irregular, somewhat depressed, sessile, usually close or crowded,
sometimes confluent; the hypothallus a thin membrane, pellucid or with
occasional patches of lime granules, sometimes not apparent. The wall
very thin, even or rugulose, cinereous, the thin membrane covered by a
single layer of closely-adherent granules of lime, rupturing
irregularly. Columella white, hemispheric or depressed and irregular,
the surface granulose. Capillitium of very slender, colored threads, the
extremities pellucid, more or less branched. Spores globose, minutely
warted, violaceous, 9-11 mic. in diameter. Plate XII, Fig. 46.
Growing on old wood, leaves, etc. The sporangium .3-.5 mm. in diameter,
thin and smooth or rugulose. The species superficially greatly resembles
_Physarum cinereum_.
10. DIDERMA DIFFORME, Pers. Plasmodiocarp roundish, oblong, or more or
less elongated and flexuous, scattered or seriately disposed; the
hypothallus a thin brownish membrane, or commonly not apparent. The
outer calcareous layer of the wall snow-white, thin, smooth, distinct
from the inner membrane, breaking into pieces and falling away; the
inner membrane thin, opaque and bluish or pellucid and iridescent.
Columella reduced to a thin layer of scales and granules upon the
brownish basal membrane. Capillitium scanty, consisting of short nearly
colorless threads, which are simple, or fork a time or two. Spores
globose, even, dark violaceous, 10-13 mic. in diameter.
Growing on bark, leaves, twigs, herbaceous stems, etc. Plasmodiocarp
.3-.5 mm. in thickness and variable in length, sometimes elongated
several millimeters.
11. DIDERMA RETICULATUM, Rost. Plasmodiocarp very much depressed,
roundish, oblong, much elongated and flexuous, closely crowded together
and confluent; the hypothallus a thin white granulose layer of lime,
scarcely broader than the plasmodiocarp. The outer calcareous layer of
the wall white, distinct, very fragile and easily shelling off; the
inner membrane much shrunken and withdrawn from the outer coat,
rugulose, cinereous, with a dense closely-adherent layer of granules of
lime. The columella a thin alutaceous, granulose-roughened layer,
extending along the base of the plasmodiocarp. Capillitium of threads
short and very slender, colorless, somewhat branched. Spores globose,
even, pale violaceous, 6-8 mic. in diameter. Plate XII, Fig. 47.
Growing on old wood, leaves, twigs, etc. Plasmodiocarp .5-.8 mm. in
width, much flattened and usually closely crowded. The rough calcareous
base of the plasmodiocarp might be considered as either all columella or
all hypothallus, with the upper surface leather-colored. I am indebted
to Arthur Lister, of London, for the determination of my specimens.
12. DIDERMA EFFUSUM, Schw. Plasmodiocarp very much flattened,
longitudinally creeping and reticulate or altogether widely effused;
hypothallus none. The wall very thin, smooth, white or cinereous, the
thin membrane covered by a single layer of closely-adherent granules of
lime, rupturing irregularly. The columella reduced to a thin alutaceous
layer of granules of lime, forming the base of the plasmodiocarp.
Capillitium of short colorless threads, extending from base to wall,
the extremities branched and connected together. Spores globose, even,
pale violaceous, 8-10 mic. in diameter. Plate XII, Fig. 48.
Growing on old leaves. The plasmodiocarp forms very much flattened
irregular patches from a few to several millimeters in length or extent.
I am indebted to Dr. Geo. A. Rex, of Philadelphia, for the
identification of my specimens, with those in the herbarium of
Schweinitz, under the name of _Physarum effusum_.
IV. LEPIDODERMA, DeB. Sporangium stipitate or sessile, sometimes
plasmodiocarp; the wall a thin, firm, colorless membrane, with an outer
layer of large scales consisting of bicarbonate of lime, the scales
either lying upon the wall or inclosed in lenticular cavities of the
membrane. Stipe present or absent; the columella usually conspicuous.
