596 
Journal of Agricultural Research 
Vol. XXVIII, No. fr 
The practice of describing as “new species” saprophytes or omnivorous 
parasites having practically identical morphological characters simply because 
they happen to be found on different hosts or in a distant locality, is to be deplored 
as it cumbers mycological literature with a mass of doubtful names and synonyms 
and greatly impedes the progress of mycological taxonomy. Real differences in 
essential morphological characters must be the foundation for specific segrega¬ 
tion. What “real” and essential differences are can only be determined by 
careful and thorough study of a considerable amount of good material of the 
organisms in hand. Moreover when it has been shown by cross inoculations or 
studies of the fungi in pure culture that the characters upon which species have 
been segregated are such as result from host or cultural conditions and vary with 
a change of these conditions, they must be considered specifically identical. 
COMPARISON OF BOTRYOSPHAERIA RIBIS AND PHYSALOSPORA 
MALORUM 
Physalospora malorum is here used for the fungus previously referred to as 
Melanops quercuum forma vitis by Shear ( 9 ) and Physalospora cydoniae Arnaud 
by Hesler (4), the pycnidial form of which is Sphaeropsis malorum. As there 
appear to be no good specimens of this species in published American ex- 
siccati the writers will distribute what they regard as typical material of both 
stages to the principal large herbaria in the near future. The name Physalos¬ 
pora malorum is chosen as a combination of the best known names of the two- 
stages of the fungus. 
Both perithecia and pycnidia of Botryosphaeria ribis usually occur in a stroma, 
though single perithecia are often found and the size of the stromata varies, as 
has been pointed out above, with the host, and thickness of the bark. Hesler, 
in describing Physalospora cydoniae , the perfect stage of Sphaeropsis malorum ( 5 ), 
states that “the perithecia are usually scattered, standing separate from one 
another. Sometimes, however, from two to four fruit bodies are joined together, 
but no stroma has ever been observed.” The writers have not yet made a 
sufficiently extended study and comparison of these characters to form an 
opinion as to their constancy and taxonomic value. 
The paraphyses in both these species are very characteristic and have never, 
so far as we know, been correctly described or illustrated. They appear to con¬ 
sist of a tangled or anastomosing mass of septate, filamentous hyphae. In 
young perithecia the central portion is filled with a mass of pseudo-parenchyma. 
As the asci develops they push up into this mass, which becomes more or less 
filamentous at maturity, but separate paraphyses have never been observed. 
The most striking difference in the perfect stages of the two organisms is the 
size of their ascospores. See text figures 1, 2, and 3, Table I, and Plate 2. As 
is evident from the Table and figures the longer spores of B. ribis equal in length 
the shorter ones of Physalospora malorum so that from a single spore it is not 
always possible to distinguish the two fungi. The great majority of ascospores 
of P. malorum , however, are longer than the largest yet measured from B. ribis . 
and in good preparations of mature ascospores the two species are easily dis¬ 
tinguished on this basis. The same relation holds with regard to the width of 
the ascospores of the two fungi. The wider ascospores of B. ribis equal the 
narrower ascospores of P. malorum but as a whole the ascospores of P. malorum 
averaged about 3 u wider. In shape as expressed by the ratio of length to 
width the ascospores of the two fungi are very similar indeed. See figure 3 and 
Table I. 
The mode of liberation and ejection of ascospores has been observed in Physa¬ 
lospora malorum in fresh mature specimens mounted in water. The wall of the 
ascus ruptures transversely and the ascospores are ejected while still imbedded in 
a somewhat gelatinous matrix, having the same outline as the ascus and extend¬ 
ing to the base where it appears to be attached, as illustrated in Plate 2, F. and G . 
