DISEASES OF PLANTS. 153 



pp. 798-803, figs. 13). — A further botanical study, with illustrations of the floral 

 organs, is given of the rubber-producing tree described by the author and noted 

 above. The tree is said to belong to the ulniaceous family and to be a nevs^ 

 species of the genera Streblus de Loureiro. 



Recent analyses made of the rubber of this tree show a rubber content of 

 71.61 per cent. The results are also given of the analyses made of the rubber 

 from the creeper Bousigonia toiikincnsi!<. showing the content of rubber to be 

 77.34 per cent. 



DISEASES OF PLANTS. 



A contribution to the biology of wood-destroying' fungi, Caroline Rum- 

 r.OLD (Xatiirw. Ztschr. Forst u. Landw.. 6 ilVOS), Xo. 2, pp. 81-lJfO, pi. /, 

 figs. 25). — A contribution is given to the life history of a number of wood- 

 destroying fungi, the studies including species of Merulins, Polyporus, Ujedalea, 

 Coniophora, Agaricus, Lenzites, and Schizophyllum. Pure cultures have been 

 made of the various species, and their growth, characteristics, fruiting bodies, 

 reaction to substratum, etc., are described. 



Parasitism of Melampyrum pratense, L. Gautier (Rev. Gen. Bot., 20 (1908), 

 Xo. 230, pp. 67-8-}, figs. 21). — A study has been made of M. pratense, which is a 

 semiparasitic plant that is quite specialized in its parasitism. Its preference 

 is for the roots of forest trees, especially the beech, the roots of which are well 

 furnished with mycorrhiza. 



The germination of the seed and method of attack were studied at con- 

 siderable length. The author found that the parasitic state was quickly 

 assumed, the haustoria appearing on the rootlets even before the reserve 

 material in the seed had been used up or the cotyledons had fallen. The truly 

 nonparasitic phase of the life of this plant is very short, although not entirely 

 wanting. 



On the existence of Myxomonas betae, .1. Trzebinski {Zt.Hchr. Pflanzcnkronk., 

 n (1907), 'no. 6, pp. 321-33Jf).—A critical review is given of the work and 

 conclusions of Brzezinski, in which it is claimed that M. betw is the cause of 

 a number of diseases of the sugar beet, among them a root rot of the seedlings, 

 a dry rot of the leaves, and a hypertrophied condition of the roots. The author 

 claims that his studies, made under carefully controlled conditions, have failed 

 to substantiate the conclusions of Brzezinski, and that the reputed new 

 organism does not differ in any way from Pseudocommis vitis of Debray. 



A study of Aspergillus flavus, D. Brocq-Rousseu (Rev. Gen. Bot., 20 (1908), 

 \o. 231, pp. 102-110, pi. t). — In continuation of his studies on the alteration of 

 cereals by various molds (B. S. R., 19, p. 47), the author reports tinding 

 A. flavus very common on grains, especially on maize. A study was made of 

 this fungus, and its character of growth in various media is described, as are 

 also its morphological and biological characters. 



The author found that the fungus varied considerably in its coloration, that 

 it had the power of digesting albuminoid materials, that it secreted amylase, 

 and that it had pathogenic properties. The pathogenic properties of the fungus 

 are to be described in detail in a future publication. 



Distorted barley heads, D. von Hegyi (Ztschr. Pflanzenkrank., 17 (1907), No. 

 6, pp. 33.'i-337, figs. 2). — Descriptions ai"e given of distorted heads of barley in 

 which the awns were twisted and matted together and the heads did not fully 

 emerge from the leaf sheath. Two forms of this disease are recognized, one 

 caused by Siphonophora cerealis, the other by Helminthosporium gramineum. 



Dry rot of com, T. J. Burrill and J. T. Barrett (Illinois Sta. Circ. 117, pp. 

 3). — According to the authors, dry rot of corn is responsible for losses which in 