Capillitium of very slender threads, simple or outwardly branching at a
sharp angle, connected at the extremities. Spores globose, violaceous.
"In the present genus the carbonate of lime is present in the form of
very minute amorphous lumps until near to maturity, when it is dissolved
and reappears as bicarbonate of lime deposited in comparatively large
flakes."--_Massee._
1. LEPIDODERMA TIGRINUM, Schr. Sporangium large, much depressed,
hemispheric or lenticular, the base umbilicate, stipitate; the wall a
firm, dark colored membrane, variegated with large and small irregular
shining scales, greenish-yellow or straw color, rupturing irregularly.
Stipe stout, thick, erect, rugulose, ochraceous or ferruginous, variable
in length, expanding at the base into a thin hypothallus; the columella
brown, convex or hemispheric. Capillitium of slender, dark colored
threads, simple or sparingly branched, radiating from the columella to
the wall. Spores globose, minutely warted, dark violaceous, 10-13 mic.
in diameter.
Growing on old wood, moss, etc. Sporangium 1-1.5 mm. in diameter, the
stipe 1 mm. or less in length. This appears to be the only species of
the genus thus far discovered in this country.
EXPLANATION OF PLATE XII.
Fig. 37.--Didymium proximum, B. & C. _a._ Sporangium and stipe x 33.
_b._ Section through the columella.
Fig. 38.--Didymium eximium, Peck. _a._ Showing the rough columella of
one form. _b._ Section through the discoid columella of the very much
depressed form. Magnified by 33.
Fig. 39.--Didymium minus, Lister. _a._ Sporangium and stipe x 33. _b._
_c._ _d._ Sections through the columella showing different forms.
Fig. 40.--Didymium farinaceum, Schr. Section through the columella.
After Rostafinski.
Fig. 41.--Didymium anellus, Morgan, _a._ Growing upon a leaf x 3. _b._
Plasmodiocarp x 17.
Fig. 42.--Spumaria alba, Bull. Var. 1. didymium, sporangia x 3. Drawn
from a foreign specimen.
Fig. 43.--Spumaria alba, Bull. _a._ AEthalium natural size. _b._
Capillitium and spores as seen by a magnifying power of 500 diameters.
Fig. 44.--Diderma floriforme, Bull. Stipe and columella x 20.
Fig. 45.--Diderma crustaceum, Peck. _a._ Sporangia crowded on the thick
hypothallus, natural size. _b._ Sporangia x 11. _c._ Section through
outer coat, inner membrane, and columella.
Fig. 46.--Diderma cinereum, Morgan, _a._ Sporangia growing on a leaf x
3. _b._ Sporangia x 23. _c._ Section through the wall and columella.
Fig. 47.--Diderma reticulatum, Rost. Plasmodiocarp growing on leaf x 3.
Fig. 48.--Diderma effusum, Schw. Plasmodiocarp effused on a leaf x 3.
[Illustration: The Journal of the Cin. Soc. Natural History.
VOL. XVI. PLATE XII.]
* * * * *
Reprint from THE JOURNAL OF THE CINCINNATI SOCIETY OF NATURAL HISTORY,
August, 1896.
THE MYXOMYCETES OF THE MIAMI VALLEY, OHIO.
BY A. P. MORGAN.
Fourth Paper.
(Read May 6, 1896.)
ORDER VIII. PHYSARACEAE.
Sporangia simple and stipitate or sessile, sometimes plasmodiocarp,
rarely combined into an aethalium; the wall a thin membrane, usually
with an outer layer of minute roundish granules of lime. Stipe present
or often wanting, seldom prolonged within the sporangium as a columella.
Capillitium consisting of slender tubules, which branch repeatedly in
every direction and anastomose to form an intricate network, the
extremities attached on all sides to the wall of the sporangium; the
tubules more or less expanded at the angles of the network and inclosing
minute roundish granules of lime, these granules either aggregated into
nodules with intervening empty spaces or more rarely distributed
throughout their entire length. Spores globose, very rarely ellipsoidal,
violaceous.
