172 SUMMARY OF CURRENT RESEARCHES RELATING TO 



destroyed some of the trees. Vermoesen recommends the catting down 

 and destroying of diseased trees as soon as observed,and the clearing ui> 

 of all rubbish, by burning or by burying with lime. Several diseases of 

 the fruits were determined as caused by Phytophthora Faberi, Diplodia 

 cacaoicola, and by a Golletotrichum sp. 



J. R. Weir * has described two new Polyporaceas that destroy trees, 

 Fomes putearius and Trametes setosus. The former is closely allied to 

 Fomes conchatus, but it always occurs on coniferous wood, Pinusponder- 

 osa, Pseudotsuga taxifolla, etc., with a preference for larch. The rot 

 produced is similar to that caused by Trametes Pini, but the reduction of 

 lignin is on a much greater scale. The disease is abundant in the north- 

 west of Idaho in the white pine zone. 



The second fungus, Trametes setosus, is chiefly parasitic on Pinus 

 monticola, though occasionally on other Conifers. It was found in the 

 same territory as Fomes putearius and causes serious damage to fallen 

 merchantable timber in forest-fire areas. It reduces the lignin principally 

 in the spring wood, thus causing the annual rings to split. 



Mycorhiza of Calluna.f — M. Cheveley Rayner has published a 

 paper on the obligate symbiosis of Galluna with the root fungus. She 

 traces the historical knowledge of the Mycorhiza condition, and then 

 deals with the fungi that are the symbionts of the roots of higher plants. 

 The subject is attacked from various points. More especially she " con- 

 firms and extends the conclusions already reached with respect to the 

 inability of Galluna seedlings to form roots unless infected at an early 

 stage," etc. It was proved by cultures that seedlings wholly free from 

 infection and grown in a variety of sterile cultures made little advance 

 in growth, and the supply of nitrogen to the plant did not suffice to 

 replace the fungus. It was observed that in normal plants the fungus 

 appeared first as delicate outgrowths from the cells of the seed-coat. 

 The degree of infection apparent in seeds when examined is variable. 

 It was further determined that seed infection takes place not from the 

 air but from the root upwards ; all parts of the plant being permeated 

 more or less with the mycelium of the fungus. 



A fungus was successfully isolated from the ovary, and successfully 

 cultivated, inoculation of seedling cultures proving that the Mycorhiza 

 fungus had been secured. The morphological characters of the fungus 

 are described and identified as belonging to the genus Phoma. 



Other species of Ericaceas were examined, including representatives 

 of Rhododeudroideae, Arbutoideas, and Yaccinioideaa, and the author 

 has demonstrated the presence of the mycelium in the unopened flowers. 

 In some of these plants the fungus has been found in the leaves, as in 

 Galluna. A new sub-genus, Phyllophoma, has been proposed for the 

 fungus. 



*&• 



* Joum. Agric. Res., ii. (1914) pp. 163-7. See also Bull. Agric. Intell. Rome, 

 v. (1914) p. 1526 (2 pis.). 



t Ann. Bot., xxix. (1915) pp. 97-133 (1 pi. and figs.). 



