108 
Osborne^ on the Wheat Plant. 
matter is seen to accumulate; in it are a great number of nuclei, 
enclosed in minute egg-shaped vesicles (fig. 8 Ti), each nucleus 
being situated at the lesser end of the oval space in which it 
is contained. External to this granular matter, certain hyaline, 
thread-like processes (fig. 8 i) are seen interlacing vrith each 
other, forming thus an irregular network. A vertical section 
of that portion of a root which is producing one of these 
lateral roots shows a small vascular bundle, anastomosing 
from the centre bundle of vascular fibre in the root itself. 
This is surrounded with concentric circles of small cells, 
disposed with the utmost regularity. The new vascular 
bundle, with its envelope of cellular textures, now protrudes 
a cone-shaped apex into the external accumulation of granular 
matter ; that matter, with its network and numerous vesicular 
bodies, becomes to this protruded cone what the free capsule 
or spongiole is to the main root. It speedily assumes the true 
capsular form. The small vesicles expand most rapidly; their 
outer walls become in contact the one with the other, and by 
this compression they are forced into that peculiar form 
which is ever characteristic of the inner cell-structure of a 
capsule. The outer network appears now to resolve itself 
into a certain predetermined form of structure ; it is seen in 
union with a plasm, highly elastic, and equally transparent ; 
this fills up spaces to which what appeared as mere threads 
are now the walls or septa ; and thus that peculiar external 
coat of cells I have already described as seen on the point of 
a root, comes into a visible existence (fig. 9) . Simultaneously 
with this assumption of their normal outline, are seen the 
nuclei so generally found in them. These cells, bedded in the 
plasm in which and of which they are formed, now partially 
subdivide, and the whole rootlet (fig. 11) thus obtains aU the 
outward form and internal structure of the parent root, to which 
it is connected — without by a common parenchyma, within by 
the vascular bundle with its cells, which has anastomosed from 
the parent root. The base cells of the capsules of the roots 
and rootlets are gradually brought into connection with the 
parenchyma. Perhaps it would be more proper to say that 
the parenchyma is formed by the gradual addition of the 
lower cells of the capsules, to former cell-texture of the same 
kind, which has become the epidermic covering of the root. 
I believe it will ever be found that there is a clear space of 
membrane or plasm between the base of the capsule and 
those of its cells which were last drawn in to be incorporated 
as part of the parenchyma. 
Exterior to the cellular parenchyma, I long suspected that 
there was a coating of some hyaline plasm investing the 
