472 BOTANICAL GAZETTE [December 



* Brain, Harry, Presoak method of seed treatment: A means of preventing 

 seed injury due to chemical disinfectants and of increasing germicidal efficiency. 

 Jour. Agric. Res. 19:363-392. 1920. 



10 Bews, J.W., Plant succession and plant distribution in South Africa. Ann. 

 Botany 34:287-297. 1920. 



11 Stork, Harvey E., Studies in the genus Taraxacum. Bull. Torr. Bot. Club 

 47:199-210. 1920. 





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25. 66 per cent in the fruit 14 days old to 48. 32 per cent in ripe fruit. Starch 

 decreases in the same period from 15.84 per cent to 2.65 per cent. Fruit 

 picked after it had started to color and allowed to ripen in free access of air 

 showed practically the same composition and edible qualities as fruit ripened on 

 the vine. Commercially ripened tomatoes, due to lack of free access of air, show 

 very different composition and inferior taste. Lack of ventilation during 

 ripening increased the acid content 138 per cent and decreased the soluble 

 carbohydrate content 21 per cent. Commercially ripened tomatoes wrapped 

 with one paper showed similar but less marked changes. Sando is unable to 

 explain why wrapping with three papers was less detrimental than wrapping 

 with one. — Wm. Crocker. 



Seed sterilization. — Braun 9 has developed what he calls the "presoak" 

 method of seed sterilization. "The use of formalin and copper sulphate as 

 now practiced usually causes retardation and injury to seed germination." He 

 finds that he can eliminate this injury by soaking the wheat seeds ten minutes 

 and covering them for six hours to allow them to absorb the adhering water. 

 Then follows the usual treatment with the disinfectant. The presoak method 

 often shows a noticeable stimulative effect. Braun speaks of presoaking as 

 saturating the walls and cells of the seeds so as to dilute the disinfectants 

 beyond an injurious concentration. He also speaks of presoaking as increas- 

 ing the efficiency of the disinfectants by bringing the dormant bacteria and 

 fungi into a vegetative state so they are more easily killed by the disinfectants. 

 — Wm. Crocker. 



Plant distribution in South Africa. — An analysis of the plant population 

 of South Africa by Bews 10 shows that while Willis's "age and area" theory 

 may be in general accepted, its application is not feasible in the region under 

 discussion, on account of the very great climatic variations. Species widely 

 distributed in South Africa are found to belong to pioneer stages of the various 

 plant successions, although not all pioneer forms are widely distributed. 

 Many species with a restricted distribution are shown to belong to climax 

 associations, especially in the coast belt forest of Natal.— Geo. D. Fuller. 



Studies in Taraxacum. — Stork 11 has extended our knowledge of this 

 interesting genus, discovering "parthenogenesis" in additional species, in the 

 sense that the unfertilized egg develops an embryo, but it is a diploid egg. He 

 also records some interesting variations in the genus, and gives an account of 

 megasporogenesis in T. erythrospermum. — I. M. C. 





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