364 KANSAS UNIVERSITY SCIENCE BULLETIN. 
Krameria canescens is a low shrub, which attains a height of 
about 50 cm. The hard, woody stems are usually much 
branched. The branches may spring from the primitive stem 
or the bases of other branches which have died down. (Fig. 2, 
plate I.) During seasons of excessive drouth the stems may 
be without leaves, but under favorable conditions they are pro- 
vided with small, narrow leaves. The specimens used for this 
investigation, collected in the rainy season of 1908, show the 
stem and branches well supplied with leaves. (Fig. 1, plate I.) 
Both young stems and leaves are covered by a dense coating of 
closely appressed trichomes. Many of the branches have been 
modified as spines, thus reducing the surface for evaporation. 
The root attains a very great length and thickness in compari- 
son to the low growth of the shrub. This condition corre- 
sponds well with the dry climate and scant water supply of the 
earth in its habitat. The thick main root produces many sec- 
ondary roots, which have but few branches. 
The resemblance of Krameria canescens to the South Ameri- 
can species of Kramevia, yielding the official drug, makes it 
worthy of a somewhat detailed investigation. 
A comparison of the tissues of Krameria canescens with 
those of the official South American species shows its close rela- 
tionship to the species found growing in the northern part of 
South America and on the adjacent islands. This relationship 
is also shown by the structure of the flowers in which Krameria 
canescens and those species confined to the northern parts or 
South America have four stamens and three fully developed 
petals, while the one species, Krameria triandra, growing 
farther south, has three stamens and two fully developed petals. 
THE STEM. 
The exceedingly hard, woody stem of Krameria canescens, 
although not presenting any anomalous structures, has several 
interesting characteristics. The young stems are protected by 
a cutinized epidermis, which apparently remains functional for 
a period of three to five yars, and is then replaced by cork. A 
primary cortex and pericycle, not sharply differentiated, sur- 
round the vascular bundles, which form a hollow cylinder en- 
closing the medulla. (Fig. 3, plate II.) 
The epidermis, consisting of a single layer of nearly isodia- 
metric cells, 24 microns in radial diameter, with a cuticle 3 
microns in thickness, is in no way unusual (e, fig. 3, plate II). 