This order is at once distinguished from the Didymiaceae by the presence
of the granules of lime in the capillitium.
TABLE OF GENERA OF PHYSARACEAE.
I. Tubules of the capillitium having the granules of lime in them
aggregated into roundish or angular nodules, with intervening empty
spaces.
_A. Outer surface of the sporangium destitute of lime._
1. ANGIORIDIUM. Plasmodiocarp laterally compressed, splitting regularly
into two valves.
2. CIENKOWSKIA. Plasmodiocarp terete, elongated, irregularly dehiscent.
3. LEOCARPUS. Sporangia subglobose or obovoid, stipitate or sessile.
_B. Outer surface of the sporangium invested with granules of lime._
_a. Stipe prolonged within the sporangium as a columella._
4. PHYSARELLA. Sporangium oblong, stipitate, the apex re-entrant.
5. CYTIDIUM. Sporangium globose, stipitate, the apex convex.
_b. Stipe never entering the sporangium._
6. CRATERIUM. Sporangium obovoid to cylindric, stipitate.
7. PHYSARUM. Sporangium globose, depressed globose or irregular,
stipitate or sessile.
8. FULIGO. Aethalium a compound plasmodiocarp.
II. Tubules of the capillitium with the granules of lime in them
distributed throughout their entire length.
9. BADHAMIA. Stipe not prolonged within the sporangium as a columella.
10. SCYPHIUM. Stipe entering the sporangium and prolonged within it as a
columella.
I. ANGIORIDIUM, Grev. Plasmodiocarp laterally compressed, more or less
elongated and flexuous, attached by the lower margin to the substratum,
and, at maturity, regularly dehiscent along the upper margin by a
longitudinal fissure; the wall a firm membrane, with the granules of
lime forming a reticulate layer on the inner surface. Capillitium a
loose, irregular net-work of tubules, extending from side to side, and
containing large, irregular nodules of lime. Spores globose, violaceous.
A genus readily distinguished by its laterally compressed plasmodiocarp,
splitting lengthwise by a regular fissure. The wall is a single
membrane, and there is but a single reticulate layer of lime upon it,
which is plainly on the inner surface.
1. ANGIORIDIUM SINUOSUM, Bull. Plasmodiocarp laterally compressed and
very much flattened, more or less elongated and flexuous, sometimes
confluent and branched or reticulate, without any hypothallus; the wall
a more or less thickened and brownish membrane, the inner surface coated
with a dense reticulately thickened white layer of lime, and often
studded with the white nodules. Capillitium of hyaline tubules, forming
a loose irregular net-work, with numerous broad vesicular expansions
filled with lime; the nodules white, very large, irregularly lobed, and
branched. Spores globose, very minutely warted, violaceous, 8-10 mic. in
diameter.
Growing on old leaves, sticks, mosses, etc. Plasmodiocarp commonly about
1 mm. in height and 1-5 mm. in length, but the size is variable. The
color appears to depend upon the thickening of the membrane; when it is
thin and pellucid, the color is white or cinereous from the inner layer
of lime and the contained spores; with a more thickened membrane, the
color becomes ochraceous or brownish. _Physarum bivalve_ Pers. _Physarum
sinuosum_ of Rostafinski's monograph.
II. CIENKOWSKIA, Rost. Plasmodiocarp terete, elongated, flexuous,
creeping, and reticulate, irregularly dehiscent; the wall a more or less
thickened membrane, externally naked, with the granules of lime on the
inner surface. Capillitium of slender tubules, combined into an
irregular network, attached on all sides to the wall of the sporangium,
and bearing everywhere short pointed or uncinate free branchlets; the
lime in thin transverse plates and irregular nodules. Spores globose,
violaceous.
The peculiar characteristic of this genus is the short free hooked and
pointed branchlets of the capillitium.
