154 THE NORTH AMERICAN SLIME-MOULDS 



This genus was established by Fries in 1849 to accommodate 

 a single species of wide distribution and somewhat varying 

 habit, which is neither a Tnbifem nor yet a Cribraria and offers 

 points of resemblance to each. It is distinct in that the spo- 

 rangia, while often in single series, are yet often superimposed. 

 It resembles Tubifera in its simple sporangia, opening without 

 the aid of a net ; it is like Cribraria in the smooth ochraceous- 

 olivaceous spores and granuliferous peridium. 



I. LlNDBLADIA EFFUSA (Ehr.} RoSt. 



PLATE I., Figs. 3, 3 a, PLATE XII., Figs. I, 2. 



1818. Licea effusa Ehr., Sylv. Myc. Ber., p. 26. 

 1875. Lindbladia effusa (Ehr.) Rost. Afon., p. 223. 

 1879. Perichcena ccespitosa Peck., Rep. N.Y. Mus., p. 57. 



Sporangia minute, either closely combined and superimposed, 

 so as to form a pulvinate aethalium, or crowded together in a 

 single layer, sessile, or short stipitate ; the peridia thin, mem- 

 branous, marked by scattered plasmodic granules, often lustrous, 

 sometimes dull lead-colored or blackish, especially above ; stipe, 

 when present, very short but distinct, brown, rugulose ; hypothal- 

 lus well developed, membranous, or more or less spongiose in 

 structure ; spore-mass ochraceous, under the lens, nearly smooth, 

 almost colorless, 6-7.5 /* 



This very variable species has been well studied by Dr. Rex. 

 See Bot. Gas., XVII., p. 201. In its simpler phases it presents but 

 a single layer of sporangia generally closely crowded together, 

 sometimes free and even short stipitate ! In the more complex 

 phase the sporangia are heaped together in a pulvinate mass in 

 which the peridia appear as boundaries of minute cells. In this 

 case the outermost sporangia are often consolidated to form a 

 cortex more or less dense and shining. In any case the hypo- 

 thallus is a prominent feature ; generally laminated and of two 

 or three layers, it is in the more hemispheric sethalia very 

 much more complex, sponge-like. When thin this structure is 

 remarkable for its wide extent, 40-50 cm. ! The simpler forms 



