300 BOTANICAL GAZETTE [april 



duration of the experiment was 38 days. At the end of that time 

 the only germinations obtained were those in the potassium nitrate, 

 and in no case did these exceed 4 per cent. The seeds in the stronger 

 mercuric chloride solutions were killed. 



The role played by the coat in the behavior of the seeds has not 

 been determined. Of naked embryos placed on moist cotton 32 

 per cent developed chlorophyll within a week, formed the hypocotyl 

 arch, and attained a length of 5-10 mm. Naked embryos pre- 

 viously soaked in dilutions of hydrochloric acid and butyric acid 

 and then placed on moist cotton gave no better results. 



Seeds treated with concentrated sulphuric acid for 4-60 min- 

 utes and then kept under various conditions in regard to Hght, 

 temperature, and oxygen pressure have never given over 20 per cent 

 germination. A slight forcing effect by low concentrations of 

 sulphuric acid was observed on seeds previously treated with con- 

 centrated sulphuric acid for 2-14 minutes and kept in the light 

 at room temperature. Seeds immersed for 5 minutes in water at 

 40° C. in 55 days gave 25 per cent germination. Reheated at the 

 same temperature for 3 minutes, 33 per cent germinated after 40 

 days. Longer heating at 40° C. or up to 70° C. gave lower per- 

 centages of germination. Untreated seeds gave no germination in 

 the same length of time. 



These results emphasize the following facts concerning the 

 conditions necessary for the germination of Samhucus seeds: (i) 

 air-dry seeds with a moisture content of 6 per cent or fresh seeds 

 with a moisture content of 22 per cent will not germinate when 

 placed on a moist substratum at room temperature; (2) this is not 

 due entirely to injury resulting from drying, although that may be 

 one of the determining factors; (3) air-dry seeds are able to absorb 

 water to the extent of approximately 40 per cent of their air-dry 

 weight, indicating that failure to germinate is not due to lack of 

 water ; (4) the effect of chemicals upon air-dry seeds is not marked, 

 a slight forcing effect of several acids, bases, and salts has been 

 observed, among which substances are found nitrates and sulphates ; 

 (5) the role played by the coat in the behavior of the seed has not 

 been fully determined; (6) a sHght forcing effect by low concen- 

 trations of sulphuric acid and by water at 40° C. has been observed; 



