DESCRIPTION OF THE PLATES. 
is also external to the placentaxy expansion e, to which the seed is attached ; 6, 6, the two 
proper membranaceous tunics of the seed (testa and tegmen), which by their inflexion 
closely invest the albumen aU over its external surface, as well as upon its large hoUow 
central cavity ; c, the albumen with its large hollow central space ; d, part of the inflected 
portion of the testa, in form of a curved tubular channel in which the spiral vessels of the 
raphe are imbedded ; this raphigerous tube is in no way connected with the external crus- 
taceous arilloid shell, but is attached to the fungous expansion of the placenta, e, which 
partly fills the hollow central space of the seed ; in the fruit, the fungous expansion, e, is 
connected with the placenta through the hilar aperture of the external shell : / is the 
minute embryo, with the cotyledons directed to the chalaza and to the centre of the seed. 
Fig, 12, the embryo, much more magnified. 
Plate 29. — A. Details of Stteax officinale. 
Fig. 1, a flower expanded. Fig. 2, two of the petals. Fig. 3, the stamens : all nat. 
size. Fig. 4, a stamen seen sideways, in front, and from behind, showing two parallel 
cells separated by an interval, and dorsaUy attached by their entire length to the filament. 
Fig. 5, a transverse section across the anther : both magnified. Fig. 6, the pistil, with 
half of the calyx cut away, nat. size. Fig. 7, the stigma with a portion of the style, 
magnified. Fig. 8, longitudinal section of the ovary, with its unilocular space, and its free 
central placenta, to which the ovules are attached iu three series. Fig. 9, the same, with 
the ovules removed, showing the central placenta, and the three narrow rudimentary and 
incomplete dissepiments : both magnified. Fig. 10, a seed seen sideways, showing the 
basal and somewhat lateral hilum. Fig. 11, the same, seen from below, showing the hilum 
and the open aperture into the raphigerous channel, and the three longitudinal marks 
produced by the impression of the three incomplete dissepiments of the pericarpal covering. 
Fig. 12, the seed removed from its osseous testa last described ; all nat. size. Fig. 13, a 
longitudinal section of the osseous testa, with the hilar portion left to show the aperture 
into the short raphigerous tube imbedded in the base of the shell. Fig. 14, the same, cut 
across the hilum, to show the basal raphigerous channel, and the mode in which the 
vessels of the raphe become rapidly subdivided into an araneiform network of white spiral 
threads, which partly adhere to the inner surface of the osseous testa, and to the outer 
surface of the membranaceous integument that closely invests the albumen, as seen in 
fig. 15. Fig. 16, a longitudinal section of the albumen across the place of the hilum, 
showing the enclosed embryo lying across the hilum, with the cotyledons parallel to it. 
Fig. 17, a transverse section of the same, in a line parallel to the embryo, which is shown 
in its natural position : all magnified. 
B. Details of Stteax odoeatissimum. 
Fig. 1, a flower. Fig. 2, the corolla cut open, showing the position of the stamens. 
Fig. 3, imbricated mode of aestivation of the petals : all nat. size. Fig. 4, a stamen seen 
in different positions, showing the distinct parallel cells of the anther dorsaUy attached to 
the broad filament, magnified. Fig. 5, the pistil, with half of the calyx removed. Fig. 6, 
a fruit. Fig. 7, the same, seen from below : all nat. size. 
C. Details of Stteax Poeteeianum. 
Fig. 1, the calyx. Fig. 2, the coroUa cut open, showing the petals slightly attached at 
base by the attachment of the foot of the stamens : both nat. size. Fig. 3, diagram showing 
the imbricated mode of aestivation of petals. Fig. 4, four of the stamens, showing the manner 
of their agglutination to the petals, magnified. Fig. 5, pistil, vrith half of the calyx re- 
