340 
AMERICAN JOURNAL OF BOTANY 
[Vol. io, 
cotyledon remains in the testa, and completely occupies the interior. The 
sheath tissues continue attached to the plumule as clasping lips upon the 
basal margin for a considerable time, in laboratory dishes until the daughter 
frond is well developed or even longer (but rain or other disturbances would 
act to separate these at an earlier stage). A seed, as it floats with the sheath 
tissues only protruding from the seed coats, resembles in size a normal 
specimen of Wolffla, but is of a different shade of green so as to be recognized 
quite readily in a mixture of the two. After protrusion the plumule ex¬ 
pands rapidly, but remains enclosed at its base by the clasping sheath walls, 
as well as held by the tissues connecting hypocotyl and plumule, at the 
insertion of the latter upon the embryo structure. Daughter fronds 
appear promptly, and, as these protrude from the pouch of the plumule, 
they often force off the still adhering cotylar sheath, though in some cases 
this is not accomplished until the second fronds appear. The base of the 
plumule, when nearly fully expanded but before the daughter frond is 
protruded, appears as shown in text figure I. In this figure, 5 indicates the 
point of attachment to the seed, B is the base of the daughter-frond stem, in¬ 
serted upon plumule tissue; L 2 , the daughter frond, with R, its root rudiment. 
The secondary fronds are shown at a and b, nearly or quite enclosed in 
pouches; and on the short stipe behind the base of L 2 may be noted a minute 
rudiment of an “axillary” bud, arising from the meristem of the plumule, 
as if from apical tissue. The rudiments, a and b, in the daughter frond arise 
in a similar manner, but appear to be differently situated through the 
thrusting forward of the region upon which they are inserted, by an elonga¬ 
tion of the stipe and the backward overgrowth of the frond pocket. 
Text Fig. i. Base of plumule, with daughter frond ( L 2 ) in place, root rudiment at R, 
paired rudiments of next fronds at a and b ; stipe of daughter frond inserted upon plumule 
at B\ former attachment to cotylar sheath at S. Young frond rudiment as axillary bud 
on side of stipe near B (axillary to L 2 ). On same scale as figure 7, Plate XXVIII. 
