200 MKKN'i i.vNf;r.. iM.-N. Kl. 



React. I I\iii( iiiiiiii I c (Ticnilco iik»x ficcoloratum, asci srduni persi- 

 stenter caerulescente.s. I lypotheciuin J caerule.scens. Medulla J caeru- 

 lescciis, intfrrltim flistinctc et persistenter, srr] interrjiim + fugaciter colo- 

 rata et iiiterdiiin Icic incolor.ita. 



In. l'KiKS .States: jodo stratiini corticale caerulescit. (Lieh. Scand. p. 

 106I, Oi.ivikk: Thalle J + bleu (Lieh, de l'Ouest p. 105), Harma.mj: Les 

 hvi)hes, par J, de\ieniient d'un beau bleu \iolacé, qui n'est bien vi.sible 

 que dans la couche uiédullaire (Lieh, l'rance p. 594). 



In some specimens I found a very distinct and persLstent blue colour 

 of the medulla bv J, in others I could hnd no reaction whatever, if J was 

 added to a p'wcc of the thallus; but if it was applied to a thin section of 

 the same thallus, the medulla took a distinct blue colour which soon passed 

 into a reddish-brown. In some thalli the blue colour was so faint that it 

 was hardly perceptible. — The reaction belongs to the medulla itself, not 

 to the cortex, but it is most distinct near the lower cortex. 



Crfraiia glauca is a very variable plant, and many varieties or formae 

 have been described. We can first set aside the 'Lichen ampullacens L', 

 produced by a parasitic fungus [Abrotlinlliis Siuithii). Its vesiculoso-inflate 

 laciniae have frequently been mistaken for apothecia by less experienced 

 collectors. The 'f niiipiillacca is common in Southern Norway. 



The colour of the lower face varies from black through a variegated 

 black and white to almost entirely white (an entirely white colour is, how- 

 ever, very rare in Norway), the latter forma being called var. _/c?//rt.v (Web.). 

 It is natural to arrange the variations after this character, but there is every 

 transitional stage between black and white. 



The margin is rarely entire, usually crenato-incise or minutely incise. 

 At moist stations incise margins frequently develop coralline formations, in 

 extreme cases covering the whole thallus, as if it were clothed with Stereo- 

 caillou naniiiii. Coralline forms are called f. coralloidea Wallr. 



Occasionally the development of the coralline formations is checked, 

 the initial 'corals' dissolving into soredia (f. sorediata). 



But these qualities do not combine with others so as to form well 

 defined varieties. On the contrary coralline specimens are found in the 

 /"(■//A^.v-group as well as in the type, and all the formae are confluent. 



var. fallax (Web.) Ach. 



Akersh. Kraakstad, f coralloidea (Somrft.), Kristiania (Lixds.), Aker: 

 Lutvand, i. ampullacea (B. L.), Bogstadaasen (Somrft.), and Fyllinga (B. L.), 

 Minne (B. L.). 



Telem. Vestfjorddalen, f coralloidea (Kiær). Aiisfagd., Nergaren, f. sore- 

 diata (B. L.).. 



Hord. Tysnes: Vaage (H.), Siggen (H.), Os, f. sorediata (Lillef.), 

 Strandebarm: Hjertneshagen (Lillef.), Isdalen, f. sorediata (H.), Lygrefjor- 



