128 BOTANICAL GAZETTE [February 



At 30 C. on moist filter paper the fresh seeds will usually give 100 

 per cent germination within 24 hours. The hypocotyls will attain 

 a length of 8-9 mm., and the cotyledons will be entirely spread. 

 Schroder (23) states that seeds of Caltha palustris failed to 

 germinate after 11 weeks of storage over sulphuric acid and after 

 20 weeks of storage in the ordinary atmosphere. Delavan (8), 

 working with the oaks and hickories, concludes that a cold even 

 temperature, although the atmosphere be moist, is better than warm 

 dry storage of seed. Seeds of Oxalis, elm, river maple, hornbeam, 

 birch, beech, chestnut, and probably many others have their 

 germinative power lowered or lost entirely by varying periods of 

 desiccation. 



Heretofore no work has been done on seeds, sensitive to drying, 

 regarding the exact or approximate water content at the time of 

 death. Furthermore, it has never been demonstrated whether loss 

 of viability is due in part to temperature or entirely to desiccation 



effects. 



■ 



Investigation 



River maple (Acer saccharinum L.) 



In the Chicago region Acer saccharinum matures its seeds 

 the latter part of May or early in June, varying with the season. 

 At the time of fall the seeds contain approximately 58 per cent of 

 water, being almost fully imbibed. The seeds soon germinate if 

 they lodge upon a moist substratum, but if they are subjected to 

 desiccation there is an immediate reduction of the moisture 

 content, and their viability is lost long before an air-dry condition 

 is attained. The seeds of the river maple were chosen for this study 

 because they are large, making it possible to obtain material readily 

 in sufficient quantities for chemical analysis. The period of time 

 between maturing and loss of viability is of moderate duration, 

 permitting a study of internal changes accompanying desiccation; 

 also seeds are abundant and easily collected. In all cases where 

 reference is made to the maple fruit the seed plus the ovary wall 

 is taken into consideration. Seed refers to the embryo plus the 

 integuments. In all storage conditions the entire maDle fruit was 



this 



The criterion 



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