1921] HARRINGTON—GERMINATION 357 
plete in fewer days than are indicated for the completion of the 
test, and perhaps in exceptional cases a few days longer will be 
necessary. 
Petunia seeds are the only kind for which an alternation of 
temperatures is recommended, although sweet peas also will 
germinate as well at 20°-30°C. as with a constant temperature. 
TABLE IV 
CONDITIONS RECOMMENDED FOR USE IN MAKING GERMINATION TESTS 
No. OF DAYS FOR 
SEEDS SuB- TEMPERATURE 
icemreeaci: Preliminary | Complete 
estimate test’ 
IT A oe AEN a on gee ea BB* 20°C 3 5 
iornia Downy. | co BB 20° 3 8 
RAYON ee TB 20° 3 8 
ROS oe eo ee ee ar BB 20 3 6 
TON ee a TB 20° 2 5 
ERONNON Sc a BB is” 8 15 
POST 8 a ee BB 20° 3 6 
Minnonette: 6 ae BB 20° 4 8 
MaRS Oo oe . ne 7 tO 
beta ky APRA WEL enees eas TS: rig 6 12 
20°—30° 
stig ee emer yee oe TB { 22.°C Mt 5 e 
Be Ce rer ae PEO NUYS Ea Bk es a TB 2 
Papaver somniferum................ TB 15° 4 8 
Winer poppies.) sce ee TB 1s 5 10 
bak ee ee nee TB _ 20° 3 6 
ORDUIRCON i oc ak ee: TB 17.5° 6 10 
fo] 
Ai oe ee ee 
Ret ee tr BB 20 3 6 
fa oe used in this column indicate; BB, between blotters; TB, top of blotters; C, cloth (canton 
nnel), 
} Either temperature condition may be used, but 20°-30°C. is probably preferable for petunia. 
Petunia seeds will germinate almost as well, and frequently quite 
as well with the constant temperature 22.5° or 25°C. as with the 
alternation 20°30° C., and either of these constant temperatures 
may be used for approximate results when it is inconvenient to 
Maintain the two temperatures 20° and 30°C. Nasturtium, 
pansy, and snapdragon seeds will germinate about as completely 
(although more slowly) with the constant temperature 15° as 
17.5°C. These kinds may be tested also at 20°C., although a 
