354 EXPEEIMENT STATION RECORD. [Vol. 37 



Inver in 1907 and elsewhere later, attacking trees from 30 to 40 years old or 

 older, has recently been found in a considerable number of felled trees, the 

 fruiting body being present in many instances. The affected trees are suspected 

 to have been grown from foreign seed. 



The parasite may girdle and kill the branch, around which may form a 

 fascicle of twigs resembling a witches' broom, or it may form a patch on one 

 side, resulting in swellings and contortions and flooding the wood with resin. 

 The effects are said to resemble those produced by Peridermium pini corticola 

 (Cronartium sp.). 



The canker of the Scotch pine caused by Dasyscypha subtilissima, A. W. 

 BoBTHwicK and M. Wllson (Trans. Roy. iScot. Arbor. Soc, 2'J (lUlo), pt. 2, 

 pp. 184-187, pi. 1; abs. in Internal. Inst. Agr. {Rome}, Mo. Bui. Agr. Intel, and 

 Plant Diseases, 6 (1915), No. 11, pp. 1540, 1541). — An account is given of 

 observations made on a cankerous affection of Scotch pine as noted in the case 

 of a specimen sent from Carmichael, in Lanarkshire. The fungus D. subtilis- 

 sima, which has been previously known elsewhere as a saprophyte on P. sylvcs- 

 tris, is compared with D. icillkommii, which it resembles in some respects, nota- 

 bly in the cankers produced (in case of the latter fungus, on larch). D. sub- 

 tilUssima is known to oc-cur on several host species, and may be able to pass from 

 one to the other. Experiments have been instituted to determine whether the 

 larch can be infected by the fungus from the Scotch pine. 



The secial stage of Coleosporium ribicola, W. H. Long (Mycologia, 8 (1916), 

 No. 6, pp. 309-311). — The author has found a Peridermium on needles of pinon 

 (Pinus edulis) near which Ribcs Icptanthum was growing, and has successfully 

 inoculated the latter with jecio.^pores of the fung\is. Ho obtained a ('oU'os- 

 porium which proved to be identical in all its characters with C. ribicola. Tliis 

 is considered to prove that the fungus on pluon is the tecial stage of C. ribicola 

 and that it should be calleil P. ribicola, a technical description thereof being 

 given. 



The fungus is found early in the spring at an elevation of about 7,500 ft. 

 The coleosporial stage occurs also at much lower elevations on Kibes, sup- 

 posedly reaching these points by successive infection of Ribes plants through- 

 out the summer months by the urediniospores. 



Dothichiza populea in the United States, G. G. Hedocock and N. R. Hunt 

 (Mlici)logia. 8 (1916), No. 6", pp. 300-308, pis. 2).— Many reports having been 

 received during the spring of 1916 of a serious blight of newly transplanteil 

 black poplars (Populus nigra) and Canada poplars (/'. dcltoidcs), a study was 

 made of a fungus found, usually alone, in connection therewith. This proved 

 to be morphologically identical with /). populea. 



From earlier accounts it appears that this fungus has been imported, though 

 not very recently, from Europe. The parasite attacks the trunk, limbs, snd 

 twigs of both of these poplars, causing cankers primarily. Trees, after becom- 

 ing well established in the soil, may show marked resistance to the fungus. 

 The fungus spreads most rapidly in trees recently transplanted or in those 

 heeled in for early spring planting, but transplanted trees may become badly 

 disease<l from fresh infections between October and the following May. 



D. populea is said to be the most rapidly growing of the canker-producing 

 fungi known to the authors. Pycnospores spread the disease to adjacent trees, 

 being carried by the wind, and perhaps also, while in the sticky stage or con- 

 dition, by insects or birds. Eradication of diseased stock is the only control 

 measure recommended. 



