506 Morphologie etc. — Physiologie. 



La degenerescence des deux sporoc5'-tes steriles y est tres precoce. 



Ces deux especes fönt la transition au cas extreme represente 

 par C. impatiens, chez qui le caractere archesporial du nucelle a 

 totalement disparu. 



La Sterilisation du sporange primitif s'est accomplie dans le 

 genre Cardamine: 



a) par evolution raccourcie (suppression des initiales, degeneres- 

 cence precoce des Clements sporocytaires, differenciation hätive de 

 la cellule privilegiee); 



h) par reduction du nombre des sporocytes, variant de 8 ä 1. 



Jongmans. 



Vandendries, R., Le nombre des chromosomes dans la 

 Spermatogenese des Polytrichum. (La Cellule. XXVIII. p. 

 257—261. li Fig. 1912.) 



D'apres les recherches de M. et Mad. Docters Van Leeuwen 

 la Spermatogenese dans le genre Polytvichnni serait caracterisee 



par une double reduction produisant des antherozoides ä — chro- 

 mosomes. 



Malgre de minutieuses investigations, le present auteur n'a 

 pu trouver dans les cineses antheridiennes, aucune trace de reduc- 

 tion et les multiples divisions observees ont montre, sans exception, 

 les caracteres de cineses somatiques ordinaires depourvues de tout 

 indice reductionel. Les recherches ont porte sur les especes P. pili- 

 fenctn, P. commune et P. j'unipeyiman. Les cineses successives qui 

 donnent naissance aux antherozoides sont toutes du meme valeur: 

 elles comportent toutes le nombre haploide, c'est ä dire six, et c'est 

 ce nombre de chromosomes que regoit chaque antherozoide. 



Jongmans. 



Bunzel, H. H., Oxidases in healthj^ and in curly-dwarf 

 potatoes. (Journ. Agric. Research. II. p. 373—404. 21 Fig. 1914.) 



The author publishes followingdiscussion of results and summar}^: 



Comparison of the curves of the healthy plants with those of 

 the diseased ones shovvs at a glance a greater oxidase activity in 

 the case of the curly-dwarf material This is true for both the tubers 

 and the foliage. It seemed desirable to express these differences in 

 some numerical form, and this Wtis done by taking the averages 

 of all the results obtained from material of the same type with the 

 same reagents. These averages were then easil}' compared. 



It was shown that healthy foliage yields juices of diminishing 

 oxidase activity from the time of sprouting up to about the fortieth 

 day of growth (as counted from the time of planting). For this 

 reason in this summary of averages must be included only those 

 of the results obtained with healthy leaves which were obtained 

 during the growth period of the diseased material examined. The 

 age of the diseased foliage collected ranged from 64 to 91 days; 

 age of the plants where the whole shoots were examined was from 

 45 to 58 days. 



The averages were calculated as follows: All of the data (oxi- 

 dase activities) obtained within the age periods mentioned were 

 added together with the figures obtained for the beginning and the 

 end of the period by interpolation from the curve. The sum, of 

 course, was divided bv the number of data added. 



