Of all the Jbicidici which have come under my observatioii;
I have seen none more truly curious than tbe subject of the
present description. As well as other botanists, I had imagined
the lacerated portion of the peridium to be really filamentous,
such as that of ABf. cancellatum is said to be, and su
represented by S o w e e b y , but which I have had no opportunity
of verifying. Instead of tbis, however, I beheld under the
microscope a mass of transparent bodies, which, when in situ,
form a series of cellules. These cellules, however, appeared to
have scarcely any attachment to each other, and separated
with a touch. The consequence is, when they are examined,
some are seen adhering by a portion of the side, some by one
end, and all dropping off, as if their presence was no longer necessary
after the sporidia ceased to require protection. I have
examined this plant frequently since, and have always observed
tbe same phenomenon. That the peridium should possess such
a structure to begin with, is highly curious; but, from what I
have observed in this species, it seems probable that it is not
really cellular, according to the acceptation of the terfli in
higher orders of plants (as has been supposed), but is at present
sui generis, and requiring farther investigation.
S o w e e b y and P e k s o o n published this species in the same
year ; but S o w e e b y has. the precedence by three months, his
plate having appeared in January, and P e r s o o n ’s Synopsis
in March. As D e C a n d o l l e does not quote S o w e r b y , it
would almost appear that he had accidentally selected the same
name.
Fig. 1. Plants, natural size. Fig. 2. A young peridium, protruding itself.
Fig. 3. The fru it o f the Cratægus transversely divided, sheming the circumference
set round with the Æcidium. Fig. 4. Two peridia. Fig. 5. A peridium
removed, and exhihiting the remarlcable disintegration o f the lacerated
portwn. Fig. 6. Sporidia. Fig. 7. The transparent bodies, which form the
peridium, represented in connection, and resembling a cellular structure.
Fig. 8. The same bodies in a separate state; magnified.