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Botany. — '^On the influence of the nectaries and other sugar - 

 containing tissues in the flower on the opening of the anthers " 

 Bj Dr. W. BuRCK. (Communicated bj Prof. F. k. F. C. Went.) 



(Communicated in the meeting of September 29, 1906). 



The consideration that the opening of the anthers is preceded bj 

 a very considerable loss of water ^) and that with very many plants, 

 e.^. Compositae, Papilionaceae, Lobeliaceae, Antirrldneae, Rhinantha- 

 ceae, Fumariaceae and further with all plants, chasmogamous as 

 well as cleistogamous, which fertilise in the bud, this opening takes 

 place within a closed flower and consequently cannot be caused by 

 transpiration to the air, gave rise to the question whether perhaps 

 the nectaries or other sugar-containing tissues in the flower, which 

 do not secrete nectar outwardly, have influence on the withdrawal 

 of water from the anthers. 



My surmise that also among the plants whose anthers only burst 

 after the opening of the flower, some would be found in which this 

 process is independent of the hygroscopic condition of the air, was 

 found to be correct. If the flowers are placed under a glass bell-jar, 

 the air in which is saturated with water- vapour, the anthers of many 

 plants burst at about the same time as those of flowers which are 

 put outside the moist space in the open air. 



This led me to arranging some experiments, yielding the following 

 results : 



1. If in a flower of Diervilla ( Weigelia) rosea or jloribunda, 

 which is in progress of unfolding itself, one of the stamens is squeezed 

 by means of a pair of pincers, so that the drainage of water from 

 the stamen downwards is disturbed, the four anthers whose stamens 

 have remained intact, spring open, but the üfth remains closed. 

 With this plant it is not necessary to place the flower in a moist 

 space; the same result is generally obtained if the flower remains 

 attached to the plant. 



If a flower is placed in the moist space together with the loose 



1) This loss of water amounts e.g. with FrUillaria imperialis to 90 % of the 

 weight of the anthers, with OrnUhogalum umbellatum to 86 %, with Diervilla 

 floribunda to 87%, with Aesculiis Hippocastanum to 88%, with Pi/rns japo- 

 nica to 80 7^, with different cultivated tulips 59—68 %. etc. With plants whose 

 anthers burst in the flower, the loss is smaller ; the anthers and the pollen remain 

 moist then. With Oenothera Lamarckiana the loss amounts to 41 %, with 

 Canna hybrida grandiflora to 56 o/o, with Lathyrus latifolius to 24 7». 



