151 
The pycnidia are immersed in, and at’first covered by, a thin 
membranaceous subiculum which appears to be composed of 
densely interwoven pallid hyphae, adherent to the cuticle; at 
length the vertex of each shield emergés from the weft, splitting 
the cuticle and opening by a pore which gradually grows wider ; 
ultimately the shield falls away entirely, leaving a little pit. 
The cells of the subiculum are thin-walled, very indistinct and 
tightly packed, forming a pseudoparenchyma, but occasionally 
the course of the separate radiating hyphae can be discerned, 
and in that case it reminds one of the thin peridium of the 
uredo-sori of a Thecopsora. 
The mycelium appears to arise in the epidermal cells, which 
it ultimately destroys, leaving a layer of hyphae lying on the 
sclerenchymatous zone which underlies the epidermis, and 
separating easily therefrom. These hyphae leave the impression 
of the shape of their cells in the cuticle, and so that part of the 
cuticle beneath which the pycnidia are formed is seen to be 
‘“ punctulate ’’ with little roundish depressions. This gives it an 
appearance which makes a “ contextus subanhistus punctulatus 
(non vere cellulosus) ’’ like that which Saccardo falsely (in most 
cases at least) ascribes to the pycnidia of Sacidium (Syll. iii. 
625). In all the cases that I have seen such a punctulate 
anhistous pycnidium is nothing but the darkened cuticle of the 
ost, marked with the impressions of the subjacent fungous 
cells. This phenomenon can, of course, arise only where the 
fungous tissue is covered by the cuticle alone, as is usual in the 
Leptostromaceae. It may be noticed in passing, however, that 
some species of Gloeosporium, e.g. G. Potentillae, Oud. = Mars- 
sonia Potentillae, Fisch., have the pustules also covered only 
by the cuticle, so that this peculiarity is not confined to the 
Leptostromaceae and the Melampsoraceae. 
995. Phoma Ammophilae, Sacc. 
Perisporium Ammophilae, Dur. & Mont. Flor. Algér. p. 564. 
The “‘ Perisporium”’ is thus described by its authors :— 
“P. emergens globosum minutissimum myriadeum atrum 
ii . . They add “ Peri- 
maculae cinereae insidens, spori 
thecia confertissima, 40-70 » diam.” 
Jaap found on Ammophila arenaria in Schleswig-Holstein 
a fungus which he put down to this species; it had variable 
biguttulate spores about 5 xX 3p, and caespitose sporophores 
about 25 X 3p. In this sense possibly P. Ammophilae (D. & M.) 
Saee. may be upheld. 
The specimens under this name, however, available for 
examination (Roum. Fung. Gall. Exs. no. 3562 !), on leaves and 
glumes of A. arenaria, from Algeria, showed two fungi. One of 
these is = Sphaeropsis lugubris, Bomm. Rouss. & Sace. (Syll. x. 
258); the spots on which it is seated answer to the description 
of Durieu and Montagne fairly well, but it cannot be their species 
because the pycnidia are larger and not crowded. The other, 
