Physiologie. 1 19 



Es stellte sich nämlich heraus, dass es nicht gleichgültig 

 ist, zu welcher Tageszeit die Versuche angestellt werden. Wird 

 ein Versuch Morgens zwischen 6 bis 8 Uhr eingeleitet, so hört 

 im reinen Wasserstoff die Plasmaströmung nach 5—10 Minuten 

 auf. Wurde dagegen am Abend eingesammeltes Material ver- 

 wendet, so dauerte unter sonst gleichen Bedingungen die Strö- 

 mung 2—4 Stunden an. Zur Mittagsstunde angestellte Versuche 

 ergaben ein Resultat, welches zwischen diesen beiden extremen 

 Ergebnissen ungefähr die Mitte hält. 



Verf. vermuthet nun, dass in Folge der Assimilation am 

 Tage sich Kohlenhydrate, vor allem wohl Glukosemengen, an- 

 häufen und diese eine gesteigerte intramoleculare Athmung er- 

 möglichen. Kolkwitz. 



TiMBERLAKE, H. G., Starch-Formation in Hydrodlctyon utri- 

 culatiim. (Annais of Botany. Vol. XV. No. 60. p. 619. 

 Dec. 1901.) 



After quoting the conclusions of previous observers, such as 

 Schmitz, Meyer, Schimper, Klebs, and others as to the 

 origin of starch in plants having pyrenoids, the author 

 describes his own results with Hydrodictyon. He points out, 

 to begin with, that there is here no chromatophore; the Chloro- 

 phyll is distributed in the peripheral layer of the cytoplasm, in 

 which also lie the nuclei and the pyrenoids. He observed the 

 formation of starch, and found it to take place by the conversion 

 of a portion of the substance of the pyrenoid into a starch- 

 grain. By a repetition of this process great numbers of starch- 

 grains are formed: but all of them are „pyrenoid-starch'- ; there 

 is, here at any rate, no „stroma-starch" as suggested by previous 

 olDservers. Previously to the development of the reproductive 

 cells, the starch-grains undergo Solution, and the pyrenoids dis- 

 appear : hence the pyrenoids must be formed de novo in the 

 young cells. The resting pyrenoid is homogenous in structure 

 and spherical in form. S. H. Vines. 



Kny, L, On Correlation in the Growth of R!oots and 

 Shoots (Second paper). (Annais of Botany. Vol. XV. 

 No. 60. p. 613. Dec. 1901.) 



The author here replies to the criticisms of H er ing (Jahrb. 

 wiss. Bot. XXIX. 1896) upon the conclusions which he stated 

 in his first paper on this subject (Ann. of Bot. VIII. 1894), that, 

 namely, in seedlings (Vlcia Faba and Zea Mays) root and shoot 

 are in a high degree independent of each other in their growth, 

 whilst in the case of cuttings (of Salix acuminata and piirpurea) 

 the effect of the repeated removal of the one organ soon becomes 

 apparent in the diminution of the other. He quotes the results 

 of Townsend (The Correlation of Growth under the Influence 

 of Injuries. Ann. of Bot. XI. 1897) to prove that Hering's 

 apparent correlation between root and shoot in seedlings is due 



