CULTURAL IDENTIFICATION OF SPECIES. 95 



satisfactory). Examine at intervals of three days OX less, making 

 observations with the naked eye from above and below, with the 

 hand lens and with the compound microscope, using 16 nun. and 

 8 mm. or 6 nun. objectives to determine details of structure and 

 fruit formation from growing colonies. A drop of litmus solution 

 upon the margin of the colony will test acidity or alkalinity. Ex- 

 amine 1 and 2 for liquefaction, 2 and 1 for coremium and sclerotium 

 formation. Sclerotium formation will be found to call for continued 

 examination for at Least two weeks. 



Two separate keys are presented in the following pages: (1) A gen- 

 eral key to all the forms discussed in this paper, based upon cultures in 

 the media referred to above, and (2) a key to those species for which 

 presence upon a particular substratum establishes a presumption of 

 ident it \ . 



The species of most economic importance are found in key 2. 

 Key 1, however faulty, is an endeavor to analyze the data from 

 many series of comparative cultures in such a way as to simplify 

 the identification of the forms included as far as possible. If the 

 complexity of the data offered proves a barrier to identification it 

 may be hoped that it will also deter those who fail to identify species 

 clearly from usinir specific names in discussing work done with forms 

 of this genus. 



Key 1.- Analysis oi Species i\ Ci ltures upon Gelatin and Agar. 



A. Species fruiting typically by coremia (vertical and definite). 



a. < Joremia long (3 15 mm.). 



1. Conidial masses strictly terminal, olive green, fragrant. . /'. claviforme. 



l'. CTpper third of coremia fertile, conidia green P. duelauxi. 



aa. Coremia -mall: 



1. Goremia definite, densely crowded, colony orange below, 



/'. granulatum. 



2. Goremiform character indicated in cultures by clustering of 



conidiophores, definite coremia only in old cultures, becom- 

 ing large and definite upon apples P. expansum. 



AA. Species not (or rarelj ' producing coremia in culture. 



B. Species constantly producing sclerotia or ascigerous masses. 



b. Producing ascigerous masses, yellow or reddish P. luteum. 



hh. Sclerotia appearing as white masses in old cultures P. italicumfi 



bbh. Sclerotia reddish or pink, globose or i Uiptical, 500/i or Less in diameter. 



c. Conidial fructification a column: 



1. Column dense, long, Bclerotia partially buried in Bubstratum, 



/'. No. 30. 



2. Column Formed of loose chains, scler tia numerous, exposed, 



P. No. 29. 

 cc. Conidial fructification of divergenl chains: 



1. Rapid liquefier, spores glob i '■[■' /'. No. 31. 



2. Slow liquefier, spores elliptical, 3.5-4X2.5-3// /'. No. 32. 



"In its earlier development /'. italicum Wehmer will be usually thrown under the 

 head kk, on account of its habit of growth. 



