SPHJERIACEI. 



[ 703 ] 



SPH/ERIACEI. 



of the polymorphous characters of the asco- 

 phorous forms, but from the circumstance 

 tint it has recently been shown, as was sus- 

 pected before, that there is a relationship 

 existing between them and the supposed 

 genera of Coniomycetous Fungi of similar 

 habit. These last are in fact mostly forms 

 of Sphaeriaceous Fungi, as is indicated 

 under the heads CONIOMYCETES, ASCOMY- 



CETES, DOTHIDEA, SPH^RIA, CYTISPORA, 



SEPTORIA. Our treatment of this family 

 is very imperfect, the knowledge of them 

 being confined to few persons, and much of 

 it lying scattered in fragments. British 

 genera : 



* Stroma erect. 



Clauiceps. Stroma simple, clavate ; peri- 

 thrciii superficial, in a distinct layer at the 

 summit of the clavate stroma ; asci tubular ; 

 spores very long, multiseptate. 



Xyhiria. Stroma simple or branched ; 

 perithecia spread all over, often wanting at 

 the summit, black ; asci eight-spored ; spores 

 uniseptate. 



Fig. 650. 



Fig. 651. 



Fig. 652. 



Xylaria guianensis. 

 Fig. 650. A stroma. Nat. size. 

 Fig. 651. Vertical section of the same. Nat. size. 

 Fig. 652. Section of a perithecium. Magnified 10 dia- 

 meters. 



Thamnomyces. Stroma branched, shrubby, 

 or stalk-like ; perithecia formed from the 

 stroma, more or less naked ; asci tubular ; 

 spores simple, ovate. 



** Stroma between erect and horizontal. 

 Poronia. Stroma cup-shaped, stipitate 



or sessile, margined ; perithecia in the disk, 

 superficial; ostioleaeven slightly prominent. 



*** Stroma horizontal. 



Hypocrea. Stroma distinct from the 

 matrix, tubercular; perithecia immersed; 

 asci filiform ; spores simple or uniseptate. 



Hypoxylon. Stroma distinct from the 

 matrix, at first covered with a floccose 

 mealy veil; perithecia black; asci linear- 

 clavate; spores subseptate, expelled in a 

 cloud of black powder. 



Fig. 653. Fig. 654. 



Xylaria grammica. 

 Fig. 653. Natural size 

 Fig. 654. Horizontal section. Magnified 5 diameters. 



Diatrype. Strorna partly formed from 

 the matrix, not distinct ; perithecia deep- 

 seated, produced into a long neck, and 

 frequently a beak; spores simple and pel- 

 lucid. 



Dothidea. Perithecia undistinguishable 

 from the stroma ; asci collected into a glo- 

 bose nucleus with a neck above, leading to 

 an ostiolate papilla. 



Stroma wanting ; the perthecia often 

 seated on a tuberculous, crustaceous, bys- 

 soid, macular mycelium. 

 Nectria. Perithecia free, membranous, 

 flaccid, brightly coloured, with a pale 

 Dapilla, nucleus pale; asci eight-spored; 

 pores pellucid. 



