ALFALFA SEED PRODUCTION. ah 
flowers that tripped first were on the outside of the plant. The 
screen was replaced, so that insects had no access to the flowers, nor 
was the screen again removed until the seed was mature. 
It was estimated that more than one-half of the flowers counted 
on each raceme thus became self-tripped before the screen was re- 
placed. None were artificially tripped, as extreme care was taken. 
The results are presented in Table XII. 
No flowers already tripped were noticed when the screen was first 
removed. Apparently the tripping was induced when the screen 
was removed by the increased transpiration from the turgid flowers. 
Certainly no insect agency was involved. The total number of pods 
produced was 23.7 per cent of the total number of flowers counted 
and tagged. | 
TABLE XI1.—Results obtained with a single alfalfa plant screened from insects and exposed 
for 15 minutes on a bright, warm day when vn full bloom, thus bringing about the auto- 
matic tripping of its flowers. 
Number of seeds. 

Flowers 
Number | Number : 
Raceme. of flowers.| of pods. bearing 
pods. Total Average 
per pod. 
Per cent 
INO; UEGSGCSS SH EHE AEROS KO ee Ae ee pal See em as Saye ei oes 26 10 38.4 13 1193 
IN@S Qeddbde SosobaebocdeesSenbos suse cBeaueebeHaeua aa 16 3 18.7 6 2.0 
IN@s Beccaceceeoosoode sauce seers Peas ale Sais baie 12 3 25.0 7 243 
ING) Gabsgse San ocasouoeseueebeo ee BaSEseanabsoseEsaneee 17 8 47.0 10 (2, 
IN@s Bogbeoesdcdcassoseaase cece se oboe acne aaeuiote aaseer 20 5 25.0 14 2.8 
IN@s Osgsossoses seonek Geshe ee ee eRe RSE see ace aaa 18 4 2282 8 2.0 
INOs (assadscuseuogogos GSS 5088 Hen DEE Ue Bere Soe ame eee 12 1 8.3 3 3.0 
INI@y Beds ccessbdsasscougeee eee ee eBA eds a Auoe Mae melee 22 3 13.6 6 2.0: 
INOS Qadadecododecsuoocdocosmenddseareraceaaene aeaapas 14 2 14.2 4 2.0 
INI@Y UO. cos sakocdboes 6s 4Ae Eb e aaa Sop oo Ss SeeeE Eanes 14 1 Teal 2 2.0 
IGS TU Soe Bea ales ge Se a ae eee ne 16 2 12.5 4 2.0 
ING) UPR oo so obae Boose oh Hod Bee w OMe Sores aplasia sect 18 2 11.1 5 2.5 
IN@s UB odsse6Socase56s Soe ob oR SAU Re ee aS BeBe Se sMO rE sees 17 6 35. 2 12 2.0 
IN@s We bec oo ddaos sobbed Susp a es@enie see ceceuore Busser 17 4 23.5 10 2.5 
ING, US soscacsscbsdssse4 seu eekeEoe be EE be EeecEness sre 24 5 20.8 10 2.0 
ING, UG ase ckcedectocneses ad MAS SRE Soar Se caee er mer ede 12 4 | 33.3 a te 2 
INO, Ue socceded Gocse ted opp obs Re bH ESE Bac Se Eee pee sae 20 7 35.0 12 1.7 
ADORNS eS SS a A a 295 EO Gea el ae E33 \i;| See ae 
ENS ODEOS CoE GU CCS ESBS OE Co ee DIESE Sear Ria ee ets aa mL Leal a My Pa Rs ene Shaan 1.9 

In 1910 an experiment was conducted at Pullman, Wash., for the 
purpose of determining what proportion of flowers became self- 
tripped. Accordingly, nine alfalfa. plants, which were producing 
more pods and seeds than most of the alfalfa plants in the experi- 
mental plats, were inclosed in netting tents and were closely ob- 
served for several days. , 
The tents in which the plants were inclosed were carefully covered 
with fine-mesh mosquito bar, so that no openings were left for honey- 
gathering insects to gain access to the flowers. The tents were made 
large enough and pains were taken so that no flowers which were 
being watched were in such a position that they could brush against 
the sides or top of the tent. 
