liKRN'T I.Y.NGi:. M.-N. Kl. 



Till liaidly ;iny nllu r lV)liaccou.s great lichen sr» well enrliiring 



the smoke of the town. It is only a few years since it disappeared from 

 the stones in the botanic garden of Kristiania. 



It is generally stated that the chemical reactir)n of the medulla in this 

 species is 'K()ll e fla\(> lubescens'. N^laxdek found specimens with the 

 reaction 'KOI I ilavescens' and referred them to a new species P. lusitana ; 

 he also found specimens with the reaction 'medulla KOI I immutata, and 

 called them l\ sithconsprrsa. 



raniiilia siihcoiispcrsa was not found in the Norwegian material. — 

 About half the specimens of 'P. couspcj'sa sensu latiore i. e. P. sloiophyllo 

 + isidiata gave the typical red KOH reaction, a few a pure yellow colour 

 and a considci^able number an intermediate, orange colour. The reason of this 

 is easily seen if the test is made under the microscope: The 'typical' red 

 colour is due to an abundant precipitation of red, often fasciculate cr3'stals 

 of salicininic acid (according to Zopf Flechtenstofife p. 196, Salizininsäure). 

 In other specimens this precipitation is moi'e or less scarce. Sometimes a 

 careful microscopical investigation is necessary to detect a few crystals, and 

 the macroscopical colour is purel}' yellow, and in a few plants the precipi- 

 tation entirely failed to^ appear, giving an orange, resp. a purely yellow 

 colour. 



Harmand's Lieh. Gall. rar. 113 {P. /iisitaiia Nvl.) gave a purely yellow 

 colour and no precipitation. 



It is evident that the difference between the red, the orange and the 

 yellow colour is only due to a difference of the quantity of some chemical 

 substance, and accordingly insufficient to distinguish between two species. 



It is well knowm that 'P. couspcrsa sensu latiore is a very variable 

 species. The most noticeable variation refers to the developmont of isidia 

 and the form of the laciniae. 



Hoffmann's description in Enum. lieh. (1784) p. 78 and tab. X fig. 3 

 (s. n. Liclirii cciitrifiigns) refers to the isidiate form, at least it includes it; 

 the isidia are described and depicted as 'tubercula arbuscula ramosa vel 

 cylindrica.' In his PI. lieh. I (1790) p. 78 and tab. XM fig. 2 Hoffmann 

 describes and depicts the isidia of 'Squaniaiin cciitiifiiga . (The real Pariii. 

 cciitrifnga (L.) is very rare in Central Europa, and P. couspcrsa has been 

 confused with it). 



Lichen coi/spcrsi/s Ehrh. in lit. was described in Acharius Prodromus 

 (1798) p. 118 as different from Lichen centrifugus. Acharius was the first 

 to make a distinction between the isidiod type and the stciiophylla: Metho- 

 dus (1803) p. 205 under Parmclia couspcrsa: . . . 'Non raro pulvinulis ra- 

 mulosis confluentibus maximam partem obtectus est hujus Lichenis thallus, 

 praecipue versus centrum'. No such 'pulvinulis' are- described for the 

 stcnopliyUa which is furnished with 'laciniis pinnatifidis longis linearibus 

 flexuosis imbricato-complicatis' (1. c. p. 206). />'. sicuophylla has 'punctis 

 tenuissimis nigris in pagina superior!" in common with the type (evidentlv 



