440 Solms-Laubach . — On the Fructification 
section is exactly longitudinal. The radicular end is slightly 
pointed ; the growing-point of the stem is visible in the best pre- 
parations as a short transverse line, above the middle of which 
the division between the two cotyledons comes to an end. In 
one seed, which I studied in the British Museum, and of which 
I possess a photograph through the kindness of Mr. A. Gepp 
(Plate XXVI, Fig. 6), the position of the growing-point is 
particularly prominent because local destruction of the tissue 
has produced a cavity directly above it filled with colourless 
stone. In all the embryos which I have seen the cotyledons 
occupied as a rule two-thirds, the stem-portion one-third, of 
the entire length. In some of them the tissue was in a good 
state of preservation (Plate XXVI, Fig. 5), especially in the 
cotyledons. This tissue is a parenchyma without intercellular 
spaces, consisting of brick-shaped cells arranged transversely 
to the surface of the cotyledons. In one case (see Plate 
XXV, Fig. 4, and Plate XXVI, Fig. 5) I could see that 
the tissue in the hypocotyl was formed of isodiametric poly- 
gonal cells, and was traversed by a central strand, the 
vascular bundle, from which a branch passed beneath the 
growing-point into each cotyledon ; but sections of such exact 
orientation are rare and accidental. If the longitudinal 
section, as sometimes happens, runs parallel to the bounding 
surface of the cotyledons, the embryo must necessarily appear 
as a homogeneous mass of tissue. In the much more 
common transverse or oblique sections 1 we see the circular, 
or in the latter case the more and more thoroughly ovoid, 
1 See Carruthers as cited above, pi. 59, f. 4. This preparation has supplied the 
photographs of the transverse section of the seed (see Plate XXVI, figs. 1-4), for 
which I am also indebted to Mr. Gepp’s kindness. But the section looks differ- 
ently now from what it did when the figure was drawn, because the whole of the 
middle portion has crumbled away and the marginal portion only, which contains 
the seeds, is still preserved. It was the custom at that time in England, and is 
still to some extent, not to keep the slices under cover-glasses, their thickness 
making it rather inconvenient to do so. But this custom leads ultimately to 
decomposition of the upper surface, and, when pyrites is present, to the destruction 
of the entire preparation. It is simply the oxydation of the pyrites which has 
caused the disintegration and crumbling of the central portions of the slice in 
question, and this would certainly have been avoided by covering it with a cover- 
glass. 
