DIDERMA 139 



Sporangia gregarious, orbicular, discoid, depressed above and often 

 umbilicate below, stipitate or sometimes sessile, the outer peridium 

 white, fragile, crustaceous, soon breaking about the margins, closely 

 applied to the inner, which is delicate, cinereous, and ruptures irregu- 

 larly; stipe about equal to the diameter of the sporangium, 1 mm., 

 rather stout, calcareous but colored, brownish or alutaceous, more or 

 less wrinkled longitudinally, the wrinkles when present forming veins 

 on the lower surface of the sporangium ; hypothallus small ; columella 

 not distinct from the thickened brownish or reddish base of the 

 sporangium ; capillitium of delicate threads, mostly simple and color- 

 less, often scanty; spores pale violaceous, nearly smooth, 8-9 fx. 



A very well marked species, easily recognized, at least when stipi- 

 tate, by its remarkable discoid or lenticular sporangia. After the 

 spore-dispersal, the stipes are long-persistent, surmounted by a pecu- 

 liar disk representing the consolidated columella, lower sporangial 

 wall, and expanded stem-top. Sessile specimens are like similar forms 

 of D. reticulatum, but in all the gatherings before us the stipitate 

 type is at hand to reveal the identity of the species. 



Rostafinski's figures, 131, 146, 149, and 150, adapted from Corda, 

 exaggerate the hypothallus, but otherwise leave nothing to be desired. 



As to synonymy, Bulliard has plainly the priority. His figure, 

 t. 446, Fig. 1, can refer to nothing else, especially reenforced as it is 

 by Sowerby, Eng. Fung., t. 12. 



Rather rare on fallen stems of herbaceous plants, but widely dis- 

 tributed, New England to Oregon and Washington. 



11. DiDERMA SAUTERI (Rost.) Macbr. 



1875. Cliondrioderma sauteri Rost., Mon., p. 181. 



1891. Cliondrioderma aculeatum Rex, Proc. Phil. Acad., p. 390. 



Sporangia scattered, gregarious, sessile, lenticular or hemispherical, 

 flattened above and sometimes concave or umbilicate below, dusky or 

 yellowish white, the outer peridium papyraceous, thin, occasionally 

 wrinkled, rupturing irregularly, remote from the inner, which is thin, 

 delicate, semi-transparent, grayish, rarely iridescent; hypothallus 

 none; columella irregular, sometimes small and hardly evident, ru- 

 gose, with spine-like processes, the persisting bases of the capillitial 



