SAPINDACE^E 363 



Embryo originating in the apical, neck-like, curved portion of 

 the seed ; cotyledons ascending with their backs to the placenta 

 as in A. Pseudo-Platanus, till they reach the thickening and en- 

 larging process of the inner seed-coat, round which they twist 

 across the cavity of the seed with their edges to the placenta, as do 

 those of A. insigne, with their broad plane in consequence at right 

 angles to the placenta and conduplicate as in A. Pseudo-Platanus ; 

 radicle rather long, terete, bluntly pointed, inferior, and slightly 

 descending or nearly horizontal. 



Acer insigne, Boiss. et Buhse. 



The two samaras are often or always of unequal size, owing to 

 the non-development of the ovules in one of the cells ; wings 

 ascending or suberect, obliquely or half obovate, rounded at the 

 apex, reticulate, slightly pubescent or nearly glabrous ; seed-vessel 

 tumid, ovoid in outline. 



Seed slightly ascending, ovoid, obtuse, somewhat flattened late- 

 rally from the base towards the end distant from the hilum, con- 

 forming to the cavity of the fruit ; tegmen thickened in proximity 

 to the hilum and chalaza, but the outgrowth much smaller than in 

 A. macrophyllum. 



Embryo behaving in the same way as in A. macrophyllum, but 

 the cotyledons are more decidedly transversely biplicate. 



Acer pennsylvanicum, L. 



Fruit. The portion of the fruit containing the seed is rather 

 inflated or gibbous on one side and concave on the other ; this con- 

 cavity sometimes occurs on the same side of both halves of the 

 fruit, or on alternate sides of them. 



Seed broadly oblong in outline, more or less compressed laterally 

 but conforming to the cavity of the ovary and therefore concave 

 towards its indentation and convex to its gibbous side ; seed-coat 

 double ; hilum on the basal end of the seed. 



Embryo large, filling the cavity of the seed ; cotyledons straight 

 and plane or nearly so, but often folded back at the tip ; concave 

 in conformity with the fruit and seed ; radicle about equal to the 

 seed in length, terete, straight, or curved at its base only, the fold 

 being chiefly in the base of the cotyledons. 



A. tataricum conforms to the same type, but the cotyledons are 

 thrown into one or two folds, owing to the greater concavity of the 



A. hircanum also agrees, but the seed being considerably flattened 