1. CIENKOWSKIA RETICULATA, A. & S. Plasmodiocarp more or less elongated,
curved and flexuous, simple or branched, sometimes confluent and
reticulate, breaking away first along the upper surface, leaving an
irregular margin. The wall a firm yellow membrane, with thinner hyaline
areas and with thicker yellow-brown or red-brown spots; the outer
surface without any lime, smooth, and shining; the inner surface with a
dense layer of yellow granules raised at intervals into transverse
ridges, these are connected with broad thin flat plates of lime which
traverse the capillitium, forming imperfect septa to the sporangium.
Capillitium consisting of slender yellow tubules, forming a network of
irregular meshes, with slight expansions at the angles and bearing along
the sides short pointed or uncinate free branchlets; the tubules
containing a few scattered yellow nodules of lime various in size and
shape. Spores globose, very minutely warted, violaceous, 8-10 mic. in
diameter.
Growing on old wood, bark, leaves, etc. Plasmodiocarp in veins .3-.5 mm.
in thickness, sometimes forming a net-work a centimeter or more in
extent. This curious Myxomyces seems very rare in America. I have met
with it but once. The specimen in the herbarium of Schweinitz, marked
_Physarum reticulatum_, is not this species, though it answers well
enough to the original description.
III. LEOCARPUS, Link. Sporangia subglobose or obovoid, stipitate or
sessile; the wall a more or less thickened membrane, the external
surface destitute of lime, polished and shining, irregularly dehiscent.
Stipe short, poorly developed or sometimes wanting. Capillitium of
slender tubules, forming an irregular net-work more or less expanded at
the angles; the tubules enlarging at intervals into vesicles, which
usually contain nodules of lime. Spores globose, violaceous.
A genus characterized by the form of the sporangia and the smooth and
glossy surface of the wall.
1. LEOCARPUS PSITTACINUS, Ditm. Sporangium small globose or somewhat
depressed, stipitate or subsessile; the wall a thin membrane, rugulose
and iridescent, with thicker red or yellow spots and patches, destitute
of lime. Stipe weak, erect or inclined, variable in length, the base
expanded, orange to red in color. Capillitium a dense net-work of
tubules, widely expanded at the angles and bearing numerous irregular
vesicles, various in size and form, yellow or orange to red in color.
Spores globose, even, dark violaceous, 7-9 mic. in diameter.
Growing on old wood, leaves, etc. The sporangium .5-.6 mm. in diameter,
the stipe about the same length or sometimes very short. The sporangia
are dull brownish to the naked eye, but when magnified the green,
purple, and blue metallic tints of the wall become apparent. There does
not appear to be any granules of lime either on the wall or in the
capillitium. _Physarum psittacinum_ Ditm.
2. LEOCARPUS CAESPITOSUS, Schw. Sporangium small subglobose or obovoid to
turbinate, somewhat irregular, stipitate or subsessile; the wall a
reticulately thickened and fragile membrane, yellow-brown to
greenish-yellow or olivaceous in color, externally rugulose and glossy,
the inner surface with scales and patches of lime. Stipe short and
thick, sometimes nearly obsolete, yellowish or reddish brown, darker
below, the base expanded into a small hypothallus. Capillitium a loose
irregular net-work of tubules with wide expansions at the angles; the
nodules of lime large, numerous, white or yellowish, irregular, with
acute angles and pointed lobes. Spores globose, minutely warted, dark
violaceous, 9-11 mic. in diameter.
Growing caespitosely or scattered on old wood and mosses. Sporangium
.6-.8 mm. in diameter, variable in shape, the stipe usually very short.
_Physarum caespitosum_ Schw., _North American Fungi_. My specimens, some
of them, have been referred to _Physarum citrinellum_ Peck; others to
_Physarum variabile_ Rex.
