STERLING: KRAMERIA CANESCENS GRAY. 371 
may also be found in a few of the parenchyma cells of the pri- 
mary cortex and in the phloém and wood parenchyma. They 
vary in size from 4 to 18 microns (fig. 49, plate VIII). Although 
the root starch closely resembles that of the stem in form and 
structure, the grains are uniformly larger and more oblong in 
shape (fig. 48, plate VIII). They range in size from 10 to 40 
microns and are very abundant in the parenchyma of all parts 
of the bark, medullary rays, and wood. 
CRYSTALS. 
Crystals of calcium oxalate are present in all parts of the 
plant. They are monoclinic prisms, or rosette-aggregate in form, 
and vary in size from 2 to 40 microns in diameter. Aggregate 
crystals 10 to 30 microns in diameter are abundant in the 
leaf parenchyma, while the small monoclinic prisms, 2 to 10 
mm. in diameter, are relatively few in number (0, fig. 51, 
plate VIII). In the stem, rosette-aggregates occur commonly 
in the parenchyma of the primary cortex and medulla (a, figs. 
51 and 52, plate VIII), while in the phloém they are seldom 
found, but monoclinic prisms are very abundant (fig. 53, 
plate VIII). The stem crystals are slightly larger than those 
of the leaf, and in the root they are considerably larger than 
in any other part of the plant. In the parenchyma cells of the 
outer root bark large aggregate crystals are found in consider- 
able numbers, and in inner parenchyma, especially those cells 
adjacent to the bast fibers, are densely packed with monoclinic 
prisms (fig. 50, plate VIII). 
All parts of the plant are well supplied with tannin, and it is 
especially abundant in the bark of both roots and stems. Ex- 
cepting the conducting cells of the xylem and phloém, all parts 
of the plant are intensely colored, from a reddish brown in the 
outer cork to a yellowish red in the inner parenchyma of the 
bark. The color is very persistent, and in order to make a 
detailed study of the tissues it was necessary to decolorize the 
material. This could be accomplished only by long bleaching 
of leaves and root and stem sections in aqueous solution of 
potassium hydrate and chloral hydrate. 
