218 



soundness of the practice of allowing some cuttings to dry slight- 

 ly before planting in soil is clearly supported by this interesting 

 feature of development. — Ai^yiciiUiiral Xcn's. 



RECEXT JrORK ON THE PARASITES BELONGING 

 TO THE GENUS GLOMERELLA. 



Of recent years problems in mycology have been regarded 

 from a much wider point of view than was formerly the case. 

 Particularly is this so in respect to that branch of the subject 

 known as parasitology. As an illustration of this new phase, 

 the work of Shaw in India on Rhizoctonia may be cited, and as 

 a still later example, mav be mentioned the recent work on the 

 parasites of the genus Glomerella. conducted by C. L. Shear and 

 Anna K. Wood of the United States Department of Agriculture. 

 A complete account of this latter investigation has just been 

 published as Bulletin No. 252 of the Bureau of Plant Industry, 

 and from this interesting and important paper most of the in- 

 formation in the following article has been abstracted. 



The name Glomerella is applied to the ascogenous forms of 

 Gloeosporium or Collctotrichum — form-genera of the fungi im- 

 perfecti, the parasitic nature of which is well known in the West 

 Inilies. The objects of the work under review were to study 

 the production of the ascogenous stages, and to determine the 

 habits and identity of the numerous forms of Gloeosporium and 

 Collctotrichum found upon the same hosts, and upon different 

 hosts. The method of study adopted was to observe the behavior 

 of the different forms in the moist chamber and in pure culture, 

 and to carry out a large numl)er of cross inoculation tests to find 

 out whether a so-called species of Glomerella found on one host, 

 say on the cotton i^lant, could infect another host, say the avo- 

 cado, on which a supposed different species of Glomerella was 

 regarded as being individually i)arasitic. Apart from its general 

 interest, the economic value of such an investigntion is readily 

 ai)parent. 



With particular reference to the life history of Glomerella it is 

 important to imderstand that until recently, the two principal 

 s])ore forms, conidia and ascosjiores, have been descrilied and 

 treated as distinct organisms. As is already nointed out. the 

 conidial forms are well known luider the name of Gloeosporium 

 or Colletotrichum. The essential feature of the work under re- 

 view is that ascospores, conidia and ohlamydospores or appres- 

 soria (resting-spores) are shown to be normal stages in the life- 

 history of the genus. Tliese facts greatly simplify the generic 

 classification of the forms. 



in regard to the thirty-six hosts — of which the names of some 

 arc given later — that have hitiierto been considered as being 



