Sporangia sessile, gregarious, flattened, hemispherical; peridia simple, opening by a lid; dehiscence circumscissile, the upper part chestnut brown, the lower almost black; capillitium feebly developed, smooth, attached to the lid and usually coming away with it, bringing the brilliantly yellow spore-mass, and leaving a delicate, shining cupule adherent to the substratum; spores yellow, nearly smooth, 10–12 µ. On and under the bark of dead elms of various species.
A very handsome little species occuring rarely with us, or perhaps overlooked by virtue of its protective coloration. Found sometimes on the inner side of the bark where the latter has separated, but not yet wholly parted company with the wood. In such situations the tiny sporangia are so nearly quite the color of the moist substratum as to escape all but the closest scrutiny. The dehiscence is very remarkable, characteristic, beautiful. Black, brown, chestnut, and gold are harmoniously blended, in the opening coffers. Prior to maturity the future line of fission is plainly indicated by the difference in color.
This is clearly the species found by Batsch "ligni demortui putridi in interiore corticis pagina." Bulliard has also described and figured the species, Sphaerocarpus sessilis t. 417, Fig. V.
The capillitium is nearly smooth; the spores are only slightly roughened by minute warts.
Apparently not common. Iowa, Missouri; Black Hills, South Dakota; Canada;—Miss Currie.
4. Perichaena marginata Schweinitz.
- 1831. Perichaena marginata Schw., N. A. F., No. 2319, p. 258.
Sporangia depressed, globose, polygonal as they become approximate or crowded, hoary canescent, sessile; peridium rather thick, persistent, circumscissile in dehiscence, covered without by minute whitish calcareous (?) scales, within punctate by the imprint of the spores; hypothallus distinct, white; capillitium scant or none! Spores in mass dull yellow, by transmitted light pale, nearly smooth, 14–15 µ.
Lister, following Rostafinski, includes this form with the preceding. The differences between the two forms are, it seems to us, sufficient to make convenient their separation as by Schweinitz. Apart from the peculiar incrustation in the present species, the larger spores, and especially the peculiar white hypothallus, are distinctive. The method of dehiscence is also different. In P. corticalis the line of cleavage before spore dispersal is indicated by a definite band surrounding the sporangium. Nothing similar appears in the gray specimens of the present form, although the dehiscence is quite as certainly circumscissile. The habitat in American specimens is the outer surface of the bark, which causes the species generally, by protective coloration, to be overlooked.
Not common. Pennsylvania, Ohio, Missouri.