd 3'25 mm. 



Leaves simple, cauline, alternate, stipulate, petiolate, thinly 



FIG. 666. 



Alnus cordifolia. 



Nat. size. 



