DIDERMA 137 



7. DiDERMA TESTACEUM (Schrad.) Pers. 



Plate VII,, 4, 4 a, and 4 ^. 



1797. Didymium testaceum Schrad., Nov. Gen. Plant., p. 25. 



1801. Diderma testaceum Persoon, Syn., p. 167. 



1873. Chondrioderma testaceum (Schrad.) Rost., Vers., p. 13. 



1874. Diderma mariae-ivilsoni Clinton, Rep. N. Y. Mus., XXVI., p. 74. 

 1899. Diderma testaceum (Schrad.) Pers., Macbr., N. A. S., p. 99. 

 1911. Diderma testaceum Pers., List, Mycetozoa, 2nd ed., p. 106. 



Sporangia gregarious, sessile, depressed-spherical or sometimes elon- 

 gate, small, 1 mm. or less, rose-white, smooth, the outer peridium 

 crustaceous, rather thick and persistent, polished, slightly raised above 

 the inner, which is dull ashen and more or less wrinkled ; hypothallus 

 none; columella prominent, hemispherical in the typical rounded 

 forms, slightly rough, reddish or reddish alutaceous; capillitium 

 usually abundant, of slender, delicate pale or colorless threads, little 

 branched, and smooth ; spores violaceous-brown, minutely roughened, 

 8-9 IX. 



A very beautiful species occurring at the same time as the pre- 

 ceding and in similar situations. All our specimens from the west 

 are on dead leaves of oak ; some eastern gatherings are on moss. 

 Easily recognized when fresh by its delicate pink or roseate color; 

 weathered specimens are white, and might be confused with forms of 

 D. reticulatum, but the sporangia in the present species are less flat- 

 tened and only rarely in special situations run off to linear or plas- 

 modiocarpous shapes characteristic of D. reticulatum. 



Not common, although widely distributed from east to west. New 

 England, New York, New Jersey, South Carolina, Ohio, Illinois, 

 Iowa, Nebraska, California (Harkness), Washington, Oregon. 



8. Diderma niveum (Rostafinski) Macbr. 



Plate XVIII., Fig. 11 and 11 a 



1875. Chondrioderma niveum Rost, Mon., p. 170. 

 1877. Diderma albescens Phillips, Grev., V,, p. 114. 



Sporangia gregarious, scattered, or more often crowded, sessile, de- 

 pressed-spherical, sometimes ellipsoidal or elongate, white, the outer 

 peridium crustaceous, chalky, smooth and fragile, the inner distinct, 

 delicate, ochraceous ; hypothallus scant or none ; columella well devel- 

 oped, globose or hemispherical, orange-tinted or ochraceous ; capil- 