3. LEOCARPUS BRUNNEOLUS, Phillips. Sporangium large, globose or somewhat
depressed, sessile; the wall a thick yellow-brown membrane, the outer
surface naked, smooth, and polished, with a dense white inner layer of
granules of lime, dehiscing in a stellate manner, the segments becoming
reflexed. Capillitium of tubules forming a dense net-work, with wide
expansions at the angles; the nodules of lime very large, numerous,
white, angular and irregular. Spores globose, minutely warted, dark
violaceous, 8-10 mic. in diameter.
Growing on bark of oak, California (_Harkness._) Sporangium nearly 1 mm.
in diameter. _Diderma brunneolum_ Phillips. I have taken the description
from Massee's monograph.
4. LEOCARPUS FRAGILIS, Dicks. Sporangium very large, obovoid-oblong,
stipitate or subsessile; the wall a greatly thickened membrane, polished
and shining within and without, from alutaceous or pale umber to
dark-brown in color, destitute of lime. Stipe short, weak, and slender,
arising from a thin hypothallus. Capillitium of slender tubules forming
a loose network of large irregular meshes, with slight expansions at the
angles; the lime white, variable in amount, sometimes quite scanty, then
again filling large portions of the net-work with long-branched and
reticulate masses. Spores subglobose, dark violaceous, opaque, 12-15
mic. in diameter.
Growing gregariously on old wood, leaves, mosses, etc. Sporangium 1.5-2
mm. in length by 1 mm. in thickness, the stipe variable in length, but
usually much shorter than the sporangium. _Diderma vernicosum_ Pers.
IV. PHYSARELLA, Peck. Sporangium oblong, stipitate; the apex re-entrant
and confluent with the hollow columella; the wall a thin membrane
covered with small scales and minute granules of lime, at maturity torn
away at the apex and stellately splitting into a few segments. Stipe
elongated, tapering upward, entering the sporangium and prolonged to the
apex as a tubaeform columella. Capillitium distinguished by two distinct
sets of tubules; the first consisting of long, thick tubules filled with
lime, rising at regular intervals from the wall of the sporangium and
extending to the columella; the second, of very slender threads,
scarcely branched, and nearly destitute of lime, stretching between the
wall and the columella. Spores globose, violaceous.
A genus founded upon the one remarkable species, and more distinct than
any other from the typical genus of the Physaraceae. In fact, the
structure of the sporangium is unique among the Myxomycetes.
1. PHYSARELLA OBLONGA, B. & C. Sporangium oblong, the apex re-entrant
and confluent with the summit of the columella, the base obtuse or
slightly umbilicate, stipitate, cernuous. The wall of the sporangium a
firm, yellowish membrane, covered with minute granules and with
scattered, small, yellow scales of lime; after maturity the apex is torn
away more or less irregularly from the summit of the columella and the
wall splits into a few segments, which become reflexed and are
subpersistent about the base of the sporangium. Stipe long, erect or
flexuous, the apex bent or curved, red-brown, rising from a small
hypothallus, entering the sporangium and prolonged to the apex as a
hollow tubaeform columella. Capillitium of thick, spiniform tubules
filled with lime and slender, violet threads, extending between the wall
and the columella. The tubules elongated, terete, tapering gradually
from wall to columella, containing yellow granules of lime; the threads
very slender, outwardly branched a time or two, the further extremities
connected by short, lateral branches, often furnished with minute, free
branchlets, and containing a few small, fusiform nodules of lime. Spores
globose, nearly smooth, violaceous, 7-9 mic. in diameter.
Growing on old wood, bark, leaves, etc. Sporangium commonly .8-1.0 mm.
in length by .5-.6 mm. in diameter, the stipe 1-2 mm. long; the
spiniform tubules measure 150-200 x 15-20 mic.
