PERTGONIMUS. 



PERISPORIUM. 



PERIGON'IMUS, Sara. A genus of 

 Atractylidae (Hydroid Zoophytes). 



Differs from Atractylis in the simple fixed 

 spore-sacs being rnedusiform. 



On other marine zoophytes, shells, &c. 



BIBL. St. Wright, Pr. Roy. Soc. Edin. \ 

 1857, 1858; Ann. N. II. 1861, 180; Alder, | 

 Trans. Tynes. F. C. v. 230 ; Allnian, Ann. 

 N. H. 1863,1864; Hincks, Hytl Zooph.SQ. 



PERI'OLA, Fries.-P. tomentosa, Fr., i 

 described as a Sclerotioid Fungus, is an j 

 obscure, irregular, fleshy body, with a white 

 villous surface, found growing on potatoes. 

 It is probably the early form of some unas- 

 certained species of fungus. This was cha- 

 racteristic of those forms of potato-rot 

 which were known before the introduction 

 of the Peronospora. 



PERIP'TEBA, Ehr. A genus of Dia- 

 toinaceae. 



_ Char. Frustules single, compressed; valves 

 dissimilar, one being simply turgid, the 

 other winged or furnished with horns ; 

 horns sometimes branched and attached to 

 the extreme margin. Fossil. 



Valves not areolar nor punctate under 

 ordinary illumination. America and Ber- 

 muda. 



P. chlamidophora (PL 50. fig. 41) ; P. te- 

 tracladia (PI. 18. fig. 66) ; P. copra (PI. 18. 

 fig. 67). 



BIBL. Ehrenb. Ber. Berl. Ak. 1844. 263 ; 

 Kiitz. Sp. Alff. 25. 



PERISPIRA, St. A genus of Holotri- 

 chous Infusoria. Free, ovate; mouth an- 

 terior ; oral cilia extending spirally towards 

 the posterior end. 



P. ovum ; green, = Hoplonhnia ovum ? 

 (Kent, Inf. 611.) 



PERlgPORIA'OEL A family of Asco- 

 mycetous Fungi, mostly epiphytic and of 

 small size, characterized by producing floe- 

 cose common receptacles (mostly) radiating 

 from a point, forming patches upon leaves, 

 &c., in the centre of which are developed 

 somewhat globular perithecia of obscure 

 cellular structure, persistent, bursting at 

 the summit, filled densely with subgelatin- 

 ous, scarcely diffluent gektine ; sporidia 

 produced in asci, subsequently often effused, 

 simple, free, and mixed with the gelatine 

 in the centre of the perithecium. The my- 

 celia of these plants, bearing conidial struc- 

 tures, have been described as distinct fungi, 

 for example those of Erysiphe as Oidia, 

 &c. See ERYSIPHE. EUBOTIUM probably 

 belongs here. British Genera : 



Lasiobotrys. Perithecium fleshy-horny, 



globular, naked, collapsing at the sum- 

 mit. 



Capnodium. Perithecium fleshy, clavate, 

 double (the outer cellular, interior hya- 

 line), mucilaginous, opening by a fringed 

 mouth ; asci containing' about six spores in 

 two rows. 



Erysiphe. Perithecium membranous, 

 closed at first, afterwards open, supported 

 on a persistent radiating mycelium formed 

 of continuous filaments bifid at their ends. 

 Asci one to eight, paraphyses none ; spores 

 definite, ovate. 



Pensporium. Perithecium superficial, 

 at length bursting irregularly. Asci club- 

 shaped, not mixed with paraphyses. Spores 

 numerous, ovate. 



Chcetomium. Perithecium superficial, 

 finally open at the mouth, clothed externally 

 with opaque hairs. Asci clavate, mixed with 

 paraphyses. Spores simple, ovate. 



Ascotricha. Perithecium thin, at length 

 bursting, clothed with dark, subpellucid, 

 even, obscurely-jointed hairs. Spores sim- 

 ple, contained in linear asci. Superficial, 

 at length free or resting on the investing 

 thallus, black. 



Orbtcula, Cooke. Perithecium seated on 

 a distinct mycelium, reticulated. Ostiolum 

 obsolete ; sporidia subglobose ; paraphyses 

 simple or branched. 



PERISPO'RIUM, Fr. A genus of Pe- 

 risporiacei (Ascomycetous Fungi), consisting 

 of minute, globular, free, punctiform sacs, 

 with fleshy or waxy walls, seated on an 

 obscure thallus, growing on leaves or stalks ; 

 finally bursting and collapsing. The spores 

 are produced in large numbers in swollen 

 clavate asci (fig's. 558, 559), which are un- 

 accompanied by paraphyses. 



Fig. 558. 



Fig. 559. 



Perisporium disseminatum. 



Fig. 558. A perithecium in vertical section. Maeni- 

 fled 100 diameters. 

 Fig. 559. An ascus detached. Magnified 300 diams. 



BIBL. Fries, Sum. Veg. 404 ; Syst Myc 

 iii. 248 ; Berk. Ann. N. H. vi. 432. 



