22 JULIUS VALENTINE HOFMANN 



It is known that seeds of other plants are viable for long periods, and 

 the writer has known wild oat seed (Avena fatua) to remain in soil for 

 seven years and produce a good germination the year it was plowed up. 



Becker 2 draws the conclusion that oxygen acts as a stimulant in seed 

 germination, and many of the conditions under which the seed germinates 

 or does not germinate seem to bear this out. 



Hatfield's 3 work on the Vitality of Seed showed that the Hibiscus 

 militaris germinated after ten years, Rocky Mountain columbine after 

 six years, tobacco, verbenas, ageratum, after several years' storage. 



Duval 4 found the following seeds germinated after being buried in 

 layers of clay, not below the frost line, for three and a half years : Trifolium 

 pratense, Trifolium repens, Polygonum avariculare, Bursa pastoris, Anthemis 

 cotula. The soil was taken into the greenhouse and the seed germinated. 



Beal 5 secured some germination from the following seeds after they 

 had been stored in soil for twenty years: Amaranthus retroflexus, Brassica 

 nigra, Capsella, Bursa pastoris, Lepidium virginicum, Anthemis cotula, 

 Malva rotundafolia, Rumex crispus, Verbascum thapsus, Stellaria media, 

 Polygonum hydropiper. 



These experiments give some idea as to the viability of the seed of 

 some of the common and well-known weeds. Most of these have seeds 

 with very thin seed-coats that are easily soaked with water. It is very 

 probable that seed of the conifers with more or less resinous seed-coats 

 would remain viable for a longer period. The characteristics of some of 

 the coniferous seeds are well known, such as the western white pine, 

 Douglas fir, eastern white pine, and the junipers. The seeds of these will 

 often not germinate for two or three years even under the best of con- 

 ditions in the nursery. Certainly they will remain viable as long or even 

 longer when in the forest floor under unfavorable germinating conditions, 

 but at the same time under good storage conditions. 



Conzet 6 showed that the seed of the Norway pine (Pinus resinosd) 

 remained in the forest floor for three years and then produced good germi- 

 nation. 



The results of the study of the Yacolt burn are a practical demonstra- 

 tion of the viability of coniferous tree seeds. The study showed that 

 reproduction occurs over the entire burn. The seedlings which germi- 

 nated from one to three years after the fire vary in density, regardless 

 of the location of seed trees, while the seedlings germinating later than this 



*H. Becker, Uber die Keinung verschieden artiger Fruchte und Samen bei derselber Species. 

 Beihefte Botanisches Centralblatt 29:21-143. 1912. 



1 T. D. Hatfield, Vitality of seed. Garden and Forest p. 297. 1897. 



4 Duval, in the Botanical Gazette 37:146-47. 1904. 



5 Beal, Vitality of seeds. Botanical Gazette 37:222. 1904. 



* G. M. Conzet, A qualitative and quantitative study of the seed production and reproduction of 

 Norway pine (Pinus resinosa). Master's thesis, the University of Minnesota. , 1913. 



