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SUDAN GRASS AND RELATED PLANTS. 57 
The contrasting characters of the two seeds, as described by Hill- 
man, are set forth in Table XIX. 
It will be noticed that there is an overlapping in several of these 
characters, particularly in the size and color of the unhulled seeds; 
also that a small percentage of Sudan grass seeds has no portion of 
the rachis adhering and 
an equally small per- 
centageof Johnsongrass 
seeds is found in which 
a portion of the rachis 
adheres. In all such 
cases, however, Hill- 
man declares that an 
examination of the seed 
surface at the point of Fig. 24.—Sudan grass seeds, enlarged. Unhulled seeds, spikelets (1); 
attachment, the size of hulled grains (2): a, a, Seed stem; b, b, construction at the junction 
: of seed and stem; c, c, appendages of the seed with broken apexes; 
the seed, together with d, scar of the grain; e, embryo. 
the size, form, and color 
of the grain, should suffice to distinguish the seed of one grass from 
that of the other. Most States now have seed laboratories in connec- 
tion with their agricultural experiment stations. By referring sam- 
ples of all Sudan grass seed importations to the analysts in these 
laboratories the seed dealer may ascertain whether these samples 
are free from Johnson grass seed. . 
CULTURAL METHODS FOR SEED PRODUCTION. 
Most Sudan grass seed is produced in cultivated rows, because this 
method of planting with its accompanying cultivation more nearly 
assures a crop, especially 
in regions subject to 
drought. Table XX 
shows the yields obtained 
in both wide and narrow 
rows, as compared with 
broadcast or close drills. 
Table XX shows that 
cultivated rows give bet- 
Fic. 25.—Johnson grass seeds, enlarged. Unhulled seeds, spikelets ter yields of seed in the 
(1); hulled grains (2): a, a, Scar of the hull; 6, b, appendages of humid regions and also in 
the seed with expanded, cup-shaped apexes; c, scar of the grain; the semiarid regions if the 
d, embryo. i Thats 
cropis notirrigated. Un- 
der irrigation the results are reversed, the broadcasted or close-drilled 
seedings being markedly superior. Narrow rows, 18 to 24 inches apart, 
give larger yields than the wide rows, 36 to 44 inches apart, but it is 
hardly advisable for a farmer to plant in narrow rows unless he has on 
hand machinery adapted for their cultivation. Wide rows can be 
