Cytologie u. Befruchtung. — Morphologie — Algae. 403 



dividing pollen-, spore- and embryosac-mother-cells, and the 

 multipolar diarchal spindle Anlage described for vegetative 

 cells Hus. 



Thomson, R. B., The megaspore-membrane of the 

 Gymnosperms. (University of Toronto Studies, Biol. 

 Series, 4. p. 1—64. 5 pls. Toronto 1905.) 



The author has investigated the structure of the vestigial 

 megaspore membrane of the various Gymnosperms, with the 

 aim of discovering a basis for their phylogenetic filiation. The 

 conclusions reached are summarized by the author as follows: 

 From the standpoint, of the relative development of the 

 megaspore coat and the tapetum, vve are to regard the Abie- 

 tlneae as the most ancient group of the Coniferales; the Taxeae 

 as the most recent; the Taxodineae and Podocarpeae as com- 

 plex groups with some forms as ancient as or even more 

 ancient than the Abietineae, and other forms quite recent, 

 while Ciipressineae are considered as occupying a somevvhat 

 intermediate position in the phylogenetic series. 



E. C. Jeffrey. 



Life, A.C., An 3.hnovm2L\ Ambrosia. (Bot. Gaz. Vol. XXXVIII. 

 1904. No. 5. p. 383—384.) 



An plant of Ambrosia artemisiaefolia, which had received 

 mechanical injuries, produced flowers which showed abnorma- 

 lities, such as pollen arrested in development etc. In both 

 staminate and pistillate flowers parts had been replaced by 

 vegetative buds. The conclusion is arrived at that under the 

 abnormal conditions described the primordia that usually form 

 reproductive parts produced vegetative parts. Hus. 



COMERE, J., De l'influence delacompositionchimi- 

 que du milieu sur la Vegetation de quelques 

 algues Chlorophyce'es. (Bull. Soc. bot. de France. LH. 

 1905. p. 226—241.) 



L'auteur conclut de ses recherches que: 1° le degre de 

 reslstance physiologique des algues superieures filamenteuses 

 d'eau douce ä l'action des Solutions salines, moins elev^ que 

 celui des formes protococcoides, est variable avec les agents 

 chimiques, les diverses especes du meme genre et en fonction 

 de la graduation progressive dans l'action des matieres salines; 

 2" il existe pour chaque plante et pour chaque compose chimique 

 des doses Optimum et nocive; 3*^ les precautions ä prendre 

 dans les essais d'adaptation sont tres-importantes; 4^ les sels 

 employes, ne depassant pas les limites de la döse Optimum, 

 produisent une acc^l^ration de croissance et une action 

 speciale sur la coloration des chromoleucites; le chlorure 

 de sodium est trfes favorablement tolere; 5" les sels arseni- 

 caux ne peuvent remplacer les phosphates dans les liquides 



26* 



