214 Pflanzenkrankheiten. — Bacteriologie. 



Schwartz, E. J., Parasitic Root Diseases of the Juncaceae. 

 (Ann. Bot. XXIV. p. 511—521. 1 pl. July 1910.) 



The roots oi Juncus bufonius, J. articulatus dindi J . lampj'ocarpus 

 are subject to the attacks of two distinct parasites, viz. Sorophaera 

 Junci Schwartz, and Entorhisa Cypericola. Weber. 



The life history of S. Junci (a Mj'^xomycete allied to Plasniodio- 

 phord) is described in detail and it is found to correspond with that 

 of 5. Veronicae. The parasite usually gains entrance to the plant by 

 the root-hairs though direct infection through the cells of the young 

 root is also probable: it is first noticeable as an amaeba-like body. 

 The outer cells of the root only are infected, and there is no hyper- 

 trophy as in the case of 5. Veronicae. The amaebae increase in size 

 but do not coalesce to form plasmodia; the nuclei divide b}'^ mitosis. 

 Daughter nuclei may be given off by schizogony. When spores are 

 about to be formed, the amaebae become transformed into a number 

 of multi-nucleate amaebulae. The nuclei of the latter undergo two 

 ordinary mitoses, the spindle of the second being smaller than that 

 of the first (suggesting reduction). After the second division each 

 amaebula secretes a wall and becomes a uninucleate spore. The 

 spores are collected into sporophores or are loosely aggregated; and 

 they are usually enclosed by a common membrane. 



In the case of Entorhisa the roots infected iorm small tubercles, 

 the cells of the cortex being occupied b}'' the fungus. Infection 

 appears, to take place by means of the entry of conidia into the 

 roothairs. The mycelium penetrates the root and gives rise to 

 masses of spores in the cortical layers. The author conforms 

 Weber's results and agrees with him in regarding Entorhisa as 

 nearly allied to the Ustilagineae. Ä. D. Cotton (Kew). 



Alsbupg, C. L,, The formation of gluconic acid by the olive- 

 tubercle organism and the function of oxidation in some 

 microörganisms. (Proc. Soc. Exp. Biol. Med. New York. VI. 83. 

 March 15. 1909.) 



The olive-tubercle organism, Bacteriuni savastanoi Smith, when 

 grown in the presence of glucose and an excess of calcium carbo- 

 nate converts the greater part of the glucose into calcium gluconate. 

 The amount of energy liberated thereb}'' is exceedingl}^ great in 

 comparison to the weight of the organisms. This is to be explained 

 by the fact that the energy requirements of microörganisms are 

 very much greater than those of higher forms, partly because of 

 the disproportion between the body surface and the body volume 

 of microörganisms and partly because microörganisms exist in a 

 medium which is an excellent conductor of heat. Moore. 



Campbell, D. H.. The prothallium and embryo of Danaea. 

 (Rep. brit. Assoc. Advanc. Sei. Winnipeg, Section K. p. 664 — 665. 

 1909.) 



The prothallia of Danaea Jenmani, Underw., D. elliptica, Sm., 

 and D. jamaicensis are much larger and more elongated than those 

 of D. simplicifolia described hy Brebner. In many cases a ventral 

 canal -cell could not be made out. The hypobasal cell of the embryo 

 gives rise only to 1 — 2-celled suspensor; the epibasal cell divides 

 into quadrants; of these the two lower form the foot, the upper 



