190 



LINNEAN SOCIETY OF LONDON. 



February 16, 1882. — F. Crisi^, Esq., Vice-President, in the 

 chair. — A paper by k. Stephen Wilson, entitled ' The Potato- 

 Disease and the theory of fungoid j)arasitism,' was read. 



March 2. — Sir John Lubbock, President, in the chair. — Col. 

 K. H. Beddome, Revv. R. P. Murray, W. H. Dallinger, R. Hooper, 

 Messrs. T. B. Chambers, C. D. Ekman, W. Fream, C. D. Labal- 

 estier, R. Vipan, were elected Fellows of the Society. — A paper 

 by Mr. Charles Knight, entitled ' Contributions to the Lichenography 

 of New South Wales,' was read; it includes the description of about 

 fifty new species. 



March 16. — Sir John Lubbock, President, in the chair. — 

 Messrs. H. M. Brewer, V. J. Chamberlain, and A. P. Withiel 

 Thomas, were elected Fellows of the Society. — Mr. Worthington 

 G. Smith called attention to certain very destructive Australian 

 fungi new to England, viz., Capnodiiim australe, fatal to Conifers, 

 especially Thuyas, and to Isaria fuciformis, a great pest to grass in 

 Kent and Sussex. The latter plant is ]3opularly supposed to 

 induce a disease similar to diphtheria, and said to be fatal to cattle. 

 Isaria frequently grows on animal substances, dead and living, as 

 on larv* and pupae of ichneumons, spiders, moths, wasps, &c. 

 Mr. Smith exhibited a bee caught alive in this country, and having 

 a profuse growth of the Isaria-condition of the Cordiceps sjjheco- 

 cephala, a West Indian form — the latter genus is closely allied to 

 Claviceps on ergot. — Two papers by Mr. Charles Darwin were 

 thereafter read, viz. : (1) 'On the Action of Carbonate of Ammonia 

 on the Roots of Certain Plants.' Many years ago the author 

 observed that, when the roots of Euphorbia Feplus were placed in a 

 solution of carbonate of ammonia, a cloud of fine granules was 

 deposited in less than a minute, and was seen travelling from cell 

 to cell. These enquiries were resumed by digging up plants of 

 this species, and carefully washing away the earth. The rootlets 

 were then examined, and sections of the thicker roots made. All 

 the cells were found to be colourless, and destitute of any solid 

 matter, the laticiferous ducts being excluded from observation. 

 These roots were left for different periods in solutions of different 

 strengths, viz., for 1 to 7 parts of the carbonate to 1000 of water; 

 they then showed a wonderful change. A solution of only 1 part 

 to 10,000 of water sufficed in twenty-four hours to produce the 

 same result. In well-developed cases the longitudinal rows of cells 

 close to the top of the root, with the exception of those forming the 

 extreme apex, were filled with brown granular matter, which 

 rendered them opaque. Long-continued immersion in water pro- 

 duced no such effect. Some rows of cells are destitute of granular 

 matter, and alternate with those that are an appearance sometimes 

 continued to the stem of the plant. These exterior cells, which 

 contain granules, do not give rise to root-hairs, these arising 

 exclusively from the colourless and apparently empty cells. The 



