1907] CURRENT LITERATURE 77 



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potassium permanganate. This new method gives ven^ good results and is 

 particularly useful when large quantities of tubers are to be treated. — E. Mead 

 Wilcox. 



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Mitotic figures. — The nature of the forces which determine the achromatic 

 figure is discussed by Hartog,^^ and speculations as to processes occurring in the 

 living cell are illustrated by ingenious experiments. Finely pulverized magnetite 

 under the influence of magnets was made to take the form of the familiar mitotic 

 figures. Photographs of these magnetic figures showing centrosomes, centro- 

 spheres, polar radiations, mantle fibers, and central spindles are given. Tripolar 

 and quadripolar spindles were easily produced. — Charles J. CiiAivmERLAiN'. 



The xerophytic character of gymnosperms. — Miss Stopes^^ has brought 

 together the data in reference to xerophily among the gymnosperms, and concludes 

 '^that the xerophytic characters of the Coniferales in many cases are not adapta- 



tions to xerophytic conditions in their own times, nor are they inherited' from 

 the remote past as vestigial characters, but are the result of physiological limita- 

 tions of the type of wood in this ancient and incompletely evolved group. In other 

 w^ords, their 'xerophytism' is not ecological, but phylogenetic." — J. M. C. 



Embryogeny of Gnaphalium. — The occurrence of parthogenesis in Anten- 

 naria suggested to ScniLLER^^ an examination of the nearly related genus Gna- 

 phalium. A study of G. supinum, G. stivaticum, and G, nliginosum showed the 

 normal formation of four megaspores in the nucellus, a normal embryo sac with 

 the rather extensive antipodal development characteristic of many Compositae, 

 and the regular occurrence of double fertilization. AVhen pollination is pre- 

 vented no embryos are formed. — Charles J. Chamberlain. 



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Course of pollen tube in Sibbaldia. — According to Albaxese,33 the growth 

 of the integument in S, prociimhens continues until the micropyle is entirely closed. 

 The pollen tiibe 



reaches the embryo sac. This course of the pollen tube and also the described 

 cases of chalazogamy are regarded not as primitive conditions hut as variations 

 from the porogamic type. Sibbaldia often shows several embryo sacs in a single 

 nucellus. — Charles J. Chamberl.ain. 



30 Hartog, Marcus, The dual force of the dividing cell. Part I. The achromatic 

 spindle figure illustrated by magnetic chains of force. Proc. Roy. Soc. London 76: 



548-675. pis, g-ii, 1905. 



3^ Stopes, M 



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is it an 



ecological" adaptation? New Phytol. 6:46-50. 1907. 



3* Schiller, Josef, Untersuchungen iiber die Embryogenie in der Gatiung 

 Gnaphalium. Oesterr. Bot. Zeits. 57:137-142. pi. 5- ^9^7- 



33 Albanese, Nicol5, Ein neuer Fall von Endotropismus des Pollenschlauches 

 und abnormer Embryosacksentwickelung bei Sibbaldia procumbens L. Sitzber. 

 Kais. Akad. Wiss Wien ii^:i-2a. i)ls. 1-2. loo^. 



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