324 Morphologie, Teratologie, Befruchtung, Cytologie. 



Costerus , J. C. , Pistillody of the stamens in Nicotiana. 



(Rec. Trav. bot. neerland. IV. p. 221. 1908.) 



Gives a very careful description of the degrees of pistillody of 

 the stamens observed in Nicotiana affinis. The abnormal fiowers are 

 a little shorter than the normal ones, the corolla shows various 

 degrees of dialysis and the insertion of the stamen irregularities; 

 the pistill always proved undisturbed. 



The anthers bear a curved appendage at the top with a stigma- 

 like end or a threadlike appendage without Stigma. In the latter 

 case the thecae contained only a small quantity of pollen; in the 

 split however a hard brown corpuscle, which coincides with the 

 style and stigmalike appendage. The stronger this corpuscle is, the 

 less is the quantity of pollen in the same anther. 



A microscopical examination showed no difference between the 

 styles proper and the stylelike appendage. The sections of the ab- 

 normal anther showed a kind of placenta growing forth out of the 

 tissue towards which the valves of the anthers curve. As soon as 

 the placentas have assumed a certain proportion they commence 

 producing ovules, which instead of being anatropous like the nor- 

 mal ones seemed to be orthotropous. In one case judging from the 

 placentation, the carpel-like parts do not correspond to the carpels, 

 but are to be considered as consisting of two different halves as the 

 valves of the capsule of the pansy. According to this conception it 

 would be, the thecae having been transformed into carpels and the 

 anther comparable to two leaves. Of course each stamen should not 

 be compared to that, at best one could admit of a Splitting up of 

 the connective in tangential direction. 



Finally the author compares this case to those of Sempervivum 

 tectorum, Papaver Orientale, Tulip, Bocconia cordata offering suffi- 

 cient similarity. Th. Weevers. 



Hyde, Edith, The Reduction Division in the Anthers of 

 Hyacinthns orientalis. (Ohio Naturalist. IX. 1909. p. 539—544. PI. 32.) 



In the prophase of the heterotypic mitosis the chromatin net- 

 work passes into a continuous spirem without the formation of pro- 

 chromosomes. The spirem twists into 8 loops which become the 8 

 chromosomes, the loops later breaking apart at the center so as to 

 form 8 bivalent chromosomes. The chromosomes show a striking 

 difference in size and shape, four being very large and three quite 

 small, while the remaining chromosome is intermediate. The writer 

 believes that the two chromosomes which must have united to form 

 a bivalent chromosome are alike in size and shape, and that they 

 represent maternal and paternal bodies. 



Charles J. Chamberlain (Chicago). 



Me Allister s F., The development of the embryo sac of 

 Smilacina stellata. (Bot. Gaz. XLVIII. p. 200—215. pl. 15. Sept. 1909.) 



The megaspore mother-cell divides twice, forming four spores 

 which are difinitely formed cells provided with walls. The dividing 

 walls are afterwards absorbed, so that the four nuclei occupy a 

 Single cell cavity. Each of these nuclei next divides, so as to pro- 

 duce an eight-nucleate embryo sac which matures in the usual way. 

 It is argued that the first four nuclei of the embryo sac of Lilium 

 are to be regarded as megaspores. M. A. Chrysler. 



