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Chondrioderma calcareum, Kost.
Sporangia sessile and mriablc in form, ovate, elongated and
curved, &o., convexo-depressed, glaucous and hyaline when
moist, qiaque and reddish or pah when dry, very fragile, at
length rupturing irregularly, leaving a b iw n impression of the
base after falling away; spores 9—11 g diameter, mixed with
a few black threads.
Ghondrioderma calcaream, Rost., in Fckl. S. Myc., 2 Nch.,
p. 74; Rost., Mon., p. 179; Saoc., Syll, 1280 ; Schroeter, p. 124.
On dry stems. Germany.
(Rostafinski’s Synonyms.)
Leocarqms calcareus. Link, Dias. I., 1. c., p. 23 (1809).
Diderma liceoides, Fr., 1. c., iii., p. 107 (1829).
Diderma chalybeum, Wein., 1. c., p. 592 (1836).
Diderma deplanatum, Fckl., S. M., p. 341; Non. Fr. (1869).
Ghondrioderma calcareum, (Lk.) in Fckl., S. M., ii., IN ch., p. 74
(1873).
Chondrioderma Stahlii, Rost.
Sporangia spherical, slightly flattened below, either dull
whitish-brown or shining and dingy brown; dehiscing by a
central pore, a long slit, or irregularly; stem brown, shining;
columella absent; threads of capillitium either simple or more
or less repeatedly bifurcate above, net combining to form a
-mtworh; spores pale violet, minutely verrueidose, 9 g diameter.
Ghondrioderma Stahlii, Rost., Mon., p. 185, f. 168; Cooke,
Brit. Myx., fig. 168; Saco., Syll., 1287.
Germany.
Didymium, Schrad. (in part).
Sporangia stipitate or sessile, wall single or double, surface
covered with lime, either in tbe form of a pulverulent stratum
of amorphous particles or crystals, or compacted into a granular
(but not porcelain-like) crust; columella present or absent;
capillitium usually well-developed, threads thin, without lime,
coloured or colourless, either radiating from the columella or
base of sporangium as simple or furcate threads, which usually
combine laterally towards the apex, or combine throughout
their lengtli to form a dense, irregular network, with tbe angles
more or less triangular and flattened. Spores lilac or violet-
brown.
Didymium, Schrad., Nov. pi. gen., p. 20. Rost., Mon., p. 160
(in p a rt); Cooke, Myx. Brit., p. 30 (in p a rt); Saco., Syll., v., 7,
pt. I., p. 376 (in p a rt); Zopf, p. 150.
The leading idea of tbe genus as defined above is, tbe wall
of the sporangium with lime outside, the thin threads of the
capillitium not containing lime, either radiating, subsimple or
bifurcating, or anastomosing irregularly throughout tbeir length
and forming a net as in the subgenus Hemididymium, the
species of which are distinguished from those of Tilmadoche
by the absence of well-defined, small, usually fusiform knots
containing granules of lime. Thickenings are not uncommon
in the capillitium of various species of Didymium, but lime is
never present.
Distrib. Temperate and tropical regions. Species 50.
Sub-Gen. Didymium.
Threads of capillitium almost simple, or bifurcating at acute
angles, here and there connected laterally, but not forming a
uniform net throughout the capillitium.
A. Sporangium stipitate.
(Sessile forms occur in D. sguamulosum and D. farinowcum.)
* Spores warted.
Didymium farinaceum, Sohrad. (figs. 29—35).
Sporangium hemispherical, usually a little depressed, more
or less umbilicate below, at first white with a continuous crust
of lime, which soon becomes broken up into wdiite glistening
granules scattered on tbe inner dark, wrinkled wall; stem
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