MYROTHECIUM. 



[ 449 ] 



MYXOGASTRES. 



On Chorda lomentaria and Asperococcus 

 echinatus. Harv. Phyc. Brit. pi. 156. 



BIBL. L. c. sup. ; Harv. Brit. Mar. Alg. 

 p. 63. pi. 9 D, Hook. Journ. Bot. i. p. 300. 

 t. 138. 



MYROTHECIUM, Tode.A genus of 

 Onygenei(?) (Ascomycetous Fungi). 



M. roridum, Tode, a somewhat obscure 

 plant, with a peridium formed of slender 

 filaments, evanescent in the centre, and con- 

 taining a gelatinous mass of cylindrical 

 sporidia (?); grows on rotting plants, dried 

 fungi, &c. 



BIBL. Berk. Brit. Flor. ii. pt. 2. p. 323; 

 Fries, Summa Veg. p. 448. 



MYXOGASTRES. A family of minute 

 Gasteromycetous Fungi, of curious and in- 

 teresting structure, characterized by their 

 development from a mucilaginous matrix, 

 out of which arise sac-like dehiscent pe- 

 ridia, emitting a very remarkable, often 

 reticulated, filamentous structure, bearing 

 the spores. 



The Myxogastres grow upon bark of trees, 

 or decayed wood, or on leaves (especially 

 under certain atmospheric conditions), or on 

 the ground, and consist in infancy of a dif- 

 fluent mucilage of varied form and colour. 

 In proportion as this acquires consistence, 

 there is formed a crust common to the 

 whole mass, divided within into chambers, or a 

 number of individuals appear separate from it 

 and associated on a common thallus. In the 

 first case a single peridium is formed, which 

 may be regarded as a common peridium if 

 we consider the inner cells as partial peridia 

 soldered together, while in the second case 

 each individual has its own peridium. This 

 peridium, sessile or stalked, is composed of 

 one or more membranous, papery or crusta- 

 ceous coats; in some cases where there are two 

 coats, the outer is crustaceous and persistent, 

 or it is extremely thin and membranous, and 

 breaks up into deciduous scales. The mode 

 of dehiscence varies. Sometimes an irregular 

 opening is formed at the summit, as in Phy- 

 sarum ; sometimes the peridium opens like 

 a little box, as in Craterium ; sometimes the 

 upper half falls off, leaving a cup-shaped 

 base, as in Arcyria ; or the membrane may 

 be very delicate, and break up entirely into 

 little scales, which fall off and leave the 

 capillitium with its spores naked, as in Ste- 

 monitis. The capillitium or sporiferous 

 structure is formed of filaments, simple or 

 branched, free and loose, or anastomosing so 

 as to form a network ; in Trichia they have 

 spiral markings, and resemble the elaters of 



Hepaticse (PL 32. fig. 39). The filaments are 

 often elastic, and when the peridium bursts 

 they rise from the bottom of it, forming a 

 coloured, erect or drooping plume (Arcyria). 

 In many species there is a stalk (columella 

 or stylidium) in the centre of the capillitium. 

 The spores appear to be produced upon 

 these filaments by growing out from them in 

 the manner of basidiospores. They are 

 formed in vast numbers, and lie when com- 

 plete on the branches and in the interstices 

 of the capillitium. 



Synopsis of British Genera. 



* TRICHIACEI. Primary mucilage con- 

 joining several distinct peridia. Fila- 

 ments of the capillitium free, entwined, 

 elastic, or almost absent. 



1. LIC^EA. Peridium subpersistent, mem- 

 branous, bursting irregularly. Spores in 

 heaps, with scarcely any filaments. 



2. PERICH^ENA. Peridium persistent, 

 membranous, bursting by a circumscissile 

 slit. Filaments few, free. 



3. TRICHIA. Peridium simple, persist- 

 ent, bursting irregularly at the summit. 

 Filaments densely interwoven, elastic. 



4. ARCYRIA. Peridium simple, membra- 

 nous, splitting all round at the base, the 

 upper part very fugacious. Filaments densely 

 interwoven, elastic. 



** STEMONITEI. Primary mucilage con- 

 necting several distinct peridia. Fila- 

 ments conjoined into a network, adnate 

 or innate. 



5. CRIBRARIA. Peridium simple, mem- 

 branous, the upper part falling off. The 

 filaments adherent in the interior, at length 

 expanding into a free network above. 



6. DICTYDIUM. Peridium simple, sub- 

 globose, very delicately membranous, burst- 

 ing indeterminately, leaving the filaments 

 (innate) forming a cage-like, latticed capilli- 

 tium. 



7. STEMONITIS. Peridium simple, glo- 

 bose or cylindrical, delicately membranous, 

 finally evanescent. Filaments forming a 

 determinate capillitium, attached to a bristle- 

 like central columella, and forming a network 

 around it. 



8. DIACHEA. Peridium simple, ovate- 

 oblong, membranous, detached in fragments, 

 leaving a radiately reticulate capillitium, 

 with a floccose-grumous, pulverulent axis. 



9. ENERTHENEMA. Peridium simple, 

 globose, membranous, at length evanescent, 

 laying bare a conical columella with a cap at 



2 G 



