SAPINDACKE 353 



become circinately coiled with their tips in the centre of the 

 coil. 



Other species agreeing with this type are A. monspessula- 

 num, A. opulifolium, A. neapolitanum and A. obtusatum. The 

 embryo is sometimes more folded in large seeds of the same 

 species. 



A. macrophyllum may be given as another type. The 

 seed-vessel is rather tumid and densely covered with bristly 

 or spiny spreading hairs. The interior of the seed is fur- 

 nished with an irregularly conical outgrowth of the inner coat 

 from the region of the hilum, and although the embryo 

 originates in the same way as that of A. Pseudo-Platanus, its 

 growth is obstructed by the process above mentioned, around 

 which it coils, with the edges and not the backs of the cotyle- 

 dons to the placenta. The cotyledons are eircinately coiled or 

 imperfectly biplicate transversely. A. insigne behaves in the 

 same way, but the cotyledons are more decidedly twice folded 

 transversely, and the outgrowth from the region of the hilum 

 is much smaller. 



A third type is represented by A. pennsylvanicum. The 

 seed-vessel is inflated or gibbous on one side, and concave 

 on the other, the seed conforming to this peculiarity. The 

 embryo originates in the same way as that of A. Pseudo- 

 Platanus, but, owing to the thinness or flattening of the seed- 

 vessel and seed, the cotyledons during their development 

 become twisted round into a vertical position with their tips 

 close to the hilum. The cotyledons are generally flat, but 

 sometimes become folded at the tip. A. montanum, A. 

 tataricum, and A. hircanum agree with this type, but the 

 cotyledons generally become more or less undulated longi- 

 tudinally owing to the seed-vessel and seed being more deeply 

 concave. They are even sometimes longitudinally plicate and 

 more or less folded at the tip. 



A fourth type is seen in A. campestre. This agrees in 

 general particulars with A. pennsylvanicum ; but the embryo 

 is larger and undergoes a greater amount of longitudinal 

 and oblique folding, so that in transverse section a number of 

 folds of the cotyledons are cut through. The seed-vessel is 

 much compressed laterally, but not, however, concave on 



