MENISCIE.E. 



[ 423 ] 



MESOCARPUS. 



BiBL. Siebold, Sieb. u.Kblliker's Zeitschr. 

 Bd. 2. p. 356, and the Bibl. therein. 



MENISCIE^.— A sub-tribe of Polypo- 

 dseous Ferns, without an indusiura, contain- 

 ing the a:enus — 



MENISCIUM, Sehreb.— Sori reniform, 

 seated on the backs of the transverse ve- 

 nules. Veins pinnate, anastomosing. 



MENISPORA, Pers.— A genus of Muce- 

 dines (Hyphomycetous Fungi), one species 

 of which, M. Jucida, Corda, is recorded as 

 British, growing on decayed wood. 



Bibl. Berk, and Broome, Ann. Nat. Hist. 

 2 ser. vii. p. 101 ; Corda, Icones, i. pi. 4. 

 fig. 223. 



MENTHA, L.— The genus of Labiate 

 (Dicotyledonous Flowering Plants) to which 

 belong the Peppermint, Pennyroyal, Spear- 

 mint, and other mints. These owe their 

 aromatic properties to Glandular hairs 

 upon the epidermis. 



MERENCHYMA.— A name applied by 

 some authors to the form of vegetable cellu- 

 lar tissue where the cells are of circular, 

 ellipsoidal, or iiTegularly rounded outline; 

 ordinarily kno\^^a as " lax parenchjma." 



MERiDION, Leibl.— A genus of Diato- 

 niaceaj. 



Char. Frustules (in front view) wedge- 

 shaped, united laterally so as to form seg- 

 ments of circles or spiral bands. Aquatic. 



Frustules in side view obovate, and fur- 

 nished with coarse transverse striae visible 

 under ordinary illumination, and which ex- 

 tend into the front view. 



Klitzing distinguishes Meridian, in which 

 the frustules form a spiral (helical) band, 

 from Eumeridion, in which they form a con- 

 volute band. 



Meridian circulare, Ag. (PI. 13. fig. /; 



a, front view; b, side view). Frustules in 

 side view simply obovate, forming a spiral 

 (helical) band or filament; length of frus- 

 tules 1-600 to 1-375". 



Meridian canstrictum, Kg. (PI. 12. fig. 28, 

 filament flattened and frustules (front view) 

 separated by drying ; a, convolute filament ; 



b, side view). Frustules in side view con- 

 stricted near the broad end, attenuate to- 

 wards the narrow end, and attached to a 

 hemispherical stipes or cushion. 



Bibl. Klitzing, Bacill. p. 41, and Sp. 

 Alg. p. 10; Ralfs, Ann. Nat. Hist. 1843. 

 xii. p. 457. 



MERTSMOP^DIA, Meyen. See Sar- 

 ciNA and GoNiUM. 



MERMIS, Duj.— A genus of Entozoa. 



M. nigrescens resembles Gordius, but dif- 



fers from it principally in the vulva of the 

 female being transverse and situated near 

 the anterior end of the body, whilst in Gar- 

 dius this is placed at the posterior end. 

 Eggs black. 



It is found in the newly dug-up damp 

 earth of gardens, and in the intestines of 

 insects. 



Bibl. Dujardin, Ann. des Sc. nat. 2 ser. 

 xviii. p. 129, and Hist. nat. d. Helminthes, 

 p. 294; Siebold, Entomolog , Zeitimg, 1842. 

 p. 146. 



MERULIUS, Hall.— A genus of Agaricini 

 (Hymenomycetous Fungi), distinguished by 

 the veiny or sinuously plicate folds of the 

 hymenium, these folds not being distinct 

 from the flesh of the pileus, and forming 

 angular or serrated pores. M. lacrymans 

 is the dry-rot fungus. The mycelium is 

 composed of filaments creeping in the sub- 

 stance of the infected wood, disorganizing 

 and feeding on this as it decays. The fruit 

 is at first white and cottony, forming an 

 eff*used pileus from 1 to 8" broad, subse- 

 quently ferruginous or deep orange. The 

 irregular folds finally discharge a wateiy 

 liquid, whence the name. 



Bibl. Berk. Brit. Flora, ii. pt. 2. p. 129; 

 Sowerbv, Fungi, pi. 113. 



MESOCARPUS, Hassall {Spharocarpus, 

 Kiitz.). — AgenusofZygnemaceae(Confervoid 

 Algse), with evenly distributed cell-contents, 

 producing in conjugation a cross branch, in 

 which is formed a round spore. It often 

 happens that all the successive members of 

 a long series of cells conjugate with another 

 similar series, so as to produce a ladder-like 

 body, the "rounds" of which are formed of 

 the transverse processes {trabeculce, Kiitz.). 

 The only kind of reproduction yet observed 

 is that by the spores formed in the transverse 

 branch from the conjoined contents of two 

 cells, but it is probable that zoospores and 

 encysted conditions of these occur, as in 

 Spirogyra and Mougeotia. The stellate 

 encysted bodies found in most of the allied 

 plants have been seen in M. scalaris by 

 Thwaites. Thwaites also observed a division 

 of the contents of the spore into four parts, 

 such as occurs sometimes in (Edggonium. 



1. M. scalaris, Hass. (fig. 138. p. 166). 

 Sterile filaments 1-1800 to 1-1440" in dia- 

 meter, 6 times as long; sporanges oval or 

 round. Hass. pi. 42. 



2. M. depressus, Hass. Sterile filaments 

 1-2880 to 1-2400", 6to8 times as long; spores 

 globose or elliptical. Hass. pi. 44. fig. 1. 



M. intricatiis, Hassall, is apparently the 



