518 Morphologie, Befruchtung, Teratologie, Cytologie. 



develope simultaneously with the rupture and probably the embryo 

 is at once independent of the ovule when water is absorbed. 



The cotyledons are cuticularised on germination; they bear 

 large water stomata and a well-marked epithem at their apices. 

 The cotyledons are perfect foliage leaves the Organisation of which 

 is complete long before they emerge from the seedcoat. The root 

 apex shows well-marked stratification in the mature seed; starch, 

 evidently statolithic in function, is found in the root cap. The spe- 

 cific differences of the plants examined are enumerated. In Sagina 

 pvociimbens a case of vegetative outgrowth of the nucellus is described 

 and in Cerastium glonieratuni two nucelli were found in one ovule. 



The author concludes that the Alsenioideae is a very well de- 

 fined group, the members being characterised by great uniformity 

 in development and structure of both the sporophyte and the repro- 

 ductive Organs. There is a developmental trend in the direction of 

 greater specialization from the Spergiileae to the Alsineae. The cha- 

 laza is the seat of the elaboration of the proteid material; the 

 medium of diffusum to the nucellus consists of the few cuticularised 

 basal nucellar cells. In the mature seed large intercellular air- 

 spaces are found in the layers of unmodified nucellar cells imme- 

 diately above the cuticularised layers. This tissue probably functions 

 as a kind of aerenchyma. The peripherial layers of the nucellus 

 are available for Solution by the cytoplasm of the embryosac and 

 provide for its increase in size; the axile rows of the nucellus re- 

 ceive and distribute the supplies of food material and in the upper 

 part elaborate the starch reserves. In the period preceding the 

 endosperm formation the food supplies are made available through 

 the agency of the suspensor. As the cotyledons are differentiated this 

 is replaced by the endosperm; the latter is differentiated into an active 

 micropylar region and an inactive peripheral portion. As the seeds 

 mature there is an approach of these sources of food supply by the 

 pressing of the micropyle against the chalaza. The Organisation of 

 the secretory cells of the endosperm is very complete; there is a 

 restriction in the formation of the endosperm to a purely digestive 

 tissue. Its function is limited to the Short period necessary for the 

 transference of the starch reserves of the perisperm to the tissues 

 of the embr5''o on germination. M. Wilson. 



Gregoire, V., Les phenomenes de l'dtape synaptique repre- 

 sentent-ils une caryocinese avortee? (La Cellule, t. XXV, 

 fasc. 1. p. 87-99. 1908.) 



D'apres l'auteur, l'interpretation proposee par R. Hertwig, con- 

 cernant la signification de l'etape synaptique, ne peut etre admise. 

 Pour V. Gregoire, l'etape synaptique constitue la preparation des 

 chromosomes heterotypiques; eile represente la premiere etape de 

 l'unique et v6ritable prophase de la cinese heterotypique. II montre 

 que l'interpretation de R. Hertwig, certainement inadmissible pour 

 la Spermatogenese et la sporogenese, ne Test pas moins pour l'ovo- 

 genfese. Henri Micheels. 



Jiekeli, C. F., Zellbildung, Encystierung und Befruchtung 

 als period^ische Ausscheidungen. (Verhandlungen und Mittei- 

 lungen des siebenbürgischen Vereins für Naturwissenschaften zu 

 Hermannstadt. LVII. Jahrg. 1907. p. 3—25. Hermannstadt 1908.) 



Verf. sucht aus der Literatur Stützen für folgende von ihm 



