260 Morphologie, Teratologie, Befruchtung, Cytologie. 



sunt sativum, Zea Mays and Adiantum, the thallus of Marchantia, 

 Anthoceros and Pallavicinia, the seedling of Pinus, the stem and 

 leaves of Elodea, together with certain Algae. 



The author draws the following conclusions: Leucoplasts and 

 chloroplasts are derived from granulär or rod-shaped primordia 

 which are morphologically alike and which are permanent organs 

 of the cell, with the same rank as the nucleus. These primordia 

 multiply by division. In the cells of Anthoceros , Marchantia, Pinus 

 and various higher plants, there are present in the ground-work 

 of the cytoplasm granulär and rod-shaped bodies which do not give 

 rise to either chloroplasts and leucoplasts, and to which the name 

 chondriosome is restricted. These chondriosomes multiply by divi- 

 sion and they are permanent organs of the cell. Chondriosomes, as 

 well as the primordia of leucoplasts and chloroplasts, are held by 

 the author to be concerned in the transmission of certain heredi- 

 tary characteristics. The function of the chondriosomes in the cell 

 cannot be definitely formulated at present. They are probably 

 concerned in certain processes of metabolism. 



Agnes Arber (Cambridge). 



Pearson, H. H. W., On the Morphology of the Female 

 Flower of Gnetum. (Trans. Roy. Soc. South Africa. VI. 1. p. 

 69-87. 1 pl. 1 text fig. 1917.) 



This paper is mainly concerned with a discussion of the views 

 of Lignier and Tison on the Gnetales and especially those con- 

 tained in their latest paper, „L'ovule tritegumente des Gnetum est 

 probablement un axe d'inflorescence" (Bull. Soc. Bot. Fr., 1913 (4), 

 XIII, p. 64). The writer considers that the work of these authors 

 furnishes support for his view that the female flower and the 

 „spike" of Gnetum are modifications of the same primitive structure 

 and that the primordium which normally develops into a female 

 flower may, under certain circumstances, produce a normal cone, 

 i. e. spike. The paper concludes with a comparison of the flowers 

 of the three genera. Agnes Arber (Cambridge). 



Pearson, H. H. W. and Äf. R. H. Thomson. On someStages 

 in the Life History of Gnetum. (Trans. Roy. Soc. South 

 Africa. VI. 4. p. 231—269. 6 pl. 2 Tables. 1917.) 



This paper records the result of an investigation which has 

 extended over seven years and has been concerned with seven 

 species of this genus. The authors draw attention however to the 

 incompleteness of the work and the gaps which remain to be filled. 

 More than half the paper is occupied by a discussion of the signi- 

 ficance of the phenomena observed in the Gnetalean embryo-sac 

 and the light which it throws upon the embryo-sac in other groups. 

 Owing to the length and complexity of the paper it is scarcely 

 possible to do justice to it in an abstract. It may however be stated 

 that the authors derive the Angiosperm-sac from a primitive form 

 whose essential characters are preserved in Gnetum, while the 

 Gnetum-s'dc is similarly derived from an intrasporic prothallus 

 whose fundamental characters are found in the Cycads, Ginkgo, the 

 Conifers and Ephedra. Agner Arber (Cambridge). 



