M. J. Minter on the Structure of Nuphar lutea. 237 
centric ; at the bottom of the pit a bundle of woody fibres, broken 
off, but still somewhat projecting, hke the ligamentum teres of 
the human acetabulum ; the surface of the pit between this woody 
bundle and the ring-shaped scar is smooth, and presents nothing 
remarkable. As regards the nature of these elegant pit-like scars, 
by comparing all parts of the surface we soon perceive that they 
owe their origin to roots, which separate spontaneously ; this view 
is confirmed by tracing the course of the separation. Hven whilst 
the root is perfectly entire, the bark of the stem is raised from 
the surface of the latter, and gives rise to the above-mentioned 
limb. The concentric rmg on the inner surface of the pit is 
formed by the separation of the bark of the root from that of the 
stem, and the broken-off woody bundle found in the bottom of 
the pit was previously continuous with the central woody bundle 
of the root. 
Besides this interesting formation of sears from the spontaneous 
separation of roots, a phenomenon which I have never elsewhere 
observed, the solid contents of the cells of the highly developed 
pith excited particular interest. 
If we examine microscopically that portion of the stem most 
remote from the buds placed on the summit, we find that the 
contents of the cells do not assume any definite shape, but form 
a parenchymatous tissue filled with water or air. At the distance 
of 2—3 inches, however, and especially just beneath the buds on 
the summit, all the cells of the pith are filled with a solid sub- 
stance which has a definite form, is coloured blue on the addition 
of aqueous solution of iodine, and consequently agrees in proper- 
ties with starch. As regards the forms of the particles, some are 
simple, more or less rounded cells ; others are hemispherical, and 
formed of two grains lying in contact hke rolls; again, others 
form segments of circles, and derive their shape from the union 
of three double grains, and are arranged either in a linear or 
superficial manner : we also observe granules which are formed 
from the union of four, and finally perfect penta- and polyhedra. 
Whilst these forms agree most distinctly with those of the 
starch particles which I found and described in Gloriosa superba, 
their size forms also another point of similitude ; it cannot indeed 
be asserted that the Nuphar starch in general exhibits such 
large particles as the Gloriosa, but it most resembles it in the 
relative size of the separate granules ; in it the internal layers are 
as sharply outlined as in the Gloriosa starch, and thus afford a 
good substitute for the latter, which is so difficult to obtain. For 
this reason I recommend the Nuphar starch as an excellent ex- 
ample for those who have occasion to demonstrate microscopi- 
cally ; and also to those who may think it worth while to test my 
view of the centripetal formation of the starch granules, as I am 
