HYPOTHECIUM. 



[ 338 ] 



ILLOSPORIUM. 



carum, which we found upon a house-fly 

 {Musca domestica). 



BiBL. Duges, Ann. d. Sc. nat. 2 ser. i. 

 p. 20, ii. p. 37; Gervais, Walckenaer's 

 Arachn. iii. p. 265 ; Dujardin, Ann. d. Sc. 

 nat. 3 ser. xii. pp. 243 & 259. 



HYPOTHECIUM.— The term applied to 

 the layer of cellular tissue, on which are 

 attached the thecse or spore-sacs of the fruits 

 of the Lichens. 



H YPOXYLON,Fries.— A genus of Sphse- 

 riacei (Ascomycetous Fungi), distinguished 

 by a sessile stroma, separate and distinct 

 from the matrix (see Sph^eria). The Hy- 

 230xyla of Bulliard with an erect stroma be- 

 long to Xylarta. 



HYSTERIUM, Tode.— A genus of Pha- 

 cidiacei (Ascomycetous Fungi), distinguished 

 by the elliptical or elongated perithecia (figs. 

 360 & 361), bursting by a simple longitu- 

 dinal slit. The species are numerous, grow- 

 ing upon (usually dead) bark, stems and 

 leaves of various plants. H. rugosum has 

 been placed by some authors among Lichens 

 (as Opegrapha macularis, epiphega, Eng. 

 Bot.). It is common on smooth living 

 branches of oak and beech. H. pulicare. 



Fig. 360. 



Fig. 361. 



Hysterimii degenerans. 

 Fig. 36o. Natural size. 

 Fig. 361. Peritheciura. Magnified 10 diameters. 



Fig. 362. 



Fig. 363. 



Fig. 362. Hysterium foliicolium /3 Hederse. An ascus 

 containing eight spores, magnified 100 dia- 

 meters ; with loose spores, magnified 200 

 diameters. 



Fig. 363. Hysterium elongatum. Spores. Magnified 

 400 diameters. 



H. Rubi, H. Pini, and H. culmigenum, the grass 

 Hysterium and H. foliicolium growing on 

 leaves of hawthorn, ivy or oak, are common. 

 The species with septate spores (fig. 363) 

 form the genus Hysterographium, Corda. 



BiBL. Berk. Hook. Br. Flora, vol. ii. pt. 2. 

 p. 293; Ann. Nat. Hist. 2 ser. vii. p. 185; 

 Fries, Summa Veget. p. 368 ; Greville, -Sc. 

 Crypt. Fl. pis. 24, 26, 72, 87, 88, 129 & 167. 



I. 



ICHTHYDINA, Ehr.— A family of Rota- 

 toria. 



Char. No carapace; rotatory organ single, 

 continuous, not lobed nor divided at the 

 margin. 



The rotatory organ is in the form of a circle 

 in Ptygura and Glenophora ; in Ichthydium 

 and Chcetonotus it is long, band-like, and 

 placed upon the ventral surface. 



The family is thus divided : 



Eyes absent. 



No hairs present. 



Tail-like foot simple and truncate Ptygura. 



,, forked Ichthydium. 



Having bristly-hairs. 



Tail simple, truncate Dusydytes. 



Tail forked Chcetonotus, 



Eye single, frontal Sacculus. 



Eyes two, frontal Glenophora. 



Duj ardin places Jc/i^%rfmm and Chcetonotus 

 among the Infusoria; and Ptygura among 

 his Melicertina. 



BiBL. Ehrenberg, Infus. p. 386; Dujardin, 

 Infus. 



ICHTHYDIUM, Ehr.— A doubtful genus 

 of Rotatoria, of the family Ichthydina. 



Char. Eyes absent; body without dorsal 

 hairs ; pediform tail forked. 



Locomotion is effected by cilia placed 

 upon the ventral surface. 



Dujardin places this genus among his 

 symmetrical Infusoria. 



I. podura (PI. 24. fig. 23). Body linear- 

 oblong, often slightly constricted near the 

 anterior turgid and sometimes trilobate end; 

 foot short; aquatic; length 1-140". 



BiBL. Ehrenberg, Infus. p. 388. 



ILLICIUM. See Wintered. 



ILLOSPORIUM, Mart.— A genus of Stil- 

 bacei (Hyphomycetous Fungi), mostly rose- 

 red gelatinous bodies growing upon Lichens, 

 described as consisting of irregular spores, at 

 first involved in a globule of mucus, and 

 afterwards glued together in simple, mealy 

 patches (these plants seem very obscure). 

 Four species are described as British : 



1. I. roseum, Fr. (Grev. Sc. Crypt. Fl. 

 pi. 51). 



2. J. carneum, Fr. (Corda, Icon. Fung. iii. 

 fig. 1). 



3. I. coraUinum, Rob. (Desraaz. Exsicc. 

 no. 1551). 



4. /. coccineum, Fr. (Cord. I. c. fig. 3). 

 BiBL. Op. cit. and Berkeley, Brit. Flora, 



ii. pt. 2. p. 328, Ann. Nat. Hist. 2 ser, v. 

 466 ; Fries, Summa Veget. 482, Syst. My col. 

 iii. 259. 



