46 BOTANICAL GAZETTE [JULY 
certain amount of elasticity of bundle occurs here, but nothing 
like that in C. Fendlert. The enormous amount of thick-walled 
parenchymatous storage tissues seems to have more effect in 
giving firmness to the internal structure than does turgor. The 
bundles have almost no supporting function, and are never well 
developed, appearing, in the widest part of a fair sized specimen, 
only 1 in thickness of xylem. The branches passing out to 
the tubercles or ridges divide through the tissues as in C. Fendlert. 
The absorptive root contains numerous small crystals in the 
rays, more in proportion than appear in the stem. The chief 
xylem element is the scalariform tracheid ; fiber tracheids also 
occur. In the anchoring root, as before, the proportions are 
reversed. The phloem is mainly composed of sieve tubes, but 
has a slight sclerenchymatous compressed sheath, a character 
which will be noted as fairly constant in both stem and root. 
through the majority of forms. 
CEREUS GIGANTEUS Engelm.—The epidermis and hypoderma 
are both without crystals, the latter being exceedingly thick, of 
twelve to fourteen layers of cells. The assimilative tissue is of 
the usual elongated cells, the filamentous arrangement of which 
is extremely well marked, to such a degree even that the fila- 
ments in a preparation can be separated easily. Chlorophyll 
extends deep into the tissue, and the elongated character of cell 
is found for nearly 20™™. The medullary tissue is thick-walled 
and pitted, containing starch in the immediate vicinity of the 
bundles. Mucilage, though present in quantity sufficient to 
hinder the staining of sections, is not very thick. There is, 
however, especially in the younger parts, a watery solution 
apparently identical with that seen in £. Wislizeni, but much 
stronger, causing the tissue upon exposure to turn almost 
immediately from white to pinkish, and then to a dark purple. 
In bundle formation, the method described for EZ. Wislizent 
above is carried to greater perfection. Here not only do the 
bundles join their xylem portions, but all those of a single rib 
are surrounded by one sheath, formed gradually. In a young 
stage it may be seen outside each separate bundle, later two or 
