PYRKNIBIUM.] 



PYREXIDEI. 



81 



for the geuu3 Ohnjzinn, Avitb its 



Tribe III. PYRENIDIEI Nyl. ex Crotnb. Joura. Bot. 1874, 

 p. 337 : Mora, 1875, p. 103. 



Thallus maculate, radiately appresscd ; cortical layer distinct ; 

 gonimic granules moniliformly coherent. Apothecia pyrenoid ; 

 spores 4nae, septate, brown ; paraphyses scarcely any. Spernio- 

 gones unknown. 



A singular tribe, bolding amongst the Collemacei an analogous place 

 to the Pyrenodei amongst tiie Lichenacei. lu this respect the family 

 very appropriately closes with it; 

 pyrenocarpous apothecia, is now 

 known to be entirely parasitic, and 

 must be removed. The Pi/reiiidiei 

 consist of a single genus with a sin- 

 gle species ; further research may 

 bring others to light. 



19. PYRENIDIUMXyLElora. 

 1865, p. 210.— Thallus" minute, 

 stellato-divided, fibrillose, the 

 cortical layer cellular, distinct. 

 Apothecia innate, scarcely promi- 

 neut ; spores oblon go-ellipsoid, 3- 

 septate, brownish ; paraphyses 

 slender, few or obsolete ; hyme- 

 nial gelatine not tinged with 

 iodine. 



Having regard only to the thal- 

 lus, this genus might be supposed 

 to be allied to Lepioyium ; but the 

 form of the apothecia separates it en- 

 tirely from all the preceding genera 

 of the Colkmei. There seems no 

 reason to doubt that the apothecia 

 really belong to the thallus and not 

 to a parasitic /»//^(<s. 



Pyrenidium actinellitra 'S\\. — a. Thai- 

 line filaments, x30. b. Transverse 

 section of a filament, x200. c. A 

 frustule of the cortex. X 350. d. Go- 

 nimia. e,e'. Vertical sections of two 

 apothecia (viewed under water), x 30, 

 with a small portion of crustose 

 thallus. /. Tlieca with spores, X 350. 

 g. Two spores, X 500. 



1. P. actinellam ^"yl. Flora, 1865, p. 210.— Thallus adnate, 

 thinly crustaeform, thinly steUato-fibrillose at the circumference, 

 the fibrillse equally cylindrical, sparingly branched, but usually 

 effuse, and entirely covered by or almost entirely composed of 

 somewhat erect fibrillse, sordid- or dark-olive (I -f wine-red). Apo- 

 thecia minute, scarcely prominent, almost entirely innate, the 

 pyrenium entirely black ; spores 0.020-24 mm. long* 0,008-9 mm. 

 thick.— Carroll, in Journ. Bot. 1865, p. 286 ; Cromb. Lich. Erit. 

 p. 10 ; Leight. Lich. Fl. p. 36, ed. 3, p. 37. 



The thallus of this species (of which I give Nylander's emended 

 diagnosis) forms small maculae on the substi-atum, which are more 

 or less scattered, or at length confluent. When sterile it is externally 

 very similar to states of Leptoyium microscopicitm ; but under the 

 microscope its tibiillae are seen to be equally cylindi-ical, wliile iu 



