44 BOTANICAL. GAZETTE [JULY 
The absorptive root, therefore, will be the only one taken under 
consideration in discussing the remaining forms, except in one 
or two special cases. The difference between the two is hardly 
as well marked in Cereus Fendleri as in Opuntia fulgida, to be 
mentioned later. 
Ecurnocacrus WisiizEnt Engelm.—The epidermis and hypo- 
derma are without crystals, the latter of six or seven layers of 
cells. The assimilative tissue is compact, with cells much 
elongated perpendicular to the surface, even in the sinuses 
between the ridges. The young parts do not develop chloro- 
phyll in the sinuses until the ridges of tubercles, at first close- 
pressed together; become separated. The chlorophyll in this 
form is confined to a definite rind of palisade-like cells, which 
on the inside changes somewhat abruptly to a colorless paren- 
chyma, rather thick-walled and fitted with a splendid system of 
pits and openings. Within this tissue are occasional crystals. 
Mucilage does not seem to be abundant in this species, but its 
place is taken by a watery solution, especially prominent in 
parts still growing, which upon long exposure to the air causes 
the tissue to assume a pinkish tinge. The medullary tissue 
about the bundles contains a fairly large quantity of starch, 
greatest in amount and widest in distribution in the young 
portions. 
The bundles, as seen in cross section in a young stage, are 
not in a perfect circle, but rather in a zigzag line (fig. 6, dia- 
gram), with alternate points and depressions. There seems to 
be no branching or secondary medullary ray formation, and but 
little increase in the width of the original bundles. The zigzag 
line does not appear to be entirely the result of bundles passing 
out of the tubercles, for nearly all of the bundles in section 
appear to be cut directly across when all are cut in the same 
plane. They anastomose to a considerable extent, and, taking 
as centers the bundle at the base of each inner depression, join 
together with it to form a complex wood structure. The direc- 
tion of growth of the side bundles is slightly inclined toward 
the central one, bringing the xylem of the whole group into 
