278 Morphologie, Teratologie, Befruchtung, Cytologie. 



Upper portion of the embryonic cylinder functions as a secondary 

 suspensor. 



The definitive embryo is organized out of a portion of the cells 

 arising from the development of the embryo group of the proem- 

 bryo. It is dicotyledonous, has resin ducts in the cortex but not in 

 the wood, and is stored füll of food materials (large proteid gra- 

 nules and smaller starch grains). 



The cells of the prothallus become very large and crowded 

 with food. 



The nucellus persists and becomes a part of the testa of 

 the seed. 



The embryo continues intraseminal growth after the seeds 

 are shed. 



The second part of the paper contains an interesting discussion 

 on the poUinalion and seed structure in the Araucarians compared 

 with those in Saxegotheca, in the Cordaitales and Cycadofilicales, the 

 Cycadales, the Coniferales and the Lycopodiales. 



The structure and development of the poUen tube, processes of 

 fertilization, and the structure and development of the embryo are 

 such that it seems extremely improbable that they could have 

 derived from the analogous structures as represented in modern 

 Abietineae. 



The structure of the seed and poUinationapparatus of the Arau- 

 carians could be readily derived from the type of seeds or ovules 

 represented by such lycopods as Miadesmia. Another palaeozoic 

 seed-bearing lycopod, with which they can be compared, is Lepi- 

 docarpon. 



There is some reason to suppose that some of the Cordaitales 

 may have had ovules of the same general type as the lycopods just 

 mentioned. If so, they were probably pollinated on the scale and 

 might have given rise to modern conifers. 



It would be possible to derive modern conifers from a mesozoic 

 stock which had ovules and pollination apparatus comparable to 

 that now possessed by the Araucarians. Jongmans. 



Farr, C. H., The origin ofthe inflorescences of Xanthium. 

 (The Bot. Gazette. LIX. p. 136—148. PI. 10. 1915.) 



The pistillate and staminate heads of Xanthium commune Brit- 

 ton are associated on the same brauch. They may be contrasted 

 with respect to the following characters: position, attachment, sub- 

 tending structures, number of involucral bracts, number of vas- 

 cular bundles in the peduncle, number of flowers, and form of 

 receptacle. 



The pistillate and staminate flowers differ in degree of develop- 

 ment of pistil, corolla, and floral bract. The stamens completely 

 abort in the pistillate flower. 



The vascular System in the peduncle of the staminate head has 

 doubtless undergone reduction in the number of bundles. 



The number of stamens per staminate flower is probably now 

 undergoing reduction. 



The anthers occasionally fuse, indicating relationship to the 

 typical Compositae. 



The bur is a modified capitulum, differing from the typical 

 head of Compositae chiefly in the two depressions in the receptacle. 

 These pits originale through a temporary arrest of development, 



