122 SEVENTEENTH REPORT. 



If we eiiipliasi/A' the i>yiiii(lial-\v;ill diaracter, a thing about which 

 Saccardo is silent — then our fungus may be taken from the genus 

 Apospluici'id and placed in the genus PlenoOotiius.. 



This transfer is Avarranted because of the demonstrated value of 

 the character of the pycnidial wall in associating organisms of 

 close relationships. The genus /'lioiiiopsis is an excellent example 

 of the worth of this character. In the genus Phoiiiopai'^ there are 

 known nearly tifty s])ecies and the great majority of these show 

 similar spore forms and more decisive, the great maj(»rity have 

 some member of the genus D'uijiortJic as a sexual state. A glance 

 at the genus Aposphacrin shows that the relationslii])s are ill- 

 assorted. There is in this group moie than thirty with sjtnies of 

 small size and wirii other characters: in variance from the rest of 

 the genus. One of these Apo^itluicrla saUriinnn Sacc. has been trans- 

 ferred by Diedicke to the genus Pleiiodoiiiii.^ because of its distinct 

 characters. I have compared the morphology of this species with the 

 fungus from apple, using llie same material Avliich Diedicke used 

 (Sydow, Mycotheca germanica ST) and hud close mor]»hologica! 

 agreement in the generic characters. It is worthy of note that 

 Plioina hrassicae or liiKjaiii which has about the same spore size as 

 the apple fungus is also i)laced by Diedicke in the genus Plenodo- 

 iinis. Judging by analogy, it may be that we can associate a num- 

 ber of closely related pathogenic forms which may be expected to 

 Jiave close correspondence in their sexual stage. It is therefore 

 essential that the im])ortant character take jirecedence over the 

 trivial. 



For these reasons, I have jtroposed the name PJriiodonius fiisco- 

 inariilaiis ( Sacc. I u. comb, and emended the d(^scri])tion to include 

 the characters of the ]>ycnidial wall. — April. IHl."). East Lansing. 

 Mich. 



Due to delay in pulilieation of this report, tlie new coniliiiiation was proposed in 

 the .Journal of Af;riiultural Keseareh o : 713 — 'TOO. and a l)rier suniniarv of thesi- 

 rea.sous was jiiven. 



