(J50 EXPERIMENT STATION EECORD. 



leaves. Tlie organism is considered liitberto imdescribed and the name Bacte- 

 rium briosianum n. sp. is given it. 



Investigations on hollyhock rust, J. Euiksson {CentU. Bakt. [etc.], 2. Abt., 

 31 (1011), Xo. l-'i, pp. V3-'J5). — The author's findings on his study of Puccinia 

 malvaeearum are compactly summarized, and support, he claims, his theory of 

 a plasma stage in which the rust is alleged to pass the winter in symbiotic 

 relations with the protoplasm of its host (E. S. R., 25, p. 850). 



The perfect stage of the rose Actinonema, F. A. Wolf {Ahs. in Science, 

 n. ser., 35 (.1912), No. 891, p. 152). — The author describes the fruiting bodies 

 of A. rosce, and includes that the development exhibited is not that of an 

 Asterella, but includes characters that necessitate a new generic grouping. 

 This study connects for the first time the conidial and ascospore stage of the 

 organism causing the black spot of roses, and the name Diplocarpon roscb is 

 given to tbe fungus. 



A bacterial disease of tropical orchids, S. HoRi (CentU. Bakt. [e/cj, 2. Abt., 

 SI (1911), No. l-Jf, pp. 85-92, figs. 2). — Tlae author gives a somewhat detailed 

 discussion of the disease called brown rot observed in greenhouses in Tokyo 

 and also on orchids grown in the open air on the Island of Oki in the Japan Sea. 

 This disease is declared to be identical with tliat called brown spot (on plants 

 of tougher texture) and to be due to a bacterium. This oi'ganism is described 

 by the author and named Bacillus cypripeiUi, although he states that it may 

 be identical with that described by V. Peglion and by him named Bacterium 

 oncidii. The disease seems to prefer the finest orchids, those having thick, 

 fleshy, succulent leaves, several species being attacked. The parasite seems to 

 enter the leaf tissue chiefly through wounds made by careless washing. The 

 chlorophyll of the infected cells collects near the center, while the bacteria 

 swarm in the surrounding cell sa]i. The infection spreads rapidly, browning, 

 rotting, and ruining the plants. 



Preventive measures recommended are the use of a soft six)nge for washing 

 soaked in a 0.1 per cent solution of sublimate, and also avoidance of excess in 

 watering, which seems to favor the disease. 



The influence of Uromyces pisi upon Euphorbia cyparissias, G. Tischleb 

 (Flora, n. ser., Jf (1911), No. 1, pp. 1-64, fiffs. 26). — An account is given of the 

 author's studies on the life relations of this fungus to its host, of which a 

 partial summary follows : 



Shoots of E. eyparissias infected with U. pisi may under favorable conditions 

 outgrow and free themselves from the injurious effects of the fungus. Early 

 production of pycuidia and secidia by the latter favors and hastens this change. 

 Ordinarily the fungus remains in the growing point of the shoot as strictly 

 intercellular mycelium, but upon the formation of vacuoles in these cells 

 haustoria strike in at once and range freely, apparently influenced by something 

 ' in the cell sap. Conditions favoring rapid growth may retard or prevent such 

 invasion of the cells. The growing point, once free of mycelium, remains so. 

 The fungus is apparently unable to grow into this region from the rhizome, 

 where it winters. 



The hyphse (but not the haustoria) grow in the vessels, by preference. Cam- 

 bium cells are not attacked. Hji^hse are to be fomid in the pith, and to a small 

 extent, in the bark. The growing mycelium dies off from below upward, and 

 disappears from the vessels, leaving the knotted haustoria in the degenerated 

 cells. Stems are very slightly affected as to form, etc. An extensive dependence 

 seems to exist between the sugar content of the tissue and the localization 

 of the fungus. Infected leaves have high osmotic pressure despite their higher 

 water content. Characteristic alterations in the leaf structure attending in- 

 fection are (1) changes in cell form, (2) readier cell division, and (3) enlarge- 



