6 BULLETIN 759, U. S. DEPAKTMENT OF AGRICULTURE. 
Sporoiuma phaeidioides Desmaz. The writer has not been able to 
discover any adequate reason for the inclusion of the other two 
names. 
SYXOXOMY OF PSEUDOPEZIZA MEDICAGIXIS. 
The first collection and description of Pseudopeziza upon a species 
of the genus Medicago were made by Madam Libert (1832, fasc. 2, 
no. 176) under the name of Phacidium medicaginls. The host was 
Medicago wUdenowii^ now known as Medicago lupuHna wUdenowii. 
Later, when Desmazieres (1841) found Pseudopeziza upon alfalfa he 
assumed that it was identical with the species described on Medicago 
wUdenowii. His assumption has not been seriously questioned. 
In 1S83 Saccardo (1883, no. 1390. 1391) transferred this species 
to the genus Pseudopeziza which Fuckel (1870) had established 
with Pseudopeziza trifolii as the type species. As soon as the two 
fungi were brought together in the same genus their similarity 
raised the question whether they were not identical. Briosi (1888) 
compared the fungi as they occurred on several species of Trifolium 
and Medicago and failing to find sufficient morphological difference 
between them to justify retaining them as distinct species advised 
that Pseudopeziza on alfalfa be called Pseudopeziza trifolii forma 
medicaginis. This usage has been followed by Eehm (1892, p. 597- 
598) and appears to have been generally accepted by mycologists, 
many of whom drop the form name altogether. Plant pathologists, 
on the other hand, have found it more convenient to retain the two 
names, though in most texts it is noted that possibly or even prob- 
ably the two species are identical. The writer believes that the fol- 
lowing pages present adequate evidence that the fungi on the two 
hosts are separate and distinct species. 
COMPARATIVE MORPHOLOGY OF THE FTXGI. 
The apothecia of both these species of Pseudopeziza arise in a deli- 
cate stroma beneath the epidermal layer of the leaf. The apothecia 
on alfalfa are usually solitary, except on overwintered leaves, where 
several clustered apothecia may develop on a stroma. On red-clover 
apothecia are sometimes clustered. The hymenial layer when first 
developed is covered with a thin stromatic stratum of small rounded 
cells, the outer layer of which may develop thick dark-colored walls. 
This stroma usually remains adherent to the epidermis when this is 
ruptured by the developing asci. 
As the hymenial layer develops, the stroma from which it arises 
becomes thicker, forming in and among the collapsing leaf cells. The 
epidermis is ruptured, the hymenium is raised above the surface of 
the leaf, and after the spores have been largely discharged and the 
hymenium has shrunken the recurved flaps of the torn epidermis 
become conspicuous around the apothecium. 
