330 SUMMARY OF CURRENT RESEARCHES RELATING TO 



that infection of the fungus causing the disease takes effect at the bkse 

 of the large root ; the mycelium invades the cortical parenchyma after 

 penetrating the thin layer of periderm. After the death of the cambium 

 cells a browning of the whole tissues takes place. 



Melusio Turconi * has added three fungi to those already known 

 as living on Theohroma Cacao. The host-plant ■was in cultivation in 

 the botanical garden at Pavia, and it was found to be suffering from 

 some parasitic attack. The disease took the form of lighter-coloured 

 spots on the green leaves ; on these spots on the upper surface of the 

 leaves appeared the perithecia of a Pyrenomycete, determined as a new 

 species, Physalospora Theohromse. Associated with the fungus were two 

 conidial forms, Stachylidium Theohromse sp. n., and Helminthosporinm 

 Theohromse sp. n. The author does not say if he established any relation- 

 ship between these different fungi. 



A preliminary account f of disease due to species of ScUrotinia is 

 now published, later to be issued as a Leaflet No. 271 by the Board of 

 Agriculture. Sderoiinia sderotiorum is a well-known parasite of a large 

 number of cultivated plants, and in certain cases causes very great damage. 

 In potatoes it attacks the stems just above the ground and very soon 

 causes the death of the whole shoot. Tlie mycelium forms small hard 

 black bodies in the interior of the stalks, which remain on the ground 

 after the rotting of the host-tissues and in time produce apothecia and 

 spores which renew the infection. Advice is given to collect and burn 

 all diseased plants, and to avoid planting on infected soil for a space of 

 three years ; any kind of plant is liable to be attacked. 



Nechleba| has published some observations on the disease of 

 Conifers due to Armillaria melka. It is only sporadic on these trees, 

 and is apt to pass to them in mixed woods ; but if Conifers are planted 

 after deciduous trees (hosts of Armillaria) the disease may become 

 epidemic — even then it develops only vegetatively. The most dangerous 

 neighbours are beeches and winter oaks. 



Ceroid Stahel § reports a severe attack of Cacao by Marasmius per- 

 niciosus in Surinam. It grows more especially on the fruit. 



James R. Weir || writes of a new leaf- and twig-disease of Picea 

 Engelmanni, which he has determined as Herpotrichia quinqueseptata 

 sp. n., one of the Pyrenomycetes. The perithecia grow singly or in 

 groups ; the ascospores are elongate, septate, and clear brown in colour. 

 In a further communication he describes a new host-plant for Wall- 

 rothiella Arceuthohii, in Montana and Idaho, on Mistletoe. It has 

 been found also on Mistletoe in the United States. AVeir considers that 

 it may be of importance in destroying the Mistletoe. 



* Atti Reale Accad. Lincei, cccv. (1917) pp. 75-8. 

 + Journ. Board Agric, xxiii. (1917) pp. 1095-98 (2 pis.). 



X Forstwiss. Centralbl., xxxvii. (1915) pp. 384-92. See also Zeitschr. Pflan- 

 zenkr., xxvii. (1917) p. 49. 



§ Dept. Landb. Surinam, Bull No. 33 (1915) (12 pis.). See also Zeitschr. Pflan- 

 enkr., xxvii. (1917) pp. 49-50. 



y Journ. Agric. Research, iv. (1915) pp. 251-3 (1 pi.) and 369-78 (3 pis.). 



