54 Sante BOTANICAL GAZETTE [JANUARY 
and delicate in structure. The hairy calyx consists of a tube and 
5 teeth-like lobes of about the same length as the tube, at the base 
of which is inserted the violet-colored corolla. The 1o stamens 
are combined in two sets; the ovary is one-celled with several 
ovules. At maturity the brown pods (fig. 1, ZV) are coiled 2-4 
times in close spirals, the diameter of the coil being about 4 mm. 
. The greenish-brown seeds (fig. 1, 7/7), up to 3 mm. in length, are 
somewhat kidney-shaped. 
Many varieties of alfalfa, less widely grown, vary in flower 
color, through blue, white, and green, to yellow, and in number of 
pod coils, seeds, and leaflets. 
-HISTOLOGY 
Stem (fig. 2).—The epidermal cells (ep) are several times longer 
than broad and arranged end to end in longitudinal rows inter- 
rupted frequently by stomata 
and their accompanying cells. 
The outer and inner walls are 
slightly thickened, the former 
having a cuticle with delicate 
striations evident in cleared 
preparations. 
Bast.—Several layers of 
. simple thin-walled chlorophyll- 
hot 2. fae aie cement = in bearing parenchyma cells, inter- 
Pveodber 5 Pe mciepestt ie ae rupted occasionally, especially 
vessels; Xx60 at the angles of the stem, by 
masses of collenchyma, form the 
outer tissues. Underlying this is a single layer of thin-walled 
crystal-bearing cells inclosing a zone of bast fiber bundles, each 
bundle being wedge-shaped in cross section. The individual fibers 
(f*) are greatly elongated and have walls so strongly thickened 
that the lumen is often but a mere line. 
Phloem.—This consists of a characterless mass of —— 
cambium cells and sieve tubes. 
Xylem.—The most evident elements of this woody tissue are the 
pitted (ta) and spiral (sp) vessels and the pitted wood fibers (/?)- 
