as distinguished from the Symplocacese. 139 



is thin and membranaceous, and often somewhat adherent to the 

 osseous celkile, but it is extracted without difficulty, and, when 

 dry, is of a dark colour, smooth, thin, and of a somewhat char- 

 taceous texture, with a very prominent, adhering, external, simple, 

 cord-like raphe, proceeding from the hilar point of its attachment, 

 and extending along its ventral face to its opposite chalazal ex- 

 tremity, in a line corresponding with the nourishing threads 

 before described, and facing the original axis of the placenta : 

 the inner integument is a delicate transparent membrane that 

 closely invests the albumen ; and at its extremity, opposite to 

 that of the hilum, it has a small well-marked chalaza, under the 

 form of a coloured transverse line ; at the opposite extremity or 

 radicular end, 1 have always found a distinct, dark-coloured, 

 free, adpressed thread, which is easily raised by a point ; it is a 

 suspensor : the albumen and embryo quite accord with the de- 

 scriptions of Gaertuer and DeCandolle. It may be remarked 

 that the radicular end, with its suspensor, is sometimes superior, 

 at other times inferior, owing to the reason before assigned. 



I will add a few words respecting the development of the en- 

 tire fruit. The calyx, in its young state, has eight prominent 

 external uervures, of which four are op])osite to the incom})lete 

 cells of the ovary, and terminate in the points of the teeth of the 

 bordei', the other four alternating with the calycine segments ; 

 these last, with the growth of the ovary, acquire a considerable 

 increment, producing, in Halesia tetraptera, four long, broad, 

 corticated wings, and in H. diptcra, only two opposite broad 

 wings, the two alternate ones being much narrower ; these wings, 

 in the ripe fmit, are thickened considerably towards the peri- 

 carp, and are filled with a soft pith, which extends in a thin 

 layer over the whole of the nut ; the latter is indehiscent, fusi- 

 form, sharply pointed at both ends, thick, and osseous, with 

 about eight deep grooves. It is justly remarked by DeCandolle, 

 that in the ovary, as well as in the fruit, the cells are placed 

 opposite to the wings, not alternate with them, as figured by 

 Gaertuer. 



From the above facts it is evident that, in order to compre- 

 hend the natm-e of the structure of the fruit in Halesio, it is 

 necessary to trace the progress of the growth of its ovary from 

 its eax-liest stages to the period of its ultimate development : we 

 thus see how by degrees each ovule is removed from its normal 

 basilar position, and apparently carried up towards the centre, 

 and is afterwards found in a parietal sac attached to the middle 

 of the wall that surrounds a large central vacant space in the 

 growing ovary ; but how this open sac extends itself into a com- 

 pletely closed cell, at fii-st membranaceous, and then hardened 



