152 
not seated on grey spots, is = Phoma nitida, Rob. (see next 
species, no. 997, and fig. 8b), and if not identical with that of 
Jaap, of which no specimens have been seen, seems at any rate 
to be very similar to it; in that case they probably both belong 
to Leptothyrium. The question cannot be decided until better 
specimens*are ‘available. 
997. Phoma nitida, Hob. 
LEPTOTHYRIUM NITIDUM, Grove. 
The specimen examined (Desm. Crypt. Fr. sér. 2, no. 355 !), 
on dry stems of Calamagrostis arenaria, has the spores of a 
Phoma, but as the pycnidium is very incomplete it should be 
placed in another genus. It has a thin dark pycnidial layer above, 
and a much softer and paler stratum below. Spores ovoid or 
ellipsoid, vacuolate in the middle, i.e, with the protoplasm 
retracted to each extremity, 3-5 x 2-2-5; sporophores 
crowded, subulate, very variable in length, averaging 10-12 yu 
long, often swollen below, i.e., more or less ampulliform. (Fig. 8b.) 
Each pycnidium forms a little convex, almost hemispherical, 
brownish-black and shining pustule, surrounded by a narrow 
halo which shades off gradually and is formed by brown hyphae. 
It is not a Phomopsis, and certainly not a Phoma, though its 
pycnidium seems to resemble that of Phoma Cookei, Pirotta = 
P. Vitis, Cooke, non Bon. Probably both these should be 
placed in the Leptostromaceae. 
SPECIES PROBABLY TO BE LEFT IN PHOMA. 
915. Phoma Siliquastrum, Desm. 
Desmaziéres’ own specimen (Crypt. Fr. sér. 1, no. 1874! 
possesses subcylindrical spores very similar to those of Phoma 
oleracea, Sacc., but the pycnidia are smaller and less black, 
approaching -more to the texture of a Phyllosticta. They are 
intermediate between those of P. oleracea and those of P. exigua, 
Desm. on Linum, but do not exactly agree with either. The 
spores measure about 5 x ly or less; the pycnidia occupy 
small olivaceous-brown patches, such as neither of the other 
two mentioned possesses. 
On account of the spores they could not be referred to Phoma 
nebulosa (Pers.) Mont., as the patches of hyphae suggest, but 
there is evidence that the olivaceous crusts of such fungi, formed 
of brown hyphae creeping beneath the surface, are not always 
connected with the pycnidia. I have a specimen of P. nebulosa, 
(Pers.), on stems of Angelica, which illustrates this point most 
convincingly; the young pycnidia, surrounded by hyphae,’ but 
without spores, being more like Phyllosticta, while the mature 
ones, not surrounded by hyphae and full of spores, are those of 
a typical Phoma. The conclusion is that P. Siliquastrum, 
Desm. is only an accidental form of P. oleracea, Sacc., for the 
spores are the most persistent character of any species. 
