1898 - 99 .] Edith Chick on Eicinus Communis. 
653 
from its junction with the root to the level at which the cotyledons 
arise. The first pair of leaves are opposite and decussate with the 
cotyledons ; the subsequent leaves are alternate. 
As in the following descriptions references will frequently be 
necessary to the plane passing through the junction of the hypocotyl 
and root, it seemed well to use a definite term to designate this. 
The term 1 collet ’ has been used by some writers * to mean 
the whole region in which the transition from root to stem structure 
(internal as well as external) takes place. Later writers f use the 
term to designate the geometrical plane passing through the region 
at which the piliferous layer of the root gives place to the 
epidermis of the hypocotyl. 
In Eicinus it is immediately below the ‘collet,’ using the word 
in this latter sense, that lateral roots also are given off ; so that in 
this case the term denotes a plane separating all the external stem 
characteristics from those of the root. 
The Primary Eoot. 
Gerard J states that the bundles of the root vary from four to 
eight, and that out of ten specimens examined five were tetrarch, 
two were pentarch, two had seven and one had eight xylems and 
phloems. However, in twenty-one specimens examined I found 
only one varying from the tetrarch type ; this one was clearly 
abnormal, and, since it presented several points of interest, will be 
described later. 
Hear the root tip the centre of the cylinder is occupied by the 
fused bases of the four xylem bundles. Approaching the collet 
this position is taken by the pith. 
Passing outwards the xylem and phloem are quite normal in 
their characters and call for no remark. 
The pericycle forms wedge-shaped masses, eight to nine cells 
deep from apex to base, opposite the protoxylems; and narrows 
down until it consists of one or sometimes two layers of cells to 
the outside of the phloem arc. 
* M. Clos, “ Du collet dans les plantes,” Ann. Sci. Nat. Bot ., 1849. 
+ Dangeard, “ Le Botaniste,” 1889, Yan Tieghem, Traite de Botanique. 
+ Annales des Sciences Naturelles Bot., 1881, 
