168 Mr. J. Miers on the Biffnoniacese 



fe^ 



linear hilum, by which it is attached to the inner face of the 

 valves; upon this face, along the margins of each valve, there is 

 seen a broad longitudinal seminiferous zone, leaving the inter- 

 vening portion, which is as broad as the two zones united, co- 

 vered with a polished yellow endocarp : these seminiferous zones 

 are marked with a number of dark, rough, oblong cicatrices, 

 placed alternately in three or four parallel series, which corre- 

 spond with the hilar points of attachment of the seed, as in 

 Pithecoctenium. From this it will be seen that the attachment 

 of the seeds is strictly parietal — a feature hitherto novel in Big- 

 noniacea. This circumstance has probably led botanists to 

 suppose that it belonged to the CrescentiacecB, as it resembles 

 Crescentia in its hard shell, of similar shape and size ; but as it 

 is decidedly 3-valved and dehiscent, has a perfect and free dis- 

 sepiment, with a distinct replum, and quite devoid of pulp, it is 

 strictly Bignoniaceous and belongs to the tribe Bignoniea, dif- 

 fering in no respect except in its parietal placentation. It should 

 be observed, however, that the direction of the seeds and their 

 attachment by a marginal hilum, precisely in the same position, 

 occur in Pithecoctenium (see fig. 5, page 163) ; but in the latter 

 case the zonal bands of placentation remain fixed at a right angle 

 to the inflected margins of the free dissepiment, whereas in 

 this fruit they are attached to the valves : in all other respects 

 there is a perfect agreement between the two cases. The struc- 

 ture of the seed and the form of its integuments in this instance 

 are precisely as I have described them in Pithecoctenium, the 

 testa being in like manner bimarsupiate at the base of its discoid 

 cell by a short septum ; and in the recesses thus formed the 

 lower portions of the embryonary lobes are sheltered. In Pithe- 

 coctenium, the broad expanded part of the testa which forms the 

 pellucid winged margin around its discoidal portion is of the same 

 extent as in the fruit under consideration ; but it is filled to its ex- 

 treme edge by a thick deposit of cellular tissue between its faces, 

 so that it loses its transparent character, and becomes thick, hard^ 

 and coriaceous, as in the seeds of Heterophragma : the inner in- 

 teguments, which closely invest the embryo, are about half the 

 length and half the breadth of the testa. 



I shall presently recur to the genus Tanaecium of Swartz, 

 respecting which a strange degree of confusion has existed. 



[To be continued.] 



