ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 511 



French climate. The plants showed vigorous growth after producing 

 flowers and fruit during a considerable portion of the winter. The 

 grafting operation often effects a considerable change in the characters 

 of the graft or the stock, thus enabling the grower to produce flowers or 

 fruits out of the usual season, as well as demonstrating the plasticity of 

 the species under the influence of sudden variations in its environment. 



Experiments on Grafted Plants.* — L. Daniel also contributes 

 several papers in which he describes the results of his experiments on 

 grafted shoots and plants ; his results are important from an economic 

 point of view. 



Abnormal Growths in Woody Plants. t — J. Esteva gives photo- 

 graphic representations of abnormal development and growth in the trunk 

 of sweet chestnut and poplar, and of a case of fasciation in Spartium 

 junceum. 



Reproductive. 



Development in Piperaceae4 — D. S. Johnson finds no suggestion 

 of the remarkable embryogeny described for Peperomia in other genera 

 of the order {Piper and Heckeria). The development of ovary, ovule, 

 and embryo-sac differ widely in several respects from that found in the 

 related genus Peperomia. The ovary is syncarpous and the ovule has 

 two integuments ; the archesporial cell gives rise to a tapetal cell and a 

 single megaspore, and from the latter a seven-nucleate embryo-sac arises 

 in the usual way. The antipodals and synergicls are long persistent. 

 The embryo in the ripe seed is very small, it is globular and undifferen- 

 tiated except for a very short snspensor. The endosperm nucleus of 

 Piper forms twenty or more free nuclei, and then cell-walls are formed 

 simultaneously about all of them. In HecJceria the endosperm-nuclei 

 are separated from the first by cell-walls. In both, as in Peperomia, the 

 endosperm is comparatively small in the ripe seed and contains no starch, 

 abundance of which is found in the surrounding perisperm. 



The author also studied the germination of the seeds of Peperomia 

 and Heckeria. The seed-coat is burst by the swelling of the endosperm 

 and embryo ; the endosperm protrudes as a sac which continues to 

 surround the embryo until after root and the two cotyledons are dif- 

 ferentiated. The root finally pushes out through the endosperm, but 

 the latter remains about the tips of the cotyledons and imbedded in the 

 seed till all the starch of the perisperm is absorbed. 



The striking differences in the mode of formation of the endosperm 

 in the three genera show that characters of this kind are often of no 

 value as indications of affinity. The writer still maintains the position 

 that the peculiarities in Peperomia are secondary. The case of Gunnera, 

 where Schnegg has shown that the embryo-sac contains sixteen or more 

 nuclei, and that the endosperm nucleus is formed by the fusion of eight 

 or ten of these, is probably an independent secondary development. 



The writer sees no reason to doubt that Peperomia finds its true 

 affinity among the Piperacese. 



* Trav. Sci. de l'Univ. de Eennes, i. pp. 57-63, 69-77, 99-102, 343-59, 365-9. 

 t Bol. Soc. Espaii. Hist. Nat., iii. (1903) pp. 150-2 (4 figs.). 

 t Bot. Gazette, xxxiv. (1902; pp. 322-40 (2 pie.). 



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