Anatomie. — Biologie. 99 



Hintikka, T. J., Zur Kenntnis der Emergenzen auf 

 den Blättern von Aristolochia Sipho L' H ö r i t. (Zeitschr. f. 

 Pflanzenkrankh. XXIII. p. 385-393. 1913.) 



Es werden die Entwickelung und der anatomische Bau der be- 

 kannten emergenzartigen Bildungen erörtert, die zuweilen an der 

 Unterseite der Blätter von Aristolochia Sipho auftreten. Dieselben 

 sind vielleicht als heteroplastische Bildungen anzusehen. Die Aetio- 

 logie ist einstweilen noch unerklärt. 



Laubert (Berlin— Zehlendorf). 



Thomson, R. B., I. On the Comparative Anatomy and 

 Affinities of the Arancarineae. (Phil. Trans. Roy. Soc. B. 204. 

 p. 1—50. 7 pl. 6 Textfig. 1913.) 



The author, as a result of a careful study of the anatomy of 

 the Araucarineae, confirms the old view that the group owes its 

 origin to the Cordaitalean aUiance. 



The ancestral presence of the leaf gap in the cone-axis and in 

 the seedling, and its occurrence in the stem, indicates the deriva- 

 tion of the group from Pteropsid stock; rather than the Lycopsid 

 as suggested by Seward. 



The resemblance to Cordaitean forms is seen in the habit, 

 structure and morphology of the leaf and in the peculiar double 

 and multiple leaf-traces in the secondary xylem. The ordinary radial 

 pitting of the tracheides and the still more primitive ray pitting of 

 tracheides is considered at some length as further evidence of Cor- 

 daitean affinity. The resin tissue of the Araucarineae is fully descri- 

 bed and the method by which the resin tissue of modern Conifers 

 could be derived from possible Cordaitean ancestors through the 

 Araucarians is considered. The simple type of the medullär)'- rays 

 is described and compared with those of the Cordaiteae. 



The question as to the nature of the "growth rings" is consi- 

 dered, but whether they are of the nature of annual rings could not 

 be determined. 



Finally, the author points out that the two species of Pityoxylon 

 formerly regarded as indicating the Carboniferous age of the Abte- 

 tineae are not authentic, hence Woodworthia (Triassic) "the first 

 Araucarian", is of greater antiquity than any of the Ahietineae at 

 present known. Thomson discusses Jeffrey's two transitional "Abie- 

 tinean- Araucarian" forms, Woodworthia and Araucariopitys , and 

 comes to the conclusion that their transitional features indicate the 

 probable origin of the Abietineae from the Araucarineae. 



E. de Fraine. 



Marloth, R., A New Mimicry Plant {Mesembrianthemum lapi- 

 diforme). (Meeting r. Soc. S. Africa. 15th Oct. 1913.) 



In summer the plant consists only of two fleshy bodies (the 

 leaves), which are half buried in the sand. Each leaf is about 1 

 inch to 1^ inches in length and width, shaped like a tetrahedron 

 with blunt edges and angles, and brownish-red in colour like the 

 angular fragments of stone among which the plant grows. It is 

 consequently most difficult to detect even in localities where its 

 occurrence is known. In spring the plant produces two flowers, one 

 at each side, which are joined to the parent plant by a very thin 

 connection. The ripe seed vessel is consequently easily detached at 



