Morphologie, Teratologie, Befruchtung, C5'tologie. 231 



Keeble, F., Gigantism in Primtila sinensis. (Journ. Genet. II. 2. 

 p. 163—188. pl. 11. 5 textfig. 1912.) 



Records the origin from normal ancestors of a giant form which 

 breeds true. Its gigantism is said to be due to that of its cells: the 

 nuclei are larger than usual, but details of the chromosomes are 

 lacking. It is moderately fertile with its own pollen, but sterile with 

 all other varieties. Genetically, gigantism is considered to depend 

 on three factors, and to be a dominant: semi-giant forms occur 

 which lack one or more of the factors. 



R. H. Compton (Cambridge). 



Kershaw, E. M., Structure and Development of the Ovule 

 of Bowenia spectabilis. (Ann. Bot. XXVI. 103. p. 625—646. 1 pl. 

 16 textfig. 1912.) 



The ovule of Bowenia resembles that of other Cycads in its 

 general development, but the nutritive layer in the sporangium is 

 used up earlier than in the other genera. The poUenchamber con- 

 sists of a narrow Upper region and a lower wider Chamber, persisting 

 after the upper one has shrivelled up. Brongniart's figures make 

 it clear that Cardiocarpiis augiistodensis had a similar poUenchamber. 

 The poUenchamber of Trigonocarpus 'when mature, closely resem- 

 bles that' of CardiocarpuSj though its young stages have not been 

 figured. There is no evidence that the Cycad poUenchamber has 

 been derived from one of the more complex kinds found in the 

 Lagenostomales; it may be more naturally compared to that of the 

 Medullosae of the Trigonocarpus affinity. The ontogeny of the 

 Cycadean-integument, seems to show that it is a homogeneous 

 envelope differentiating into three layers and not a phylogenetically 

 double structure formed by the fusion of a cypulelike body with a 

 Single integument. It has also been thought that the bundless of the 

 inner vascular series of the Cycad ovule, which in certain genera 

 run into the free part of the integument, were equivalent to the 

 integument bundles of Lagenostoma, while the outer series were 

 equivalent to the cupular bundles. But in certain cases the inner 

 series of bundles in Bowenia ran for a little way, into the nucellus; 

 they are moreover, concentric and branched in the Cycads and 

 collateral and almost unbranched in Lagenostoma. The principal 

 point in which Trigonocarpus differs from a Cycad seed is the 

 degree of union of nucellus and integument. 



Isabel M. P. Browne (London). 



Lundegärdh, H., Die Kernteilung bei höheren Organismen 

 nach Untersuchungen an lebendem Material. (Jahrb. wiss. 

 Bot. LI. p. 236-282. 1 T. 1 F. 1912.) 



Seine Beobachtungen hat der Verf. an frischen Schnitten durch 

 Wurzelspitzen von Allium cepa, Vicia faba und Cucurbita pepo an- 

 gestellt, deren Zellkerne während längerer Zeit in vivo betrachtet 

 wurden. Besonders AlHum cepa lieferte recht interessante Bilder, 

 die zeigen, dass manche in fixierten und gefärbten Präparaten beob- 

 achtete Struktur, die von der Kritik als künstlich und durch die 

 Fixierung verursacht bezeichnet worden ist, sich auch sehr gut im 

 Leben auffinden lässt. 



Im ruhenden Kern waren nur zweierlei geformte Bestandteile 



