RED-CLOVER SEED PRODUCTION. 29 
RELATIVE EFFICIENCY OF BRUSHES WHEN THE CLOVER HEADS WERE STRUCK 
VERTICALLY. 
= 
In order to test the efficiency of brushes in promoting cross-pollina- 
tion by carrying pollen from one plant to another on the bristles of 
the brushes, experiments were conducted at Ames, Iowa, in the 
summer of 1911 on plats 13 to 20 with different pairs of brushes. A 
vertical stroke on each of three mornings, three days apart, was 
given. The plats were 4 feet square. At maturity all heads from 
each plat were collected, kept separate, and later thrashed. 
The experiments on plats 21 to 28 were the same in all respects, 
except that one treatment when the flowers were in early bloom, 
instead of three treatments, was given each plat. Plats 9 and 10 
were used as checks. The results are presented in Table IX. 
Taste IX.—Average seed yield per head obtained when clover heads were struck vertically 
with different types of brushes at Ames, Iowa, in 1911. 
Plats given three treat- Plats given a single treat- 
Strokes ments. ment. 
Brush used. Ae 
’ 3 ment. Plat Heads |Seedsper| Plat Heads |Seeds per 
No. worked. head. No. worked. head. 
WICC epee Bie Res poe 7 ory Ci Ro ea EY 9 532 55.4 9 532 55.4 
JDO) seh Sees ee ee eee ye an |e ea 10 470 50.9 10 470 50.9 
1B se Ses Rega eo i 13 366 37.0 21 442 46.8 
DNS U8 Se Ree ee ne ea eet ee ae 1 14 490 42.0 22 440 33.8 
4 Ses Be CUR e aes Bc 2a Jet Ooo SaaS 1 15 440 42.1 23 420 45.0 
(Crp ea far ae eee tS 1 16 521 45.3 24 415 38.9 
pny aes ether AEE reese aes ky 1 17 416 39.3 25 380 54.5 
1D ia 5 SAP Se ce rae es Ses Se panne a 1 18 476 Sleil 26 400 45.9 
Gane een) ig he Pees Sat ve ae 1 19 510 41.8 27 430 48.1 
NDE eps ey ode tae eas one aoe Sere 1 20 462 44.7 28 436 49.0 
Table LX shows that with the exception of plat 25 the treatment 
considerably reduced the yield below that of the lowest yielding check 
plat. The results of the treated plats 13 to 20, inclusive, taken as a 
whole show a decrease of four seeds per head less than the yield of 
plats 21 to 28,inclusive. This may be accounted for by the fact that 
plats 13 to 20, inclusive, received two more treatments with the 
brushes than plats 21 to 28, inclusive, and were therefore subject to 
more injury from the bristles of the brushes. It will be seen from 
these experiments that the vertical strokes with the brushes proved no 
more efficient than the horizontal strokes in the production of seed. 
RELATIVE EFFICIENCY OF BRUSHES WHEN PRESSED TOGETHER BELOW THE CLOVER 
HEADS AND PULLED UPWARD. 
Experiments were conducted in the summer of 1911, at Ames, Iowa, 
to determine the efficiency of pressing a pair of brushes together below 
the clover heads and pulling them upward with considerable force, 
but still not enough to break off the heads. The plats were 4 by 4 
feet in size. Pair A of the brushes was used. Three treatments 
