588 SUMMARY OF CURRENT RESEARCHES RELATING TO 



F. Gueguen * describes a sclerotial disease that attacked the peduncles 

 of CdlUsteppus sinensis. The sclerotia were small black isolated bodies, 

 extending from the surface to the pith. On cultivation the fungus pro- 

 duced simple conidiophores with a head of conidia united in a muci- 

 laginous drop. Occasionally the conidiophores were verticillate. 



L. Montemartini f records another case of disease due to Botrytis 

 vulgaris. The stalk and leaves of the tuberose (Polianthes tuberosa) 

 were invaded by the mycelium of the fungus. 



C. V. Piper and S. W. Fletcher $ have studied the root diseases of 

 fruit trees, and find that the rot in them is caused by Armillaria mellea 

 and an allied form. They suggest methods of cure. 



A canker of yellow birch has been demonstrated by J. B. Pollock § 

 to be due to some Nectria — probably N. coccinea. 



Report on the Blast of Rice. || — Haven Metcalf has studied this 

 disease in South Carolina. It causes wounds at the joints of the rice- 

 stalks, and is due to some fungus not determined. It has been called 

 " rotten neck," but the name is only applicable when one of the higher 

 joints is affected. It has caused very great loss in the ricefields of the 

 south. The writer gives data of disease and loss for the various districts, 

 and recommends certain forms of treatment. He gives, also, short 

 accounts of the diseases, smut, rust, damping off, blight, etc. 



Myxomonas Betas. — M. J. Brzezinski If describes at some length this 

 organism, which is a destructive parasite of beetroot, and gives rise to a 

 disease known as " dry rot." The cycle of growth of Myxomonas Betce 

 includes zoospores, lnyxaincebaa, plasmodia (vegetative), cysts (resting), 

 and spores and zoosporangia (reproductive). It has been studied within 

 the tissues of the beet, and one favourable section may contain all the 

 stages. In the vegetative forms the zoospores are extremely numerous, 

 and gradually become transformed to myxamcebae, which have a very 

 slow movement. They pass from cell to cell of the host through the 

 cell-wall, and they possess a nucleus which divides by direct division. 

 Several of these myxamoebje fuse to form the plasmodium, varying in 

 size and position ; sometimes it occupies a whole cell, at other times only 

 a corner or centre of the cell. In time the plasmodium breaks up into 

 spores, which germinate and give rise to a zoospore. The cysts are 

 formed either directly by the encystment of one of the myxanioebas, or 

 from the plasmodium ; they are small, brown, smooth, almost spherical 

 bodies. They are formed usually in those parts of the host-plant most 

 subject to drying up. When the dried up stage is passed, they give rise 

 again to myxamcebas. The zoosporangia are another form of repro- 

 duction ; they are formed from the plasmodium. 



* Comptes Rendus Soc. Biol. Paris, lx. (1906) pp. 411-13. See also Bot. Cen- 

 tralis., cii. (1906) p. 12. 



t Atti 1st. Bot. Pavia, ser. 2, xi. (1905) p. 3. See also Bot. Centralbl., cii. 

 (1906) p. 38. 



X Bull. Wash. Agric. Exper. Stat., No. lix (1903). See also Bot. Centralbl., cii. 

 (1906) p. 39. 



§ Rep. Mich. Acad. Sci., vii. (1905) pp. 55-6. See also Bot. Centralbl., cii. 

 (1906) p. 39. 



|| South Carolina Agric. Exper. Stat., Bull 121, 43 pp. 



i Bull. Inter. Acad. Sci. Cracovie, iii. (1906) pp. 139-202 (6 pis.). 



