October 22, 1915] 



SCIENCE 



583 



means healthy RMzoctonia-iree potato plants 

 were made to reproduce both the " aerial 

 potato " condition and the " little potato " con- 

 dition, which are frequent consequences of 

 natural attacks of Rhizoctonia. These experi- 

 ments indicate that the abnormal effects re- 

 ferred to are purely secondary results of the 

 Rhizoctonia attack caused by interference with 

 the normal process of food storage in the 

 plant. 



Studies of Monilia Blight of Fruit Trees: 



G. B. Posey, Corvallis, Oregon. 



Prom blighted twigs of apricot, prune and 

 pear there was isolated by different members of 

 the staff of the department of botany and plant 

 pathology of the Oregon Agricultural College 

 during the season of 1913 a species of Monilia, 

 apparently unlike, in cultural characters, the 

 common " brown rot " fungus of the stone 

 fruits (Sclerotinia cinerea Bon.), which ia 

 abundant in Oregon. An investigation of this 

 blight-producing Monilia was undertaken. 

 Over fifty strains were isolated and a compari- 

 son made with over fifty strains of Sclerotinia 

 cinerea from Oregon and other parts of this 

 country and with four strains of Sclerotinia 

 fructigena secured from England. Culture 

 studies on a great variety of artificial media, 

 inoculations into various kinds of fruits, and 

 inoculations upon the twigs of various kinds 

 of fruit trees proved that this apparently un- 

 recognized species of Monilia is entirely dis- 

 tinct from the strains of S. cinerea and 8. 

 fructigena used for comparison. 



The investigation thus far has shown that 

 this Monilia is apparently common in the 

 Pacific Northwest. It has been found on 

 blighted blossoms, spurs and twigs, and some- 

 times on mummied fruits of pear, quince, apri- 

 cot, peach, prune, plum and cherry. It usually 

 starts in the spring as a blossom blight and 

 works back into the spurs and branches, where 

 the progress of the fungus is checked as the 

 season advances. Tender shoots are sometimes 

 attacked. Sporodochia are formed on the af- 

 fected parts during the same season and spores 

 are produced until late in the following spring. 

 No ascosporic stage of the Monilia under dis- 

 cussion has as yet been found, although 



apothecia of the common S. cinerea were col- 

 lected abundantly on mummied fruits of apple, 

 pear, prune, plum, peach, apricot and cherry. 

 The investigation will be continued. 

 A Podosporiella Disease of Germinating 

 Wheat: P. J. O'Gara, Salt Lake City, Utah. 

 On examining a weak strain of wheat in Salt 

 Lake Valley the trouble was traced back to the 

 seed, the content of the kernels of which were 

 found to have been largely consumed by a dark 

 brown, septate mycelium, which did not appear 

 on the surface. The seed coat was penetrated 

 later by the fruiting stalks of the fungus, 

 which was found to be a new species of Podo- 

 sporiella. The fungus is not considered to be 

 a true parasite, since it does not attack the 

 kernel till about the time of germination, and 

 has never been found in the growing portions 

 of the plant. The disease is found to be most 

 prevalent in volunteer wheat, and where sev- 

 eral crops had been grown with only surface 

 cultivation. 



The Utilization of Certain Pentoses and Com- 

 pounds of Pentoses hy Glomerella cingulata 

 (Stonem.) S. and v. S.: L. A. Hawkins, 

 U. S. D. A., Washington, D. C. 

 In the experiments an attempt was made to 

 determine the effect of the apple bitter-rot 

 fungus upon the pentose-containing compounds 

 of the apple fruit, the relative value of certain 

 pentoses and compounds of pentoses as sources 

 of carbon for this fungus, and the effect of an 

 aqueous extract of the fungus mycelium upon 

 xylan. It was found that the fungus increased 

 the alcohol-soluble pentosan content of the 

 apple fruit, but decreased the total pentosan 

 content. The fungus readily utilized either 

 xylose, arabinose xylan or arabin as sources 

 of carbon. The two pentoses were more favor- 

 able sources of carbon than glucose. Aqueous 

 extracts of the fungus mycelium when allowed 

 to act on xylan produced xylose. It is evident 

 that the fungus secretes an enzyme, which 

 hydrolyzes xylan to xylose. 

 Ar miliaria or Oah Fungus Disease in Cali- 

 fornia: W. T. HoRNE, University of Cali- 

 fornia, Berkeley, Cal. 



Cultures and specimens were exhibited and 

 the action of the fungus briefly described. 



