736 



L I C H E 





these are natives of rocks anil trees in Africa. It is 

 named in honour of M. Dufour, the most distinguished 

 liche'nologist of France, and who intends to publish a 

 Lichenographia Gallica, including the species found on 

 the Italian Alps, and on the Pyrenees. 



C. CEPHALOIDEI. 



Cenomyc*. 32. CBNOMYCE. Apothecia roundish, convex, like the 

 capitula of mosses, without a border fixed at the cir- 

 cumference, beneath free, hollow within, covered ; 

 gemmiparous plate covering the whole surface of 

 the apothecium, reflexed at the edges, within of 

 simple texture. Thallus cartilaginous and somewhat 

 crustaceous, leaf-like and laciniated, rarely uniform, 

 producing fistular cup-like processes (podetia), bear- 

 ing the apothecia on their- tips. 



This is an extensive genus ; and it is difficult accu- 

 rately to discriminate the species, owing to the great 

 variableness both of the thallus or frond, and of the po- 

 detia or tubes. The very common Lichen pyxidatus, 

 and L. cocciferus of Linnaeus may illustrate it ; and 

 these and some others readily attract the eye by the 

 PLATE bright red of the tubercles. Many of the species inha- 

 LXXV. bit sterile moorish grounds ; of these, the well-known 

 Fig. 4. $. re in-deer lichen, (L. rangiferinus, Lin.) is the most im- 

 portant. In different species the frond is divided so as 

 to resemble the branching of the antlers of various 

 kinds of deer. Lightfoot describes an alcicornis, and 

 Acharius has added both a damescornis and a cervicor- 

 nis. Other species of Cenomyce, which occur pretty 

 frequently in this country, are, L. uncialis and cornu- 

 tus of Linnaeus ; L. furcatus of Hudson ; and L. ver- 

 micularis of Dickson. The genus is divided into four 

 sections. 1. Phyllocarpa, with the frond foliaceous, 

 lobed and tiled, and very short and indistinct podetia. 

 2. Cladonia, with the frond foliaceous and laciniated, 

 and the podetia cup-shaped. 3. Hclopoilia, frond laci- 

 niated and imbricated, podetia cylindrical and fistu- 

 lar, terminated by apothecia resembling minute fungi. 

 4. Pycnothelia, with the thallus crustaceous and uni- 

 form. 



33. B^OMYCFS, Apothecia circular, convex, shaped like 

 capitula, without borders, solid, sessile ; clothed with 

 the gemmiparous plate, which is reflexed at the cir- 

 cumference, and of simple texture within. Thallus 

 crustaceous, uniform, with short, soft, solid podetia, 

 supporting the apothecia. 



There are only three or four species of this genus. 

 The generic name alludes to the circumstance of the 

 tubercles resembling small fungi, or lycoperdor.s; being 

 derived from /3, small, and fuix.iK, a mushroom. Li- 

 chen ericetorum and L. fungiformis of Withering may 

 be noticed as examples : the former is Baeomyces ro- 

 seus, and the latter B. rupestris of Acharius. 



34. ISIDIUM. Apothecia circular, in a great measure 

 formed of the gemmiparous plate ; at first almost in- 

 cluded within the apex of the podetium, and border- 

 ed by it : afterwards becoming prominent, thick, he- 

 mispherical ; beneath, flat, and sessile ; within, of 

 simple jfexture. Thallus crustaceous or tartar-like, 

 uniform, furnished with solid short podetia, (papillae 

 of some authors), some ban-en, others bearing a gem- 

 miparous plate, or constituting apothecia. 



The name of this genus has been bestowed, on ac- 

 i^ount of its general resemblance to the coral called Isis 

 >ty Linnaeus ; and Lichen coraliinus may be mentioned 



as an example. Only eight species are described by Lichen. 

 Acharius; and one of these, L.^oculatus (Isidium ocel- V T" 1 ~'' 

 latum, Ach.) he received from Trar countryman Dick- A ' harlan 

 son, nor does it appear to have been found elsWhere gen 

 than on the rocks of Scotland. 



35. STEREOCAULON. Apothecia solid, sessile, with a bor- Stereocau- 

 der ; at first turban-shaped, but afterwards acquiring lon - 

 a hemispherical or almost globular form, covered 

 above ; tne gemmiparous plate ultimately dilated, and 

 extending over the border, reflexed; within, of simple 

 texture, somewhat striated. Thalhts shrubwise branch- 

 ed, cylindrical or roundish; within, rather of a woody 

 texture, solid j with a crustaceousbark, set with small 

 granulations. 



Isidium. 



The solid stem (rnptu ***<;) gives name to this ge- 

 nus. It may be exemplified in Lichen paschalis of Lin- 

 naeus, which grows on the rocks of the Highland dis- 

 tricts of this country. 



36. SPH^EROPHORON. Apolhccia somewhat globular, 

 terminal on the branches of the thallus, of which they plioron. 

 are formed ; at length bursting on one side, when 



they are seen to include a mass or ball (of a dark co- 

 lour), which soon falls into powder. Thallus shrub- 

 like, branched, cottony within, rather solid, covered 

 with a cartilaginous bark. 



This is a very well marked genus, distinguished by- 

 its spherical parts of fructification (rfxt* <pot). Only 

 three species are described by Acharius. Lichen fragilis, 

 Lin. (Spaerophoron compressum, Ach.) which is not 

 uncommon on our upland heaths, and which much re- 

 sembles a small coralline, and L. globiferus, Lin. are two 

 of these. 



37. RHIZOMORPHA. Apothecia rather globular, termi- Rhizo- 

 nal, or on the points of the branehlets, filled with a morpba. 

 somewhat gelatinous mass; of simple texture. Thallus 

 branched, filiform, prostrate or creeping, cottony 

 within, clothed with a cartilaginous bark. 



This root-shaped genus includes several plants which 

 have commonly been referred to the genus Clavaria by 

 English writers, and which particularly have been con- 

 sidered as varieties of Clavaria hypoxylon. 



CLASS III. HOMOTHALAMI. 



38. ALBCTORIA. Apothecia circular, thickish, sessile, Alccton.-.. 

 with a border ; afterwards becoming convex, and the 

 border nearly disappearing ; wholly formed of the 

 thallus. Thallus branched, with filiform branehlets 

 (lorula), pendulous or prostrate; v ithin, fu .lous and 



of cottony substance, with a cartilaginous bark. 



The well-known Lichen jubatus of Linnaeus,, or 

 horse-tail lichen, affords an example of Alectoria, a 

 name which is taken from the Greek word for hair. 



39. RAMALINA. Apothecia circular, thickish, somewhat Ramalioa. 

 peltate or sirpported on central pedicles, flat, with a 

 border ; wholly formed of the thallus. Thallus 

 branched and laciniated, in tufts ; within, rather so- 

 lid, but composed of cottony substance, with a carti- 

 laginous bark. 



This genus includes the well-known and common 

 Lichen fraxineus, fastigiatus, and farinaceus of Linnaeus, 

 which are abundant not only on the oak, the ash, and 

 other forest trees, but often infest orchards. Lichen ca- 



