On decorticated branches of Alnus incana. Finland.
Aethalium variable in form, suborbicular or elongated, convex,
pulvinate or depressed, 2—5 mm. broad.
I have had no opportunity of examining the present species.
I f the spores are minutely warted all over, the species may
he distinct, but clustered spores with warts all over are not
common; and remembering the numerous inaccurate descriptions
in the works of Karsten and Rostafinski in connection
with epispore marking, I am inclined to suspect the autonomy
of the present species.
Orcadella, Wing.
Sporangia with coarse stipes; sporangium wall likewise
coarse, but at the top of the sporangium replaced by a delicate
membrane which forms a more or less flattened deciduous lid.
Orcadella, Wingate, in Proc. Acad. Nat. Sci. Philada., 1889
p. 280.
The present genus is considered as the type of a new family
of the Myxogastres, described as follows by Mr. Harold Wino-ate
ill the article quoted above—■ °
This curious minute plant presents anatomical characteristics
which lead me to propose a new family of the Myxomycetes,
and which, in Dr. Rostafinski’s classification, would
come under Order IV., Anemeae, and after Family 13, Clathro-
ptychiaceae.
“ Orcadellaceae, fam. nov.
“ Sporangia without columella or capillitium, and the upper
part of the coarse sporangium wall replaced by a delicate
membrane having a defined outline.
This family seems to bridge, to a certain extent, the gap
between Rostafinski’s orders Anemeae and Heterodermeae, as”we
here have a stage between the uniform wall of Licea, Tubtdina,
&c., and the lacerate upper wall of some species of Cribrarff
where the receptacle is strongly developed and covered with
minute granulations. The epispore seems to be absolutely
without thickenings even under very high magnification.”
I am indebted to the kindness of the author for an opportunity
of examining authentic specimens, and quite agree as
to the validity of the generic characters, and also admit that
the new family founded is quite as good as most others at
present admitted in the Myxomycetes, but I am afraid that if
such trivial characters are admitted as sufficient for family
characteristics, those left for generic distinctions will be reduced
to inappreciable quantities.
Compared with allied genera, as GlathroptycMum and
Enteridium, we find that in the genus under consideration, the
apical portion of the sporangium is differentiated and eventually
disappears, whereas in the two last-named genera the
differentiation and disappearance of the sporangium is confined
to certain portions of the lateral wall; or finally, it may he
looked upon as a scattered, stipitate Tubulina with a dehiscent
apex to the sporangium.
Distrib. United S ta te s; species 1.
Orcadella opereulata. Wing. (f. 201).
Sporangia stipitate, without columella or capillitium, very
variable in form, barrel-shaped, urn-shaped, vase-shaped, ja rshaped,
ovoid or nearly globose, or all varieties appearing in
one small group; stipe slightly tapering, erect or bent, blackish,
rough and coarse from deposits of plasmodic refuse; very
variable in height. Sporangium wall likewise coarse, blackish,
containing deposits of plasmodic refuse, but at the top part
of the sporangium replaced by a delicate, yellowish, iridescent,
lustrous or vernioose membrane which forms a flat or slightly
convex circular deciduous lid, sometimes smooth, sometimes
reticulately wrinkled. Mass of spores yellowish. Individual
spores almost colourless, globose or irregularly roundish, smooth,
8—11 g in diameter.
Orcadella opereulata, Wing., Proc. Acad. Nat. Sci. Phil., 1889,
p. 280, with fig.
(Type in Herb. Acad. Nat. Sci. Philada.)
On trunks of living red-oak trees (Ouercus ruber). United
States.
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