248 Varietäten etc. — Physiologie. 



4. There appears to be a slight negative correlation between 

 the number of fruits per inflorescence and the number of seeds 

 developing per fruit, i. e., a decrease in the number of seeds per 

 fruit is associated with the production of a number of fruits above 

 the average. This result reinforces the conclusions stated under (3). 



5. The intra-inflorescence correlation for number of seeds 

 matured is positive if onl}'' fertile fruits be included, but (apparently) 

 significantly negative, if sterile and fertile ovaries are taken at 

 random. Apparently, therefore: (a) the inflorescences vary in their 

 capacity for torming seeds, so that when one fruit is above the 

 average in seed production, the others of the same inflorescence 

 are also likely to be above the average in fertilit}'^; (b) the superior 

 fertility (seed production) of some fruits is likely to be attained at 

 the cost of the complete sterilization of other ovaries. 



6. There is a moderately high correlation between the weight 

 of the seeds of a fruit. There is, therefore some complex of factors — 

 innate vigor of ovules, availability of plastic materials etc., — tending 

 to render the seeds of a fruit alike. What these factors and their 

 intensities are, can only be ascertained bj' more detailed analysis 

 of more extensive data. Jongmans. 



Brannon, M. A., Osmotic pressure in potatoes. Contri- 

 butions from the Hüll Botanical Laborator}'^ 17 7. (Bot. 

 Gazette. LVI. p. 433-438. 4 Fig. 1913.) 



The author gives the following conclusions at the end of his 

 paper: Heat is a limiting factor in Controlling the processes v.'hich 

 develop the substances that give rise to Variation in osmotic pressure 

 in potato sap. 



Lowering temperature causes an increase in acidity, which in 

 turn seems to be the Controlling agent in the release of the enzymes 

 which hydrolize starch and hemicellulose. 



The carbohydrates hydrolized furnish the energy which is used 

 by the potato while carrying on its metabolism during cold storage. 



Jongmans. 



Davis, W. E. and R. Catlin Rose. The effect of external 

 conditions upon the af ter-ripen ing of the seeds of 

 Crataegus mollis. Contributions from the Hüll Botanical 

 Laboratory 157. (Bot. Gazette. UV. p. 49—62. 1912.) 



The seeds of the hawthorn do not germinate immediately after 

 the fruit has ripened, but have a latent period of one or more years. 



The cause of the delay is very largely in the hypocotyl rather 

 than in the cotyledons or any of the external structures. 



If the seeds are removed from the carpels and kept very moist 

 and at a temperature of 5° or 6° C, the latent period may be 

 shortened to 2,5 tili 3 months, and if the testas are removed and 

 the embrj^os treated, the period may be reduced to 30 days. Tem- 

 peratures below 0° C. are not favorable for after-ripening. Seeds 

 kept at —2° to —3' C. did not after-ripen. Seeds atO°C. after-ripened, 

 but not so readily as those kept at a few degrees above 0° C. The 

 most favorable temperature for after-ripening seems to be 5°— 6° C. 



Low temperatures alternating with high temperatures are not 

 favorable for after-ripening. 



If the seeds are removed from the cold Chamber before they 

 have passed through the after-ripening period and subjected to the 



