334 ON SEEDLINGS 



presence of the radicle which has to be accommodated. The 

 apical emargination or fissure is due to the intrusion of the 

 testa at that point where the chalaza is situated, as explained 

 under Bignonia speciosa. Catalpa speciosa most nearly ap- 

 proaches to the above, inasmuch as the seed is oblate and 

 strongly winged at either end, but the wing is continuous 

 at the apex, though not very wide, and is also continuous at 

 the basq except for a deep notch at the hilum. It is deeply 

 fringed or lacerated at either end. The greatly widened seed 

 and its short longitudinal axis are due to the narrowness 

 of the long, slender, cylindrical fruit. The embryo is oblate 

 and mi/ch constricted in the middle, almost dividing the 

 cotyledons into two equal suborbicular portions. The radicle 

 occupies one notch. 



A good type of a seed with a continuous wing is furnished 

 by Pithecoctenium Aubletii. The thickened portion of the 

 testa containing the embryo is not central, and the really 

 membranous portion is absent at the linear or oblong hilum. 

 The embryo is oblate, deeply constricted in the middle with 

 open notches and an extremely short radicle. Oroxylum in- 

 dicum is another instance of a broadly winged seed, and the 

 wing is slightly but irregularly dentate at the margin. The 

 embryo differs from that of the last by having the lobes im- 

 bricated at the apical fissure, almost hiding the latter. The 

 radicle is deeply seated in the basal notch which is otherwise 

 open. The fruit of Bignonia speciosa is oblong, flattened and 

 densely covered with tubercular spines or emergences. The 

 seeds are arranged in two rows in each cell upon widely sepa- 

 rated placentas, and are much imbricated, the lower ones always 

 overlapping the upper. They are oblate and broadly winged ; 

 and the embryo is constricted in the middle with rather wide 

 notches. Bignonia insignis differs by having its cotyledons 

 fleshy, amalgamated in one piece, and subterranean even after 

 germination. The embryo, however, conforms in shape to the 

 other species in all general particulars. Pajanelia multijuga has 

 rather narrowly winged seeds. The embryo is deeply bifid at 

 the apex but hardly notched at the base, while the radicle is 

 inconspicuous. It is not central. This also occurs in Stereo- 

 spermum suaveolens, but the wing is broader at each side 



