312 SUMMARY OF CURRENT RESEARCHES RELATING TO 



movement ; if a hvpha is cut in two the protoplasm streams out, but 

 the hypha is not killed ; the wound heals and the streaming recommences. 

 Light and darkness have considerable influence, and a sudden change 

 of temperature sets the protoplasm in motion. Finally he states that 

 streaming may take place in unbranched as well as in branched hypha?. 



Cultivation of a Fungus on Paraffin.* — G. Gola has followed 

 the development of an undetermined fungus on pure paraffin, vaseline, 

 etc. The brown hyph^e form a stroma on the surface, and from it 

 there arise conidiophores bearing rather large dark coloured muriform 

 conidia. Gola devoted his attention to proving that the fungus obtained 

 its nourishment from the paraffin. For this purpose he purified it and 

 sterilized it with boiling water. The developm^ent was very slow, but 

 conidia were finally produced and a stroma formed. 



General Study of Plant Pathology.! — H. Klebahn has pubhshed 

 a treatise dealing with the various aspects of plant pathology. He cites, 

 as causes of disease, adverse chemical, physical, and climatic conditions ; 

 wounds and parasitic attacks due to either plants or animals. There 

 are also obscure disturbances in the metabolism of the plants, and 

 abnormalities, deformations, and variations that arise without any 

 apparent reason. The book discusses these different subjects. 



Diseases of Plants. — An account is given by A. Fiori J of two 

 parasitic fungi that attack the needles of larch, causing them to wither 

 and fall. The young trees are especially liable to be infected, and the 

 lower parts before the upper. Both fungi are Hyphomycetes ; the first 

 described, Merla Larkis^ has somewhat dumb-bell shaped simple conidia, 

 the other, Cladosporium Laricis, has two-celled conidia. The effects pro- 

 duced are very similar in both cases. The part of the needle entered 

 by the fungus becomes reddish brown, and it falls off when the 

 mycelium reaches the base. Great injury is thus done to young trees. 



A description of clover sickness § is published by the Board of Agri- 

 culture. It is caused by a fungus, Sclerotinia trifoUorum, which attacks 

 the stalks of the clover and forms on them little black sclerotia. The 

 fungus causes the rotting of the clover and the sclerotia fall to the 

 ground. Later they produce stalked ascus fruits. Change of crop is 

 recommended as a cure. The fungus only attacks leguminous plants, 

 and will die off in time, if the host plant is not present. 



A. Fiori || gives a discription of serious damage found at the roots 

 of Acer pseudoplatanus when it was cut down. The fungus was deter- 

 mined as RoseUinia necatrix, and the results are published of his examin- 

 ation of the diseased tissues. Li a section through the part affected by 

 the fungus, he found close to the healthy wood, a first zone of reddish- 

 coloured cells caused by the near presence of the fungus, probably by 

 enzymes formed. In the areas occupied by the mycelium, fibres and 



* Bull. Soc. Bot. Ital., 1912, pp. 224-7. 



t Grundziige der Allgemeinen Phytopathologie. Berlin : Gebriider Born- 

 traeger (1912) 147 pp. (74 figs.). 



: Bull. Soc. Bot. Ital., 1912, pp. 307-12 (figs.). 



§ Journ. Board Agric, xix. (1913) pp. 928-30 (1 pi.). 



II Nuov. Giorn. Bot. Ital., xx. (1913) pp. 40-4 (1 pi.). 



