DIDYMIUM.] 
DIDYMIACE/E. 
101 
lime deposits; the spores in the Strassbuvg specimen ure minutely 
roughened with warts on the hemisphere of the usual number observed 
in D. efusum ; the points of difference are that in the Strassburg 
specimen the sporangia are subglobose or of irregular shape, on a 
broad base, the sporangium- wall crumpled and whitish ; in the Lyme 
Regis specimen the sporangium is a depressed plasmodiocarp, and 
resembles a Lamproderma in the iridescent wall ; but it is associated 
with other sporangia scantily furnished with lime, and also with those 
of the usual form, Chondrioderma Coolcei Rost., of which the gathering 
by Mr. Th. Brittain is represented in Strassb. Herb, and Brit. Mus. 
(B. M. 137), appears to be another form of D. effusum, differing 
from the type with sessile sporangia in the absence of lime except in 
minute spicules scattered over the sporangium-wall ; the capillitium 
is an irregular network of dull violet threads, with expansions con- 
taining nodules of lime such as are of frequent occurrence in imperfect 
developments both in this species and its allies ; the spores are spinulose, 
10 to 12 /X diam. 
Hab. On dead leaves, etc. ; common. — Lyme Regis, Dorset (L:B.M. 
77) ; Batheaston, Somerset (B. M. 37) ; Sydenham, Surrey (B. M. 1070) ; 
Welshpool, Montgomery (B. M.) ; France (K. 12) ; Germany (B. M. 
530, 550) ; Austria (B. M. 567) ; Italy (B. M. 433) ; Ceylon (B. M. 456) ; 
New Zealand (K. 1324) ; Philadelphia (L;B.M.77); S. Carolina (K. 89); 
Cuba (K. 542) ; Chili (Paris Herb.) ; Paraguay (Paris Herb.). 
8. D. crustaceum Fries, Syst. Myc, iii., p. 124 (1829), 
Plasmodium white, among dead leaves. Sporangia at first globose, 
confluent, aggregated or scattered, shortly stipitate or sessile, 0*7 
to 2 mm, diam., smooth and white from the thick fragile deci- 
duous crust of loosely compacted crystals of lime in which they 
are enclosed ; when the crust has fallen away the sporangia are 
seen to be grey, and reniform or hemispherical; sporangiiim- 
wall ; membranous, colourless, clothed with large stellate crystals 
of lime. Stalks pale buff, 0-2 to 0-4 mm. high, membranous, 
eight or ten often clustered together on an expansion of the 
membranous hypothallus, at first concealed under the crust of 
Hme enclosing the sporangia. Columella small, irregular, de- 
pressed, or not evident in the sessile forms, white or pale buff, 
charged with coarse granules of lime. Capillitium of colourless 
or pale violet branching threads 0-5 to 1 diam., with numerous 
minute fusiform thickenings. Spores purplish-grey, strongly 
spinulose, 10 to 13 fjL diam. Rost., Mon., App., p. 22. Z>, covjluens 
Rost., Mon., p, 164 (non Rost., Mon., App., p. 22) ; Mass,, Mon., 
p, 235. 
Plate XL., B.— ff. sporangia, x 20 ; J. cluster of sporangia from which 
the outer crust of lime has fallen away, arising from a common hypothallus, 
X 20; c. capillitium and spores, x 280; d. crystals of lime from the 
sporangium-wall, x 280 ; e. spore, x 600 (England). 
Closely allied to D. effusum, differing chiefly in the deciduous 
calcareous envelope of the sporangia, which is often 0-25 mm. thick, 
and m the membranous stalks. It forms a connecting link between 
D. effusum and Spumaria alba. 
Ilab On dead leaves, etc.— Lyme Regis, Dorset (L:B.M.78) ; Poland 
(Strassb, Herb.), 
