184 ENDOSPORE.E. [ARCYRIA. 



KEY TO THE SPECIES OF ARCYRIA. 



A. Spores 9 to 11 ^ diain., sporangia orange-red or buff : 



Sporangia ovoid, wall reticulated. 1. A. ferruyinea 



Sporangia clavate, wall papillose. 2. A. versicolor 



B. Spores 6 to 8 /x, diam. :- 



A. Capillitium attached to the cup 



Capillitium closely spinulose, grey, or yellowish-grey. 



3. A. albida 



Capillitium marked with cogs and half-rings ; sporangia 

 red, ovoid, or subcylindrical. 4. A. punicea 



Capillitium marked with transverse bands and minute 

 spines ; sporangia flesh-coloured, turbinate, small. 



5. A. insignis 



B. Capillitium free from the cup 



a. Network of Capillitium expanding, not drooping 



Capillitium marked with cogs and spines. 



6. A. incarnata 



Capillitium marked with cogs, spines, and three to 

 four indistinct spiral bands in addition. 



7. A. stipata 



b. Network of Capillitium much elongated, drooping 



Sporangia buff ; wall evanescent above. 



8. A. flava 



Sporangia red ; wall persistent above in shield-like 

 fragments. 9. A. (Erstedtii 



1. A. ferruginea Sauter, in Flora, xxiv., p. 316 (1841). Plas- 

 modium rose-red, in rotten wood. Total height 1 to 2 mm. 

 Sporangia ovoid, stipitate, crowded, 0'7 to 1'3 mm. high, 0*5 to 

 1 mm. broad, orange-red, or more rarely pale ochraceous; cup of 

 sporangium even, shining, funnel-shaped, or at length nearly 

 flat, marked with round-meshed reticulations on the inner side. 

 Stalk cylindrical, 0'3 to 0'8 mm. long, O05 to O15 mm. thick, 

 red, rarely white, arising from a well-developed membranous 

 hypothallus ; filled with spore-like cells. Capillitium an elastic 

 network of freely branching yellow-brown threads, 5 to 8 ^ diam., 

 diminishing to 2 to 3 ju diam. towards the base, triangular or 

 oval in section, thickened on one side with transverse bars or 

 reticulations, on the other two sides marked with a broken re- 

 ticulation or with warts, often spinulose throughout ; a few 

 sparingly branched slender threads penetrate the tube of the 

 stalk without attachments to the cup ; free ends with rounded or 

 pointed tips are not unfrequent, but often wanting. Spores pale 

 red or ochraceous, faintly and closely warted, 8 to 11 /x diam. 

 Host., Mon., p. 279 ; Cooke, Myx. Brit., p. 73, fig. 194 ; Blytt, Bidr. 



