238 SUMMARY OF CURRENT RESEARl HES RELATING TO 



in the early stages. In Eleaynus there are several differences in the 

 developments noted. In Myrica it has been determined as a species of 

 Actinomyces ; it is confined to one or two layers of cells, and is to be 

 regarded as a parasite. 



Origin of Parasitism in Fungi.* — G. Massee discusses this question 

 at some length, giving results of experiments with various forms. Ib- 

 holds that fungi normally saprophytic may be educated to prey on living 

 tissues. He took spores of the saprophytic mould Trichothecium roseum 

 along with some of the culture medium and injected them into an orchid 

 leaf, wounding the leaf to allow the egress of the fungus. It grew, and 

 the spores produced were sown in a similar way. Finally, after several 

 generations, they were sown with distilled water only on the orchid leaf, 

 when they germinated and pierced the leaf, living as true parasites on 

 the living tissue. The author holds that the earliest fungi were aquatic, 

 and that " the great wave of parasitism set in when the fungi commenced 

 to adapt themselves to dry land conditions." 



Plant-diseases in Russia. f — Helene v. Diakonoff communicates the 

 substance of a Russian paper on this subject in A. v. Jaczewski's Year- 

 book of Fungal Diseases in Cultivated Plants. On cereals the most im- 

 portant is Tilletia Tritici, causing smut in wheat. Cladosporium herbarum 

 is also reckoned a very serious disease of the grains. Among Uredineas 

 Puccinia triticina is the most widespread. Urocystis occulta and Clavi- 

 ceps purpurea attacked the rye plants ; other less important moulds are 

 also listed. Maize was attacked by Ustilago Maydis, and potato plants 

 by Phytophthora infest am ; finger-and-toe was recorded as destroying 

 cabbages in several districts. Tobacco suffered from Pythium de Barya- 

 num and hops from Sphserotheca. The diseases of orchard and garden 

 are also passed in review, and a careful account of fungicides is supplied. 



Diseases of Plants. — Griffon and Maublanc J publish some notes 

 and observations on the black stain disease of chestnuts which attacks 

 the trunks and branches. Briosi and Farnetti had diagnosed the disease 

 as due to a parasitic fungus, Melanconis jierniciosa and its conidial form 

 Goryneum. Griffon and Maublanc have also found these fungi, and 

 recognize the former as a synonym of Melanconis modonia. They are 

 not convinced that the disease is caused by them, and they suggest that 

 it may be due to some disturbance of the Mycorliiza of the roots. 



T. G. B. Osborn § gives a somewhat popular account of potato scab. 

 He describes the harmless superficial scabbing caused by abrasion of the 

 surface, often found in potatoes, grown on ashy or rough soil ; he then 

 describes more particularly corky scab, which is caused by Spongospora 

 subterranea.^ It does great damage to the crops, and has been especially 

 prevalent in Ireland. Black scab, due to Chrysophtyctis endobiotica, is 

 also described by the author. 



* Naturalist (1910) pp. 289-92. 

 t Zeitschr. Pflanzenkr., xx. (1910) pp. 460-73. 



X Coniptes Itendus, cli. (1910) pp. 1149-51. See also Bull. Soc. Mveol. France, 

 \ x vi. (1910) pp. 371-81 (3 pis.). 



§ Manchester Micr. Soc. (1910) pp. Gl-9. 



