466 Anatomie. — Biologie. 



Hill, T. G. and E. de Fraine. On the Influenae of the 

 Structure of the Adult Plant upon the Seedling. (New 

 Phyt. XI. 8. p. 319—332. with 3 Diagrams and 9 Textfig. Oct. 1912.) 



The authors point out that in many instances not only the cha- 

 racteristic external morphology, but also the anatomical peculiari- 

 ties of the adult plant may be to some extent reproduced in the 

 seedling. As instances of this are cited: 



1. The intraxylary phloem in the cotyledons and hypocotyl of 

 seedlings of the Solanaceae. 



2. The anomalous hypocotylar structure of Mirabilis etc. 



3. The peculiar seedling anatomy shewn by the genus Salicornia 

 and by the family of the Cactaceae. 



The seedling anatomy of Persoonia lanceolata (N. O. Proteaceae) 

 is fully described, as it tends to still further emphasize this point. 



The Proteaceae shew a marked vegetative resemblance in some 

 cases to certain Gymnosperms, and the seedlings of some species 

 e. g. Persoonia lanceolata exhibit polycotyledony, as the resultofthe 

 Splitting of two original structures; a table is given to shew the 

 close resemblance between the ränge of Variation in the cotyledon 

 number in two species of Persoonia, compared with that in Pinus 

 sylvestris, it is considered possible that marked polycotyledony may 

 be connected with the coniferous form of xerophily. 



The anatomy of the cotyledons of P. lanceolata is described in 

 detail, and serves to emphasize still further the recemblance to the 

 Gymnosperms, more particularly on account of the presence of 

 transfusion tracheides. The origin, size, histology and distribution 

 of these elements in P. lanceolata is fully considered, and it is sug- 

 gested that they are "structures brought into being at the call of 

 physiologicai necessity". 



An account is given of the transition phenonema, which foUows 

 Van Tieghem's Type 3, and a brief analysis shews that a close 

 parallel obtains with the Coniferae in this respect also. A table 

 serves to summarise the relationship which exist between the coty- 

 ledons, poles of the root, etc. 



The authors conclude that the close resemblance of P. lanceo- 

 lata to the polycotyledonous Gymnosperms is "a striking instance 

 of homoplasy, in which the adult has influenced to a considerable 

 extent the seedling"; no phylogenetic significance is attached to it 

 by them. E. de Fraine. 



Begainot, A., Osservazioni e documenti sulla dissemi- 

 nazione a distanza. (Padova. 86 pp. 1912.) 



Le Phänomene de la dissemination en relation avec l'origine 

 des flores a donne lieu ä deux interpretations opposees, dont l'une, 

 generalement admise jadis, avait exagere le role de la dissemina- 

 tion ä distance en y voyant l'explication de l'extension des aires de 

 Vegetation et de la Constitution d'aires discontinues; l'autre, en fa- 

 veur depuis quelque temps, a rapportö l'origine des aires disconti- 

 nues ä la reduction des aires primitivement continues, en accordant 

 un röle restreint ä la dissemination qui agirait seulement ä petite 

 distance. Cette deuxieme these ne serait, selon Tauteur, pas moins 

 exageree que la premiere; l'importance de la dissemination ä di- 

 stance est demontree par des constatations directes (telles que 

 l'apparition soudaine d'esp^ces, leur diffusion rapide, la colonisation 

 de localites isolees, le repeuplement des iles, etc.), par des deduc- 



