76 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Means of Distribution of Alpine Plants.* — Dr. P. Vogel points out 

 what a large part is played in the Swiss Alps by the wind in the dissemi- 

 nation of plants, the very strong and variable winds being accompanied 

 by a comparative scarcity of auimal life and the almost complete dis- 

 appearance of stagnant waters. By the law, therefore, of natural selec- 

 tion, those plants which are furnished with ready means of wind disper- 

 sion, such as the possession of winged seeds, are more likely to establish 

 themselves in Alpine regions than those with no such advantage. 

 Although the carriage of seeds to much greater distances does occur, it 

 is the transport to distances between 3 and 40 kilometres that plays the 

 most important part in the dispersion of Alpine plants. A number of 

 tables are appended, exhibiting the mode of distribution of a very large 

 number of Alpine plants : by the wind, by birds, by ants or other insects, 

 by barbed bristles, by violent expulsion of the seeds, &c, &c. 



Influence of Osmotic Pressure on the Form and Structure of Plants.f 

 — From a series of experiments on tho higher plants (Phaseolus, Pisum, 

 Lupinus, Triticum, Zed), J. Beauverie concludes that the external changes 

 manifested by cultivation are connected with modifications in the ana- 

 tomical and histological structure. In the case of Phaseolus the use of 

 a concentrated Knop's solution results in the disappearance of the pith 

 from the roots, while an abundant pericyclic suber is produced at an early 

 period. The cells, reacting against the medium in order to ensure the 

 excess of osmosis necessary to maintain their integrity, absorb especially 

 certain elements which are capable of retaining the water in their 

 interior. 



Disease in Plants.J— Prof. H. Marshall Ward publishes an exhaus- 

 tive and excellent manual on this subject. The following are the 

 headings of the chapters : — The Plant and its surroundings ; The Plant 

 and its Food ; The Plant a living machine ; Metabolism ; Boots and 

 Eoot-hairs ; The Function of Eoot-hairs ; The Biology of soil ; Hybridi- 

 sation and Selection ; Phyto-pathology ; Health and Disease ; Causes of 

 Disease ; Nature of Disease ; Spreading of Disease and Epidemics ; The 

 Factors of an Epidemic ; Eemedial measures ; Variation and Disease ; 

 Symptoms of Disease ; Artificial Wounds ; Natural Wounds ; Excres- 

 cences ; Exudations and Eotting ; Necrotic Diseases ; Proliferations ; 

 Grafts ; Life and Death. A copious index is appended. 



B. CRYPTOGAMIA. 



Cryptogamia Vascularis. 



Sporange and Oophyte of Selaginella.§ — Florence M. Lyon has 

 studied the structure and development of the microsporanges and 

 megasporanges, and of the gametophyte (oophyte) in two American species 

 of Selaginella, S. apus and S. rupestris. 



In both species the sporange may frequently, if not always, be traced 

 to a single superficial cell, the archespore. The sporogenous tissue 



* Flora, Ixxxix. (1901) Erganzbd., pp. 1-137 (4 pis. and 1 fig.). 



t Comptes Rendus, exxxii. (1901) pp. 226-9. 



X Disease in Plants, London, 1901, xiv. and 291 pp. 



§ liot. Gazette, xxxii. (1899) pp. 121-41, 170-94 (5 pis.). 