The abnormal forms of this species which sometimes manifest themselves
are very singular; the sporangium has a tendency to dilate, becoming
funnel-form or even salver-shaped, the stipe shortening and even
disappearing. I have a large specimen which superficially resembles some
lichen, a _Physcia_, for example; the sporangia are pressed down,
flattened out, extremely irregular, and in many places confluent; the
rudimentary stipes are hidden beneath the leafy expansions. In all the
forms, however, may be uncovered the spiniform tubules mingled with the
slender threads. This is _Trichamphora oblonga_ B. & C. _Tilmadoche
oblonga_ of Rostafinski's monograph, and _Physarella mirabilis_ Peck.
V. CYTIDIUM, Morgan. Gen. nov. Sporangium globose or rarely ellipsoidal,
stipitate; the wall a thin membrane, with an external layer of minute
granules of lime, rupturing irregularly. Stipe more or less elongated,
tapering upward and entering the sporangium as a columella. Capillitium
of slender tubules, arising from the columella, repeatedly branching and
anastomosing to form a regular net-work, the extremities attached on all
sides to the wall of the sporangium, the tubules containing at intervals
nodules of lime. Spores globose, violaceous.
This genus is readily distinguished from _Physarum_ by the columella,
which gives origin to the capillitium; this feature indicates a
relationship to _Didymium_ and to _Lamproderma_.
Sec.1. EUCYTIS. Sporangium globose, the columella not reaching its center.
1. CYTIDIUM PULCHERRIMUM, B. & R. Sporangium globose, stipitate; the
wall a thin lilac-tinted membrane, with a dense closely adherent layer
of granules of lime, dark purple or wine-colored. Stipe long, erect,
dark purple to purplish black, tapering upward and entering the
sporangium as a slight obtuse columella. Capillitium of slender lilac
tinted threads, forming a dense net-work of very small meshes, with
slight expansion at the angles; the nodules of lime very small,
numerous, dark purplish or vinose in color, ellipsoidal or obtusely
angular. Spores globose, even, lilac, 7-9 mic. in diameter.
Growing on old wood. Sporangium .4-.5 mm. in diameter, the stipe two or
three times as long; the lime-nodules about the size of the spores. The
purple stain, which the sporangia leave on white paper, is made by the
granules of lime; the spores color the paper violet. _Physarum
pulcherrimum_ B. & Rav., and _P. atrorubrum_ Peck.
2. CYTIDIUM CITRINUM, Schum. Sporangium globose, the base slightly
flattened or umbilicate, stipitate; the wall a thin membrane, covered
with small scales of lime, yellow or greenish-yellow, breaking up and
falling away at maturity. Stipe stout, erect, yellow, longitudinally
rugulose, expanded at the base, tapering upward and entering the
sporangium as a short obtusely conical columella. Capillitium of slender
tubules, forming a dense net-work, with slight expansions at the angles;
the lime-nodules numerous, roundish or ellipsoidal, variable in size,
yellow. Spores globose, nearly smooth, violaceous, 7-8 mic. in diameter.
Growing on bark, leaves, mosses, etc. Sporangium .5-.6 mm. in diameter,
the stipe from once to twice this length. This, the typical species, I
have not seen in this country, but forms with the sporangium
lemon-yellow and grayish-yellow, with the stipe golden-yellow, connect
it with _C. rufipes_. It is _Physarum citrinum_ Schum. _Diderma
citrinum_ of Fries., S. M.
3. CYTIDIUM RUFIPES, A. & S. Sporangium globose, sometimes a little
depressed and the base umbilicate, stipitate; the wall a thin membrane,
covered with small scales of lime, golden-yellow to orange in color,
breaking up at maturity and falling away. Stipe variable in length,
slender, from orange or orange-red to dark red in color, sometimes
blackish below, rising from a thin hypothallus, tapering upward and
entering the sporangium as a short obtuse columella. Capillitium of
slender tubules, forming a dense net-work of very small meshes, slightly
expanded at the angles; the nodules of lime small, numerous, ellipsoidal
or obtusely angular, orange to red in color. Spores globose, nearly
smooth, violaceous, 8-10 mic. in diameter.