Descendenz und Hybriden. — Morphologie und Teratologie. 595 



des cordons. Cette cause d'epaississement etant exclusive dans 

 le Trachycai'piis excelsiis, et certaine pour une premi^re phase 

 dans les Livistona, tandis que dans une seconde phase toute 

 la masse du parenchyme fundamental se divise, est cause de la 

 neoformation du nouveau parenchyme, de nouveaux faisceaux 

 et de nouveaux cordons. Enfin l'accroissement du stipe cesse 

 lorsque le parenchyme fondamental se transforme en scleren- 

 chyme; si la transformation est generale (Tracliycarpiis excelsus) 

 l'accroissement cesse completement ; si la transformation est 

 partielle, le stipe augmente seulement par l'activite des Clements 

 non sclerifies (Livistona). L. Pampaloni. 



COPELAND, E. B., The Variationofsome CaliforniaPlants. 

 (Bot. Gaz. Vol. XXXVIII. p. 401—426. 9 fig. Dec. 1904.) 



Notes on variations in leaf form in a number of California 

 plants; mainly several species of Qiiercus, Rliamniis californica, 

 Arctostaphylos tomentosa, Baccharis piliilaris, Caenothiis sore- 

 diatiis. Also notes on some abnormal forms of fronds of va- 

 rious ferns. The author uses his observations as a basis of 

 discussion of the mutation theory. States that he does not 

 believe there is any essential distinction between mutations and 

 „ordinary variations". His conclusion is as follows. „In this 

 part of California, where conditions are locally very diverse, 

 plant are more variable congenitally than in regions where the 

 environment is uniform. For in the latter, natural selection acts 

 along the same line on many generations, and the more closely 

 plants breed true to forms fitted to their uniform environment, 

 the better are their chances of perpetuation; while here natural 

 selection is unlikely to work in the same way on many gene- 

 rations of variable plants; and breeding very close to a form 

 fitted to any one sort of environment decreases the number of 

 the plant's prospective descendants. For this reason , the ubi- 

 quists in this region are more variable than the plants of re- 

 stricted occurence. Their Variation enables them to be ubiquists, 

 and being ubiquists keeps them variable. „Mutations'' or dis- 

 continuous variations, and the most insignificant of individual 

 variations are parts of one unbroken series." 



H. M. Richards (New-York). 



MONTEMARTINI, L., Sul valore morfologico deU' ovario 

 e deir ovulo della Canapa. (Rendic. Congr. Botan, di 

 Palermo. 1902. p. 155—164.) 



L'auteur applique l'etude de la distribution des faisceaux ä 

 l'interpretation de la valeur morphologique de la fleur femelle 

 du chanvre. D'apres ses observations et celles de MM. Briosi 

 et Tognini, il demontre que, comme l'a vu M. Zinger, les 

 fleurs femelles se deveioppent deux par deux ä l'aisselle des 

 feuilles et representent les premiers petits rameaux de troisieme 

 ordre du rameau secondaire axillaire, qui se developpe entre eux. 



38* 



