ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 349 



is, he believes, a form of Hypomyces that never attains the full develop- 

 ment. The parasite burrows between the cells of the host, and is most 

 luxuriant in the stalk. 



J. M. Van Hook * finds that two fungi are responsible for much 

 damage to garden peas — Ascochyta Pisi and Erysiphe communis. For 

 the latter, fungicides are of value in killing the mycelium which is super- 

 ficial. As regards the former it is advisable to choose varieties of peas 

 that are able to resist the disease. Even the seeds become infected, the 

 fungus attacking the pods and growing through the seed-coats. 



Experiments t have been made with the spores of Jfacrosporium 

 Solani, which have proved it to be identical with M. tomato. This fungus 

 causes leaf-curl, and can be perpetuated by hybernating mycelium in 

 the tuber. 



Fungus of Lolium temulentum.J — E. Hannig has made a thorough 

 study of this plant and its mysterious fungus. He finds that, though it is 

 rare to gather seeds that are not infected, yet occasionally there are whole 

 plants that are free, and also occasionally some seeds are healthy though 

 borne on diseased plants. It was found impossible to distinguish the 

 two kinds of plants or seeds by their outward form : they had to be 

 examined microscopically. Fortunately the examination did not kill the 

 seeds ; they grew into healthy plants even though the larger part of their 

 endosperm had been cut away. The author has also examined the nature 

 of the poison contained in the fungus, and finds that when it is present 

 the seeds contain an alkaloid. 



Structure of a Fungus-gall. § — A. Trotter describes the anatomy of 

 a gall produced on Grevia venusta by Ustilago Grevke. He finds two 

 different tissues : the interior is sclerotic, the outer layers parenchymatous 

 and covered by a thin corky layer. Between the two tissues the gall is 

 traversed by vascular elements connected with the vascular system of the 

 host-plant. The gall begins to grow on the very young branch, and the 

 development is centrifugal round the centre of infection. 



Connection of Fungus Mycelium with the Substratum. |1 — C. Kratz 

 has examined the relations between fungus and substratum in some 

 saprophytic Pyrenomycetes. He worked with forms that live on herba- 

 ceous stems such as nettles, and on dead leaves. The structure of the plant 

 tissue influences the growth of the mycelium, which cannot penetrate 

 hard fibre, and finds its way into the woody tissue by the medullary rays. 

 The position and growth of these fungi on nettles point to the likelihood 

 of their being parasites at an early stage of their development. 



Diseases of Plants. — A report from Linhart If is to hand on the 

 result of spraying melons and cucumljers with Bordeaux mixture in order 

 to combat the disease caused by the fungus Pseudoperonosjjora cubensis. 



* Ohio Agric. Exper. Stat. Bull., clxxiii. (1906) pp. 231-49. See also Bot, 

 Centralbl., civ. (1907) pp. 337. t Kew Bull., 1906, pp. 242-5. 



X Bot. Zeit., Ixv. (1907) pp. 25-37. 



§ Malphigia, xix. (1905) pp. 156-65 (4 figs.). See also Bot. Centralbl., civ. 

 (1907) p. 212. 



II Berliner Diss. (Dresden, 1906) 28 pp., 8 figs. See also Bot. Centralbl., civ. 

 (1907) pp. 367-9. t Zeitschr. Pflanzenkr., xvi. (1907) pp. 321-2. 



