IIYPOLEPIS. 



[ 409 ] 



nYSTERIUM. 



crowing- uuderground, and bj^ tboiv fiesliy 

 mdehiscent recoptacle, wliicli is excavated 

 into sinuous cavities lined with basidio- 

 sjJores. which are sometimes smooth and 

 sometimes tuberculated (figs. 352, 358). 



See Pi. 27. ti<r. 8. 



BiBL. Tulasue, L. R. & C, Fmir/i Hypo- 

 gcri, Paris, 1851 ; Ann. Sc. N. 3 ser. xv. 2G7, 

 and A>in. N. H. 1851, vol. viii. 19; Berk. 

 Outl. 292. 



HYPOLE'PIS, Bernh.— A genus of 

 Pteridece (Polypodiaceous Ferns), remark- 

 able as varjdng in the condition of the 

 iudusium so as to become uudistinguishable 

 from Polypodium. Seven species, tropical. 

 (Hoolv-er, Stin. 129.) 



HYPOMY'CES, TuL— A genus of Py- 

 renomycetes (Ascomycetous Eungi), pro- 

 posed by Tulasne to include the coloured 

 species which are parasitic and spring fi-om 

 a thick floccose mycelium. Their conidia 

 are often extremely curious, and have been 

 referred to Sepeclotiiuvi, Asterophora, Dac- 

 tyliiim, kc. The species were formerly 

 included in Hypocrea. 



BiBL. De Bary, Bot. Zeit. 1859, 385, 393 ; 

 Tul. Carp. iii. 38. 



HYPOPTERYGIA'CE^.— A family of 

 Pleurocarpous Mosses with a peculiar ar- 

 rangement of the leaves, which are placed 

 in two opposite straight rows united on the 

 upper side of the stem, with a third median 

 row of smaller stipuliform leaves on the 



Fig. 354. 



Fig. 355. 



Hypopterygium. 

 Fig. 354. Natural size. 

 Fig. 355. A leafy branch. Magnified 5 diams. 



under side, bearing a resemblance to the in- 

 termediate leaves in Selagindla (figs. 354, 



355). The cells of the leaves are parenchy- 

 matous and equal in all parts. The genera 

 are all exotic, viz. Hypoptcryyium, Cyatho- 

 phorum, and HelicophyUum. 



HY'POPUS, Dug.— A formerly supposed 

 genus of Acarina, and family Acarea. 



Char. Body ellipsoidal, coriaceous ; palpi 

 absent ; labium oblong, prolonged in the 

 form of a rostrum, and furnished with two 

 long anterior rigid setae ; the posterior pairs 

 of legs but little developed. The forms are 

 numerous, and are found as parasites upon 

 both animals and plants, as Arvicola (the 

 field-mouse), Bonibus (the humble-bee), 

 Musca (fly), some Myriapoda, and even 

 upon other Acarina; also upon ferns, &c. 

 Dujardiu supposed that they were young 

 forms of Gamasus ; Claparede that they 

 were the males of certain Acarea ; while 

 Megnin decides that they are the nymphs 

 of Acari (TyroyJyp/ius, Sec). They have 

 no mouth nor digestive organs ; but are 

 furnished with posterior ventral suckers. 



PL 6. fig. 15 represents a Nyjiopus miis- 

 carum, which we found upon a house-fly 

 (J^Tusca clomestica). 



BiBL. Duges, Ann. Sc. Ned. 2 ser. i. 20, 

 ii. 37 ; Gervais, Walckenaer's Arachn. iii, 

 265 ; Dujardin, Ajin. Sc. Nat. 3 ser. xii. 

 243 & 259 ; Claparede, Zeitschr. wiss, Zool. 

 186S, xviii. 445; Mmray, Ec. Ent. 231; 

 Megnin, Paras. 146. 



HYPOTHECIUM.— The term applied 

 to the layer of cellular tissue, on which are 

 attached the thecoe or spore-sacs of the 

 fruits of the Lichens. 



HYPOX'YLON, Fries. — A genus of 

 Sphaeriacei (Ascomycetous Fungi), distin- 

 guished by a sessile stroma, separate and 

 distinct from the matrix (see Sph^^ria). 

 The Hypoxyla of BuUiard with an erect 

 stroma belong to Xylaria. 



HYSTE'RTUM, Tode.— A genus of Pha- 

 cidiacei (Ascomycetous Fungi), distin- 

 guished by the elliptical or elongated peri- 



Fiff. 357. 



Fig. 356. 



Hystejiiim degenerans. 



Fig. 356. Natural size. 



Fig. 357. Perithecium. Magnified 10 diameters. 



thecia (figs. 356, 357), bursting by a sim- 

 ple longitudinal slit. The species are nu- 

 merous, growing upon (usually dead) bark, 



