Morphologie, Teratologie, Befruchtung, Cytologie. 387 



nucluar membrane to distend, and the nuclear cavity to expand. 

 As growth proceeds, the membrane is gradually withdrawn from 

 the chromatin mass within, and a large clear area of nuclear sap 

 is formed, containing the mass of chromatin, which has been left 

 at one side. There is no evidence that any actual contraction of the 

 chromatin takes place. 



The author is convinced that the so-called "contraction stage" 

 has nothing to do with the blinding or fusion of maternaland paternal 

 chromatin, and consequently pla} 7 s no immediate röle in the process 

 of chromosome reduction. Agnes Arber (Cambridge). 



Miyake, K. and K. Yasui. On the Gametophytes and Em- 

 bryo of Pseudolarix. (Ann. Bot. XXV. p. 639—647. pl. 48. 1911.) 



In this paper Pseudolarix Kaempferi, the only species in the 

 genus, is investigated, and it is found that the structure and deve- 

 lopment of the gametophytes, and the embryogeny, are of the nor- 

 mal Abietinous type. The number of chromosomes in the game- 

 tophyte is 12, and the number of archegonia in a Single ovule varies 

 from 4 to 7. The megaspore membrane is well developed in the 

 mature prothallium. and is similar in structure to that of other 

 Abietineae. Agnes Arber (Cambridge). 



Pearson, H. H. W., On the Microsporangium and Micro- 

 spore of Gnetum, with some Notes on the Structure of 

 the Inflorescence. (Ann. Bot. XXVI. p. 603— 520. pl. 40— 41. 1912.) 



The structure of the male spike in the genus Gnetum has been 

 investigated in detail by the author, and some interesting morpho- 

 logical and anatomical differences have been found to exist between 

 the Indo-Malayan and African species. For example, in the Indo- 

 Malayan species the vascular complex supplying the flowers is 

 derived entirely from a Single series of Strands ascending from the 

 leaf-traces, whereas in the African species the vascular complex 

 consists of a double set of Strands, the second set descending from 

 the top of the node, or from the internode above. 



The study of the microsporangium and microspore has been 

 mainly carried out on inflorescences of G. africanum. The reduced 

 number of chromosomes is probably twelve. The pollen-grain when 

 ripe contains three free nuclei. The author regards the germination 

 of the microspore and the structure of the pollen-grain as pointing 

 to a much closer degree of affinity with Welwitschia than with 

 Ephedra. Agnes Arber (Cambridge). 



Stiles, W., A note on the gametophytes of Dacvydium. (New 

 Phyt. X. p. 342—347. 4 Text-figs. 1911.) 



The material described in this note consisted of ovules ox 

 Dacvydium laxifolium and D. Colensoi from New Zealand, In the 

 latter, pollen-tubes occurred. The male gametophyte of Dacrydium 

 was found to bear a general resemblance to this structure both in 

 Podocarpus and in Phyllocladus, but the resemblance was dosest 

 between Dacrydium and Phyllocladus. The author points out that 

 the structure of the gametophytes in Dacrydium Colensoi affords 

 striking evidence in favour of the inclusion of Phyllocladus with the 

 Podocarpeae. Agnes Arbes (Cambridge). 



