164 Varietäten etc. — Physiologie. 



peduncle arising from a shallow cavity. The skin is thick, rough, 

 green or yellowish green, abundantly covered with red dots like 

 that of a pear. The flesh is white, granulär, firm, juicy, sweet, 

 slightly acidulous with an agreeable quince-like perfume. Attempts 

 were made to poUinate flowers of Pyronia with pollen from various 

 pears, but no fruits were obtained. Pyronia seems to be nearer to 

 Cydonia than to Pyrus, ior the ovules, six in locule, are arranged 

 in two series of three, one superposed upon the other. In the 

 aggregate of its characters Cydonia Veitchii is intermediate between 

 the two parent-genera. Botanically the hybrid appears to be sterile, 

 but horticulturally it is decidedly fruitful, yielding an abundance of 

 wellformed, seedless fruits. 



This first attempt to hybridize the quince and the pear should 

 encourage plant breeders to make new attempts to combine the 

 quince with those primitive species of Pyrus which have given us 

 splendid and highly esteemed varieties of pears in such great 

 numbers. M. J, Sirks (Bunnik). 



Wolfe, T. K., Fasciation in Maize kerneis. (American 

 Naturalist. L. p. 306—309. 1916.) 



A preliminary communication abouttwo fasciated Maize kerneis, 

 found on „Improved Leaming" as seed parent with Boone County 

 as pollen parent. The pollen of the two varieties was mixed and 

 applied to the same ear. The fasciated kerneis contained two 

 embryos each; the normal cornkernel having the embryo on the 

 side toward the tip of the ear, these two had an embryo on both 

 sides. The stalks, resulted from these double kerneis produced two 

 ear shoots each; however only one ear shoot on each stalk produced 

 an ear. These ears were bagged and selfpollinated by band; none 

 of the resulting kerneis possessed two embryos like their parents. 



M. J. Sirks (Bunnik), 



Amstel, J. E. van, On the influence oftemperatureon 

 the COj-assimilation of Helodea canadensis. (Rec. Trav. bot. 

 neerl. XIII. p. 1—29. 1916.) 



The influence of temperature on physiological processes of the 

 yeast was studied by the author in 1912; she showed in her 

 publication that in general the studies on this subject have not 

 been carried out in such a manner that important conclusions 

 could be drawn from the results obtained. It was then especially 

 demonslrated that the present data do not answer to the question 

 whether there is a difference between the influence of a rise of 

 temperature on a physiological and on a physical or chemical 

 process. 



This influence has been studied on a great many physiological 

 processes; i. a. on assimilation (Blackman a.o.). The writer made 

 now the assimilation in Helodea canadensis the subject of an 

 extensive study; the apparatus is described in detail; the prepa- 

 ration of the water (distilled water with a quantity of potash was 

 used in many cases; in some preliminary experiments tapwater), 

 and the determination of the dissolved CO2 showed that the water 

 used contained in minimum 200 mgr. CO2 pro Liter (152 mgr. COg 

 dissolved in the water and 48 mgr. CO2 as equivalent to 109 mgr. 

 KHCO3 resulting from 75 mgr. potash which were added to the 

 water in the beginning of the preparation). 



