AND PECULIAR FORM OF THE EMBRYO IN THE CLUSIACEÆ. 251 
various attributes have been assigned. This determination is fortunately assisted by the 
drawings of Dr.Roxburgh,whose details, always accurately observed, are copied byDr. Wight 
in his ‘ Icones,” where in pl. 192. fig. 12 & 13, is shown a seed of Xanthochymus dulcis, 
in a state of germination, together with a longitudinal section of the same: here is 
depicted precisely the same linear process (the neorhiza), which is throwing out a root 
from the basal speck I have described, while the apical nipple of this same process has 
simultaneously become extended considerably, carrying upward with it the leaflets of the 
growing plumule: from the lower part of the neck thus protruded, and beneath the two 
lower scales which I have designated as the cotyledons, a second rootlet is seen to sprout, 
tending first horizontally and then downwards. We have here unquestionable proof that 
the process in question is what I have called neorhiza ; for were it the embryo imbedded in 
albumen, as Gærtner affirms, it would not throw out descending shoots at the upper por- 
tion as well as the base; nor would the same result follow if it were the radicle, according 
to the view of Dr. Graham. The fact is certainly fatal to the conclusions of Choisy, 
Cambessèdes, and other modern botanists, that the great mass of the nucleus consists of 
' two confluent cotyledons, and that the mammæform apex seen in the seed of the Clusiee 
is its radicle, even if this opinion had not been disproved by the structural appearances 
which I have already described, and which are still further confirmed by a more minute 
examination of its internal organization. __ | 
On placing a thin transverse slice of a seed of Lipophyllum (Clusia, Camb.) under the 
microscope, it will be seen to be of a reticulated texture, and composed of a number of 
small hexagonal cells filled with yellowish grumous viscid matter, except in the centre, 
across the line of the neorhiza, where the cells cease to be distinguishable: close to the 
periphery, and corresponding with the external striæ which I have described (p. 246), a 
circle of about fifty very conspicuous ducts is observed, each duct having a diameter 
three times” that of the reticulated cells: they are separated from each other by one or 
two rows of the same kind of cells that fill the main area, the circumference of the nucleus 
being formed of a very thin epidermis lined with parenchyma. On examining another 
slice of the same seed, cut in a vertical direction parallel with the axis, a somewhat 
different appearance is manifested; the cells no longer seem reticulated, but form regular 
longitudinal channels, interrupted by transverse septa placed at distances nearly equal to 
their diameter, bearing the semblance of articulated tubes or muriform tissue ; they cease 
-to appear along the line I have designated as the neorhiza: the large ducts near the 
` ha 
i i llow tubes with simply striated surfaces, and are filled wi 
margin are entire and hollow ply ae 
ellow secretion of a more fluid nature than that of the cells, i i 
te The neorhizal portion appears formed of longitudinal and exceedingly minute 
lines, exhibiting a uniformly striated opake and whitish texture. I have sone cm 
the seeds of the genus Quapoya, a structure exactly similar to that just ie = 
except that in addition to the external row, a few similar longitudinal ducts wi 
he main area. M. Cambessèdes, in his figure of 
ellow fluid a interspersed within t 
liste rian loi referred to, has depicted on the outer surface of the nucleus the same 
iris, b i i ‘in the text. 
external striæ, but he makes no allusion to the circumstance in 
It is requisite to offer some observations upon the nature of the external covering of 
2L 
VOL. XXI. 
