; 1904] LEWIS: ANOMALOUS DICOTYLEDONS 131 
cotyledonar tube. ig. 8 represents a series of sections from an 
alternate sections were drawn. This series makes apparent the 
great increase in the length of the tube and the almost equal 
depth of the bifurcations. It seems that the bifurcations do not 
become of exactly the same depth at any time, as an examina- 
tion of a number of series from mature, embryos did not show 
by this figure. 
_ It is very necessary to use series of cross-sections in tracing 
this development. Median longitudinal sections at right angles 
from similar sections of a typical dicotyledon. The ring of tissue 
and its two divisions increase greatly in length. There does not 
seem to be a localization of growth in the lobes here, as described 
for Nelumbo, but the ring itself grows at about the same rate as 
its two lobes. A narrow opening extends down to the growing 
point of the stem. The opening is conical just above the plumule, 
but for most of its length the walls of the tube are ‘in contact. 
The hypocoty] is short, and the plumule is but little developed 
_ inthe mature embryo. The growing point of the stem shows 
simply a slight protuberance into the conical opening at the base 
of the cotyledonar tube. The cells of this mound of tissue 
are slightly different in size and staining properties from those 
around them (jg. 73). 
The conducting tissue begins to develop as a central strand 
of narrow elongated cells, which extends almost to the plumule, 
where it divides, one division going to each of the cotyledons. 
The form of the mature embryo is shown by fg. 74, which is a 
: diagram to represent a median longitudinal section of a mature 
embryo. The figure was constructed from micrometer measure- 
“ments of a series of cross-sections of known thickness. This 
was found more satisfactory than making a drawing from a longi- 
_tudinal section, because in the latter it is impossible to distinguish 
the place where the cotyledonar tube leaves off and the opening 
between the two lobes begins. 
RA Eee ee res 
phen ace {015s SS aes 
