328 
W. B. Mercer, 
10. Systematic position of the fungus. 
From the nature of the pycnidia and spores it is evident that the 
fungus is a species of either Phyllosticta or Phoma. These two genera 
are very similar in the form of their fruits. 
According to Saccardo the distinguishing characters are: 
Phyllosticta . . . maculicola, poro pertusa, 
Phoma .non maculicola, papillata. 
Allescher (in Rabenhorsts Cryptogamenflora) divides them 
according to the substratum: 
Phyllosticta . nur Blätter bewohnend, seltener mit kleiner Papille, 
Phoma . . . auf Stengelorganen etc., mit Papille. 
In the case of fungi which are not proved parasites no great reliance 
can be placed on the substratum as a means of identification. 
Even the neck is not a very certain means of distinction, for it 
varies a great deal with different species of Phoma. In Phoma apiicola 1 ') 
it is straight, broad and tubular, set on the top of a spherical body, 
like the neck of a flask; in Phoma suspecta 2 ) it is short, tapering, and 
continuous with the main part of the wall, resembling the truncated 
“neck“ of a pear. On the other hand the apex of the pycnidium in some 
species of Phyllosticta — e. g. P. tabifica 3 ) — is drawn out so that 
the fruit body approaches very closely in shape to that of some Phomas. 
In the present case no neck is formed on most media though the 
apex may be slightly pushed out. In cultures on sterile Calla-le&i, how¬ 
ever, a short pear-like neck is present. Of the culture media tried, 
Calla- leaf is certainly the most natural, and as the pycnidia are the most 
regular here, it is probable that the presence of a neck is a normal 
character. I regard the fungus therefore, as a species of Phoma. 
Identification might be assisted by a careful comparison with all 
the species in the two genera; but their great number, and their great 
similarity in morphological characters, renders the task an unenviable one, 
while the scanty descriptions given in many cases tends to nullify the 
advantages derivable from the labour. 
There are many species in the two genera, occurring on Mono- 
cotylous plants, whose pycnidia and spores are comparable with those in 
the present case, but no species in either genus, with a similar secondary 
fruit form is mentioned in Rabenhorst. Only one species occurring on 
a member of the Araceae — Phyllosticta nitida Rob. (= Saccardo’s 
Phoma nitida ) — on dry leaves of Calamagrostis arenaria is there 
mentioned. 
It is described thus — „Fruchtgehäuse auf der Blattoberseite 
zerstreut, klein, glänzend, halbkugelig, innen weiß, von der später der 
Länge nach gespaltenen Epidermis bedeckt, mit papillenförmiger Mündung; 
Sporen fast eiförmig, 5 /a lang“. 
The description is not very complete, particularly as regards the 
colour of the neck, and the presence or absence of sterigmata. As, how- 
1) vide Klebahn 1. c. 
2) vide Massee (Diseases of Cultivated Plants and Trees 1910, p. 406). 
3) vide Rabenhorst 1. c. 
