86 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Parasitism of Elaphomyces granulatus.* — Tliis fungus occurs 

 iu pine-forests only, where it forms large masses ; each individual is 

 surrounded by an envelope about 4 mm. thick, formed from the 

 excessive branching of a single branchlet of the root of the pine. 

 According to Ecess, the roots branch abundantly within this envelope 

 in a dichotomous manner, and their somewhat thickened ends are 

 enveloped in a closely adherent whitish sheath, of the pseudo-paren- 

 chymatous tissue of the fungus. From this sheath mycelial filaments 

 pass on one side outwards into the soil, on the other side inwards into 

 the cortical tissue of the root, thus establishing its parasitism. The 

 hyphse are in connection with the cortex of the fructification of the 

 fungus, but are very delicate, so that they are ruptured when the 

 envelope is cut away, the fructification falling out quite smooth. 



Parasites on Tobacco. t — A tobacco plantation in the neighbour- 

 hood of Parma was observed by Professor Passerini to be subject to a 

 variegation of the leaves, which subsequently assumed the form of 

 dry, white, circular spots. This he found to be caused by two fungi, 

 of which he gives the following diagnoses, but which are probably 

 forms of some unknown spheriaceous fungus. 



Phjllosticta Tahaci. — Folia prime pallide variegata et paullatim 

 bullata, deinde areolisexaridis, candidis, irregularibus,subconfluentibus, 

 disseminata. Areola? sfepe steriles, nonnullas autem medio sordescen- 

 tes, ibique perithecia atra, punctiformia, foventia et mox lacerata. 

 Spermatia ovoidea, recta, hyalina, b. 7 mk. longa 3 mk. lata. Ad folia 

 NicotiancB Tahaci; Aug.-Sept. 



Ascochyta Nicotiance. — Perithecia in maculis exaridis irregularibus 

 subaggregata, fusca ; spermatia ovoideo-oblonga, medio septata et 

 leniter constricta, hyalina, endoplasmate granuloso. In foliis languidis, 

 prime pallide variegatis Nicotiance Tahaci ; Aug. 



On the leaves were also noticed two other fungus-parasites, Epi- 

 coccum purpurascens Ehrh. forma Tabaci, and Macrosporium commune 

 Rabh. 



Rape-disease: Pleospora Napi.J — Herr v, Bretfeld has observed 

 the great prevalence of this parasite on the rape in various parts of 

 Germany, producing very serious injury to the crop. It appears 

 especially on the siliqufe, causing them to become spotted and yellow, 

 and to burst prematurely. The author assigns the priority to Fuckel's 

 name, Pleospora Napi. It should, however, rather be called Spori- 

 dcsmium exitiosum or Pohjdesmus exitiosus ; since, although Fuckel 

 regards the latter as the conidial form of the former, he has not 

 proved their identity. The Sporidesmium which produces the disease 

 referred to, occurs abundantly in the summer on the leaves, branches, 

 and siliquae of the rape and turnip ; while the Pleospora is found 

 in the spring on the dry stubble of both plants, and is much less 



* SB. phys.-med. Soc. Erlangen, May 10, 1880. See Bot. Centralbl., i. 

 (1880) p. 1094. 



+ Atti Soc Ciitt. Ital., xxiv. (18S1) pp. 1.3-16. 



% Landwiith, 1880, No. 61. See Bot. Centralbl., 1. (1880) p. 886. 



