RED-CLOVER SEED PRODUCTION. 15 
as often as three times a day. Many uncovered heads were partly 
destroyed by the grasshoppers, and this undoubtedly accounts for 
the small seed yield of the uncovered heads, since bumblebees were 
plentiful. 
HEADS COVERED AND NOT POLLINATED. 
Another experiment was conducted in order to determine whether 
clover heads kept covered during their entire blooming period and 
not pollinated could set seed. 
Plants having at least six heads which would come into bloom at 
approximately the same time were selected for this work. Fifty 
Fic. 5.—General view of the field in which the clover work was conducted in 1912 at Ames, Iowa. The 
stakes represent plants selected for individual pollination work. The cages in the background were 
used to test the efficiency of different insects as pollinators of red clover. 
plants at Ames and 25 at Altoona were selected in 1911 and 27 
plants at Ames in 1912. The average seed yields per head are shown 
in Table ITI. 
Taste III.—Average seed yields of clover heads which were covered with tarlatan and not 
pollinated. 
| Heads covered with tarlatan. 
Location, year, and number of plants. 
A B C D E F 
Anmesat Oli bOsplamism. 2-2-2. 2. - Ne are ae ep 0.1 0.11 0.15 | 0 0. 16 0 
EMroona OMI 2ouplanise saa: ss Sees cae eee .16 4 30 . 04 . 26 ne 
INTIME, UIA OURS Se Janse conndesdecscacsadsens Sen 0 oi 0 0 02 0 
ACTORERD, MPO ENNIS oF eo ngeedosaseagsenonooouas 08 | .17 oli . 009 14 . 04 
To the results presented in Table III may be added the results 
given in column E of the summary of Table II, where 145 heads were 
