78 Forest Club Annual 



marked, since the older seeds almost invariably show a tendency 

 to germinate more slowly than fresh seeds. 



It is practically impossible to make a definite statement as 

 to the time elapsing between placing the seeds in the germination 

 apparatus and the beginning of germination. This will not only 

 vary with species but with individual lots of seeds within the 

 species. In general, the thin-coated seeds (Pseudotsuga ta.vi- 

 folia, Picea e.vcelsa, Abies concolor, etc.) can be relied upon to 

 commence germination much sooner than the thick-coated seeds 

 (Pin us Jeffreyi, Pinus edulis, Pin us cernbra, etc.) Zeberbauer* 



*Zederbauer, E. : Die Keimprufungsdauer einiger Koniferen. (Centbl. 

 Gesam. Forstw., 32:306-315). Abstract in Experiment Station Record, 18:147. 



made a large number of germination tests of various species of 

 coniferous seed to determine the period required for germination. 

 Most of the species of Picea, Pinus, Lariv, Tsuga, Sequoia, 

 Cryptomeria and Cupressus germinated in from 14 to 28 days 

 after placing in the germination apparatus, while Pinus strobus 

 required from 30 to 40 days. In soil tests the germination of thin-- 

 coated seed rarely commences before seven days have elapsed 

 after placing in the soil, and with the thick-coated seeds often 

 two months or even more is required. This immediately sug- 

 gests perliminary treatment of hard-coated seeds. Concentrated 

 sulfuric acid, for instance, dissolves the seed coat to a certain 

 extent and permits moisture to permeate more rapidly. Hiltner 

 and KinzeP treated Scotch pine seeds with concentrated sul- 

 furic acid for periods varying from ten minutes to one hour 

 and found that the germination was hastened and the final 

 germinative per cent increased directly with the length of treat- 

 ment. Germination* of white pine seed was materially hastened 

 by such treatment, one hour being the optimum time of treatment 

 since periods shorter and longer than this showed a falling off in 

 practical germination per cent as w r ell as final germination per 

 cent. A germination 3 of 24 per cent was secured with Pinus 

 cembra seed treated for twenty-one hours with concentrated sul- 

 furic acid, the seed having failed to germinate when untreated. 

 Hot water 4 at a temperature of 65 degrees C. applied for a period 



i, 2, 3, 4 Hiltner and Kinzel: fiber die Urachen und die Beseitigung- der 

 Keimungsbemmungen. Naturwissenscbaftlicbe Zeitscbrift fur Land und 

 rm-stwirtschaft, 4:44, 46, 47. 



of five minutes hastened germination and increased the final 

 germination per cent of white pine seed. 



Germination tests can never be absolutely exact, since from 



