DIDYMIUM.] DIDYMIACE^. 95 
Mass., Mon., p. 212; Blytt, Bidr. K. Norg., Sop. iii. (1892) p. 6. 
Didymium Lihertianum de Bary, Mycetozoa, p. 124. Dulerma 
liceoides, Fv., Syst. Myc, iii., p. 107. Licea macrospora fechwem., 
in Trans. Am. Phil. Soc. (1834), p. 258. Chondrioderma hceoides 
Host., Mon., App., p. 17 ; Mass., Mon., p. 215. 
Plate XXXVII. A.— a. sporangia, x 20 ; b. capillitium attached to the 
sporangium-wall, which shows the thickened margin of the base passing into 
the membranous upper wall, x 280 ; o. portion of the crystalline crust of 
lime, X 280 ; d. delicate capillitium, x 280 ; e. spore, x 600 (England}. 
This species is removed from Chondrioderma, where it was placed 
by Rostafinski, on account of the crystalline character of the lime 
forming the outer crust of the sporangium-wall. It is to be regretted 
that there is no type of C. ealcareimi Rost. in Strassb. Herb., for the 
description in Rostafinski' s Monograph answers well for the forms 
of D. difforme with well developed capillitium ; as the latter species is 
given by Rostafinski as being almost destitute of capillitium, it is 
possible that C. calcareum is not entitled to specific rank. The type 
specimen of Chondrioderma liceoides Rost. (K. 1206) from the Schweimtz 
Herb., marked Licea macrospora by Schweinitz, is Didymium difforme ; 
the structure of the sporangium- wall and the characters of the capil- 
litium and spores are quite typical. 
Hah. On dead leaves and herbaceous stems. — Wanstead, Essex 
(L:B.M.71) ; Welshpool, Montgomery (B. M. 1062) ; France (K. 386) ; 
Germany (B. M. 507, 521, 524, 529) ; Belgium (K. 401) ; Italy 
(B. M. 627) ; India (K. 1466) ; Seychelles (K. 1467) ; Carolina (K. 1206). 
2. D. dubium Eost., Mon., p. 152 (1875). Plasmodium watery 
white, among dead leaves. Sporangia rounded or irregular plas- 
modiocarps, depressed, solitary, 1 to 12 mm. broad, 0'13 mm. 
thick; sporangium-wall of two layers, the outer consisting of 
large stellate crystals combined to form a fragile uneven crust, 
more or less attached to the delicate membranous inner layer. 
Columella none. Capillitium of profuse, rigid, erect, dark purplish- 
brown threads, anastomosing chiefly above and below, and at- 
tached at either end by colourless slender branches to the 
sporangium-wall. Spores violet-grey, spinulose or nearly smooth, 
8 to 15 /i. diam. — Cooke, Myx. Brit., fig. 167 ; Lister, in Journ. 
Bot. (1891), p. 261 ; Mass., Mon., p. 246. Didymium Listeri 
Mass., Mon., p. 244. 
Plate XXXVII., B. — a. sporangia, x 20 ; J, c, d, e. various forms of 
capillitium, and spores, x 280 ; /. fragment of sporangium- wall, showing 
the crystalline outer layer, x 280 ; g. spore, x 600 (England). 
This species is abundant at Lyme Regis, where it presents consider- 
able variation. In many gatherings the spores are nearly smooth, 
measuring 8 to 10 /x diam., in others spinulose, 12 to 15 fi. diam. ; the 
capillitium may differ from the usual form in being fiexuose with 
bead-like or irregular thickenings and with short free branches. Speci- 
mens submitted to Rostafinski are pronounced by him to be distinct 
from the original Hauenstein gathering in having smoother spores and 
more slender capillitium without thickenings ; considering the varia- 
tion mentioned above, these distinctions cannot be accepted as sufficient 
to mark the Lyme Regis form as a distinct species. 
Hah. On dead leaves. — Lyme Regis, Dorset (L:B.M.72) 
