ROOTS AND TUBERS. 
57 
the nerves are so ramified, not only amongst each other, hut 
also with the branch, that only one woody bundle goes through 
the branch in the middle. 
ROOTS AND TUBERS. 
A Note upon the Anatomy of the Roots of Ophrydeoe, by John 
Bindley, Tr. of the Linnean Society, vol. xviii. part iii. p. 423. 
The author says, that the tubers which form the roots of many 
African Ophrydece, on becoming dry, have the appearance of 
sacs, filled with small pebbles ; the surface is coarse grained, 
as if the epidermis was firmly contracted over hard substances. 
This may be seen particularly in the dry spindle-like roots of 
Disa multifida. On cutting across a fresh root of Satyrium 
pallidum, it will be seen distinctly whence this appearance 
arises. A great quantity of oval, tough, and solid nodules, 
clear as water, and frequently twenty times the size of the cells 
which surround them, are found in the tender parenchyma. 
These nodules may readily be separated from the cellular tissue 
in which they are situated, and they appear to be of an irre- 
gular polygonal shape, like polished stones of rock crystal. 
Their facettes are produced by the pressure of the cells of 
parenchyma between which they are situated. They are tough 
like horn, cannot be torn, crackle between the teeth like 
pieces of caoutchouc, may readily be cut even into slices, and 
then appear quite homogeneous ; they do not exhibit any 
layers either in a fresh or dried state, or when treated with 
chemical reagents. They are generally of the same size, but 
some are not larger than the ordinary cells of cellular tissue. 
The nodules are scarcely soluble in cold water, but swell upon 
being boiled, and are partially dissolved into a transparent 
jelly, having the appearance of glass. On exposing them to 
the air, they rapidly become dry, and of a dark brown colour. 
The diluted solution of iodine does not perceptibly act upon 
them, but the tincture of iodine gives them a claret colour, on 
being previously treated with caustic potash, or nitric, or sul- 
phuric acid. The diluted solution of iodine colours starch 
449 2 F 
