Das BULLETIN 692, U. S. DEPARTMENT OF AGRICULTURE. 
greatly in seed of certain different kinds. The base of the seed has 
a collarlike thickening, the callus, which sometimes bears a few 
bristlelike white hairs. The apex of the seed is pointed and three 
angled or four angled, depending upon the number of veins at the 
apex of the lemma. 
The lemma has at least three evident longitudinal veins, one near 
each margin, the marginal veins, and one in its center, the keel vein 
(fig. 3, 1). These veins produce the 3-angled form of the apex 
of the lemma. Often the keel vein does not develop to the apex of 
the lemma, and it sometimes develops into a bristle, or awn, projecting ~ 
from the keel of the lemma (fig.3, 4). In either event two additional 
veins, the intermediate veins, appear between the keel and marginal 
veins. The intermediate and marginal veins then give the apex of 
the lemma a 4-angled form. The lemma is thin and usually 
translucent at the apex, becoming thicker and opaque toward the 
base. The translucent portion of the lemma gives the seed of some 
species a silvery white appearance. 
The palet has two longitudinal veims if sufficiently well develo 
(fig. 3, 2 and 3). Itis very thin, often translucent and showing the 
darker gram beneath, sometimes transparent and obscure. It 
varies in size and texture and im its tendency to be free from or 
adherent to the grain. 
The grain usually is reddish brown, oblong in outline, and finely 
wrinkled at maturity. The interior, or endosperm, may be dry and 
somewhat resistant to pressure on crushing, or it may be semifluid 
and soft when crushed, depending on the species of the seed. 
DISTINGUISHING CHARACTERS. 
The distinguishing characters of the hulled seeds of redtop and 
the other commercial bent grasses appear in the comparative size and 
form of the seed, the texture and surface markings of the lemma, the 
character of the awn, the length of the palet compared with the length 
of the lemma and of the grain, its texture and degree of adhesion to 
or its freedom from the grain, the size and consistency of the gram, 
the associated weed seeds and other seeds, and the character of the 
chaff, if present. 
In practical seed analysis, small bulk samples of commercial seed 
of redtop, Rhode Island bent, colonial bent, and South German 
mixed bent can be distinguished one from another. The velvet- 
bent seed in the South German mixed bent seed can be distinguished 
and its true proportion determined. In mixtures of the commercial 
kinds determination within 5 per cent of the true proportions of 
redtop seed and seed of the fine bent grasses taken collectively can 
be made. The seed of the fine bent grasses found in South German 
mixed bent seed, exclusive of the velvet-bent seed it appears always 
