ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 83 



Fungicidal Action of the Bulbs of some Orchids.* — The roots 

 of certain orcliids are continually being invaded by fungi, and the 

 late Noel Bernard endeavoured to show the means whereby they cope 

 with the invading mycelium. He selected bulbs of Ophrydeae for ex- 

 periment ; they bore roots infested by fungi, while the bulbs re- 

 main comparatively free from attack, and he grew in close proximity 

 Rhizoctonia repens, which is the fungus of Orchis morio. From the 

 results obtained he concluded that the bulbs with which he experimented 

 produced a fungicidal substance comparable to a diastase. This sub- 

 stance is easily diffusable, and is able to act in an extreme degree of 

 dilution. It does not affect all fungi to the same degree. The opinion 

 held by Bernard was, that orchids are plants that tolerate the fungus, Imt 

 prevent undue invasion. The two organisms live together in an inevit- 

 able disharmony that is, however, compatible with life and growth. 



Plant-diseases. — T. Carroll f has made an enquiry into the causes 

 that affect the spread of potato disease, Phytophthora infestans. As a 

 result of his experiments, he concludes that the tubers become inoculated 

 by falling spores, and that the leaves are mainly infected by air-borne 

 spores. 



A report % is published on the occurrence of wart-disease of potatoes 

 during last season. Where the varieties resistant to the disease, as re- 

 commended by the Board of Agriculture, have been planted there has 

 been little or no attack. The wet weather had little effect in check- 

 ing the disease where it was already established : in many cases the 

 foliage of the potato was injured. 



A disease of cucumbers, § melons, etc., due to OoUefotricIn/m oliyo- 

 chsetum is also reported on. Every part of the plant is liable to attack, 

 and seedlings are often killed in large numbers. The spots formed 

 on the leaves by the fungus are more or less circular in outline, at 

 first yellowish-green then yellowish-brown, and darker towards the edge. 

 Very young fruit is soon killed by the fungus. Advice is given as to 

 the treatment of the disease. 



J. Schorstein jj describes the appearance on pine-wood sleepers of 

 several fungi. Peniophora giyantea forms a large superficial skin on the 

 wood, but only a few millimetres depth of tissue is destroyed. Corticium 

 sanguinolentum penetrates deeper, while Polyphorus amorphus and 

 Lenzites ssepinria can entirely destroy the sleepers. 



Fr. Bubak and P. Kosaroffli" describe a series of plant-diseases from 

 Bulgaria. Corn-cobs were sent to them attacked by a fungus which had 

 prevented full growth and gave the sheaths a yellow colour. Bul)ak 

 determined the fungus as Fiisarium maydiperdum s^.n. ; the couidia 

 were rose-coloured in the mass and polymorphic. 



Two new parasitic Sphasropsidese were found on vine-leaves, belong- 



* Ann. Sci. Nat., s6r. 9, xiv. (1911) pp. 221-34. 

 t Econ. Proc. Roy. Dublin Soc, ii. (1911) p. 52. 

 J Journ. Board Agric, xviii. (1911) pp. 669-70 (1 pi.). 

 § Journ. Board Agric , xviii. (1911) pp. 670-1 (1 pi.). 



II Oesterr. Forst.-Jagdz., xxix. (.1911) p. 111. See also Pot. Centralbl., cxvii. 

 (1911) p. 486. 



t Centralbl. Bakt., xxxi. (1911) pp. 495-502 (2 pis. and 3 figs.). 



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