HORTICULTURE AND LANDSCAPE GARDENING. 145 



5. Why are toukg trees barren? — It is well known that the blossoms 

 of young and vigorous trees seldom perfect fruit. The reason of this fail- 

 ure has been sought in various directions. It is sometimes stated that the 

 pistils are imperfect, sometimes that the anthers are not developed and that 

 pollen is therefore deficient. So far as opportunity offered, observations 

 were made to determine these points. 



wt?jA Transparent crab, a year old and standing in a nursery row, produced 

 flowers with abortive anthers. In all other cases which came under my 

 notice, the flowers were perfect. Sometimes the flowers set fruits which 

 grew for several days after the falling of the flower. This was conspicuously 

 the case in a Montreal Beauty crab which had been grafted last year on the 

 wild choke-berry {Pyrus arhutifolia), in a young tree of Elton cherry, and 

 in one of Prunus^ Simoni. In general, it is evident that the failure to set 

 fruit is not so much due to an imperfection in the flower as to the great 

 vigor of the young tree. It is well known that over-vigorous trees of any 

 age do not bear liberally. "Checking growth induces fruitfulness." The 

 energy of the plant is consumed so much in the growth of wood that fruit 

 production suffers. For the same reason, no doubt, the early varieties of 

 potatoes do not set so many seed-balls as the late varieties, the vital energy 

 being earlier diverted into the production of tubers. In the same manner, 

 also, can be explained the comparative failure to produce seeds in those 

 plants which produce very vigorous stolons, rhizomes, or other means of 

 propagation. 



6. Germination OF seeds which have been kept on ice. — Seeds from 

 plants which have been grown for some years in a cold climate often germi- 

 nate relatively earlier in spring than those from the same species grown in a 

 warmer climate. It is supposed by some that the reason of this quicker ger- 

 mination, or more properly, this greater sensitiveness to heat and other influ- 

 ■ences of spring, is in some way connected with the freezing of the seed. In 

 other words, it is maintained that the subjecting of the seed to a low tempera- 

 ture causes it to germinate at a lower temperature than one which has not 

 been so treated ; or that, at the same temperature, the seed which has been 

 kept uniformly cold will germinate sooner than the other. The same appears 

 to be true of plants as well. " Professor Simpson and Mr. Stewart, of 

 Scotland, acting upon this suggestion, kept alpine seeds and plants in an ice- 

 house during winter ; and these, when placed in the open ground, grew 

 more rapidly than those kept in the usual way."* 



Two years ago, various seeds were kept on ice during the winter and dupli- 

 cate sets were kept in a warm room. Both lots were sown the following 

 spring, but for some unaccountable reason very few seeds of either lot grew. 

 Last March a similar experiment was placed in the hands of one of my stu- 

 dents, J. 0. Duffey of the class of 1887. Seeds of lettuce, Brussels sprouts, 

 radish, cucumber, and parsnip were used, one lot of each being kept on ice 

 two months, the other lot being kept in a warm room. Early in May the 

 seeds were sown in florist's earth, and the results noted for several days. In 

 general, the seeds kept oq ice appeared to germinate sooner than the others, 

 but the results were discordant and not strongly marked. We hope to repeat 

 the trial upon a larger scale. 



7. Growth of plants from soaked seeds which have been dried. 



* Crozier, Modification of Plants by Climate, 23. 



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