42 BOTANICAL GAZETTE [JANUARY 
the node. It may be distinguished quite early, appearing as a 
papilla formed by rapidly growing hypodermal cells (fig. 3). 
This figure represents a median longitudinal section cut trans-— 
versely to the surface of the young frond. The epidermal cells 
divide as they are forced out, forming a temporary root sheath. 
This sheath may persist for some time ( figs. 4, 5, 6) but is 
finally broken and decays. 
Very early in the development of the root the layer of cells 
is seen (fig. 3, a) that develops into the root cap. This layer 
continues to thicken by additions from the meristem region 
below (fig. 3,6). The number of cells constituting this meri- 
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Fic. 6. Young roots, each showing tempo- 
rary epidermal sheath, root cap, and the main 
body of the root. @, meristem cell. X 760. 
stem region is unusually 
small (figs. 5, a, 6, a), in 
some cases consisting ap- 
parently of but one cell. 
The walls of these cells 
are drawn heavier than 
those of adjacent ones, 
simply to point them out. 
Miss Amelia McMinn (11) 
states definitely that this is 
an apical cell, and such 
may be true as to posi- 
tion, but probably not as to 
morphological character. 
I find no such break in 
the continuity of cells at 
the root tip as shown by 
Hegelmaier in f/. 10, figs. 
8, 9 of his Monograph. 
The root cap is at first united with the main body of the 
root (fig. 5), but back of the growing point it may be seen quite 
early to become free, and before the root has attained any (Oy 
siderable length the cap has become separated from a region 
opposite to the meristem down to the base of the root (figs. 4) 
6). In the older roots the cap is found still attached to the 
Sa cn A, 
