SEED CHARACTERS OF SUDAN GRASS AND JOHNSON GRASS. 
What appear to be exceptions to the general rule of seed fall 
occur in both kinds of seed, but the presence or absence of the 
distinguishing suture is evident under a 
good magnifier. 
DISTINGUISHING CHARACTERS OF THE 
SEEDS OF SUDAN GRASS. 
Sudan grass seeds in the hull (fig. 3,1) 
vary from eighteen one-hundredths to 
twenty-five one-hundredths of an inch in 
length, exclusive of the short stem. Most 
of the seeds bear at the base of each a 
short stem (fig. 3, a), which is jaggedly 
broken at its extremity. This stem repre- 
sents the upper portion of a rachis segment 
and is expanded at its articulation with 
the spikelet, or seed. The articulation may 
be marked by a slight constriction (fig. 3 7 
h), but it has no distinct suture. The ap- 
pendages of the spikelet usually are jag- 
gedly broken and not expanded at the 
apex (fig. 3, c). The missing portion corre- 
sponds tO the Short Stem of the spikelet FlG - 2 --Seed cluster of Johnson grass, 
j ., , enlarged: a, a, Fertile spikelets; b, b, 
QeSCriDeQ. sterile spikelets; c, c, axis, or rachis, 
The seed hull is mainly straw colored of the clustered, pedicels of sterile 
. . .. _ _. .. . flowers; e, e, sutures at the articula- 
or light tawny. Many seeds are tmged tion of spikelets with the axis; /, 
or spotted with brown. Some are tinged branch of the ^florescence bearing 
tiifi spp(1 olnstiPT 
or spotted with red. The darkest are 
blackish brown. In general, commercial seed has a smaller pro- 
portion of reddish and blackish brown seeds than Johnson grass. 
The hulled grains 
(fig. 3, 2) vary from 
thirteen one-hun- 
dredths to eighteen one- 
hundredths of an inch 
in length and are light 
reddish brown. They 
are larger, more com- 
monly elliptical in out- 
line, and lighter colored 
than in Johnson grass. 
Even in the smaller 
grains the embryo is relatively larger than that found in Johnson 
grass seeds. 
J^!\ 
Fig. 3.— Sudan grass seeds, enlarged. Unhulled seeds, spikelets (1); 
hulled grains (2): a, a, Seed stem; b, b, constriction at the junction 
of seed and stem; c,c, appendages of the seed with broken apexes; 
d, scar of the grain; e,. embryo. 
