DISEASES OF PLANTS. 1095 



vine, grown upon its own roots, is practically resistant to the California vine disease 

 and has been known to thrive and bear heavily for 15 years in the midst of thousands 

 of acres of dead and dying vineyards. 



"The Lenoir vine, as a top graft, has been known to save tender Muscat roots for 

 several years after all Muscats upon their own roots had been killed by the disease 

 throughout the surrounding region. The Lenoir vine, as a root upon which to graft 

 varieties of grapes very subject to this disease, and which are fully exposed to its 

 action, has saved tens of thousands of such tender tops in a vigorous and normal con- 

 dition for nearly or quite 5 years, or to the present date in the midst of dying vine- 

 yards, and hundreds of acres of younger vines on the same root are perfectly thrifty 

 and normal under like conditions. New varieties of grapes which have received 

 Lenoir blood through hybridizing have shown resistance to the same disease." 



The author believes that the vine disease in the Santa Clara Valley is identical 

 with the California vine disease. 



Brunissure and its physiological significance, V. Ducomet (Assoc. Franc. 

 Aram: Sci., 32 { 1904), /'/'• 697-707; abs. in Bot. Centbl, 98 (1905), No. 4, />/>. 96, 97).— 

 Brunissure i- said to be not a specific disease but a physiological accident. 



The so-called Plasmodiophora vitis and Pseudocommis vilis are not living organisms, 

 as has been claimed, but are peculiar manifestations of the cell contents due to the 

 action of various physical agents. The characteristics which have been described 

 for these alleged fungi are said to be due to the slow exosmosis of water from the 

 cytoplasm and other cell contents, permitting them to assume new forms and modi- 

 fied structures. 



Among the causes attributed for brunissure the author mentions overbearing, which 

 has already been shown by Ravaz (E. S. R., 16, p. 272) to be one of the principal 

 causes of the disease. In this case a disturbance in the equilibrium of the nutrition 

 of the plant results in the diseased appearance. 



Notes on witches' broom of cypress, F. Muth (Naluriv. Ztschr. Land- u. Forstir., 

 2 (1904). pp. 439-444, figs. 4; abs. in Bot. Centbl., 98 (1905), No. 5, />. 122).— A form 

 of witches' broom on Taxodium distichurn in Laden has been investigated, and the 

 author describes at some length the characteristic outgrowth, and he also gives the 

 results of studies on the anatomical changes observed in the twigs of the host. The 

 malformations are believed to be due to some species of Nectria, although the fruit- 

 ing bodies of the fungus have not been observed. 



Notes on the fungus occurring in the root tubercles of alders, C. G. 

 Bjorken-ueim(X/.sy7i/\ Pflanzenkrank., 14 (1904), No. 3, pp. 129-133, pi. 1). — A study is 

 given of the hyphal fungi found in the swellings of the roots of Alnus incana. The 

 fungus is described at length. 



A Botrytis disease of tulips, H. Klerahn (Ztschr. Pflanzenkrank., 14 (1904), 

 No. 1. pp. 18-36, pi. 1). — A disease of tulips which has been under observation for 

 several years is described. It seems to have been noticed first in Hamburg, and its 

 cause has been previously referred to Botvytis parasitica (E. S. R., 15, p. 273). 



The author of the present paper has made an extensive study of the disease and 

 its cause, which is thought possibly to be due to a different species of Botrytis than 

 that mentioned above. Inoculation experiments were made with the fungus on 

 hyacinth, narcissus, crocus, and other bulbs, and the results are described at length. 

 Studies were made of the fungus, pure cultures of it being grown, which were com- 

 pared with a number of species of Botrytis in an endeavor to determine the identity 

 of the tulip disease fungus. 



The diseased bulbs may be readily recognized by the occurrence of selerotia on 

 the scales, and in planting all such should be rejected. Notes are given for the 

 prevention of the disease, based largely upon the character of the selerotia and the 

 possibility of their distribution through the soil, on bulbs, implements, etc. 



