NOTES AND COMMENT 



In laboratory experiments with water-cultures of higher plants it is 

 usually expedient first to germinate the seeds to be used, and this de- 

 mands the use of some medium in which germination will readily take 

 place and from which the young seedlings may easily be removed with 

 the least chance of injury. White pine sawdust, chopped sphagnum 

 moss and quartz sand are commonly used for this germinating medium, 

 but the first is becoming practically unobtainable, the particles of the 

 other two materials cling tenaciously to the root surfaces and the proc- • 

 ess of removing the plantlets from the same mass is commonly accom- 

 panied by more or less injury. It was suggested to the writer that 

 granulated cork might be suitable for this purpose, and, accordingly, 

 this material was given a rather thorough test in connection with other 

 experimental work which was carried out in the spring of 1911, at the 

 Laboratory of Plant Physiology of the Johns Hopkins University. 

 While the material here brought forward may well have been used by 

 others, no note to this effect has been met with in the literature, and 

 the apparently general utility of this method makes it seem advisable 

 to publish the present observations. The granulated cork used was 

 that which arrives in the American market as packing for Malaga grapes. 

 This may be procured at a negligible cost from fruit dealers. The un- 

 used material may of course be obtained from dealers in cork. The 

 cork was first sorted to remove grapes or other foreign bodies, and was 

 then thoroughly washed in water. On removal from the washing vessel 

 the cork was pressed between the hands to remove excess of water, and 

 was then rather firmly packed in ordinary porous flower pots of the 6- 

 inch or 8-inch size. The best germination was obtained when the seeds 

 were planted nearly or quite twice as deep as the same form would be 

 planted in sand. The pots stood, during germination, in water to a 

 depth of about two centimeters, the level of the latter being kept approx- 

 imately constant from day to day. It is well to let this level be auto- 

 matically maintained by means of the ordinary Marriotte flask. The 

 pots may be watered from above with practically no danger of raising 

 the moisture content of the cork above the optimum; any excess of 

 water rapidly drains away. Germination seemed to be somewhat 



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