THE BRYOPHYTA OF ICELAND 419 



quent. It occurs both in hogs and along the banks of streams, and 

 also on inundated gravelly ground, usually intermixed in tufts of mosses 

 such as Cinclidiam, Mnium cinclidioides, Sphagnum and Hypmim spp. ; 

 also on wet gravelly soil associated with Lophozia qiiiiujuedcnlata, Ce- 

 phalozia bicuspidata and other Hepaticse. Only sterile specimens have 

 been found. 



FAM. TRIGONANTHK.K. 



58. Cephalozia bicuspidata (L.) Bum. 



Very common on earth, damp gravelly soil, humus-covered rocks, 

 and in bogs up to a height of about 600 metres above sea-level, espe- 

 cially in NW., N. and in parts also of E. Iceland, while it appears to 

 be more rare in S. Iceland. It grows partly in large cushions, for 

 instance on damp ground by streams, partly intermixed in tufts of 

 mosses especially Sphagnum and Dicramim spp. and thrives best on a 

 somewhat damp substratum. Found as a rule in fruit. It varies con- 

 siderably as regards size and colour. 



Var. Lammersiana (Hub.) Breidler grows on very wet ground , for 

 instance along banks of streams, where it forms large green mats in 

 association with other Hepaticse. It is especially common in N\V. Ice- 

 land. The bog-forms, which grow erect among Sphagnum, are slender 

 with spreading leaves. On damp slopes a dark-brown-to-black form 

 frequently occurs, often forming very extensive carpets; it corresponds 

 most closely with var. Loeskeana (Schiffner) K. M., in previous lists it 

 was referred to var. Lammersiana. At the head of deep lava-caves 

 and at the bottom of lava clefts it occurs in association with Alicularia 

 scalaris as much elongated shade-forms. 



Note. Cephalozia Francisci is recorded by Morch from Hafnar- 

 fjordur, but the specimen in the Botanical Museum is C. bicuspidata. 



59. Cephalozia ambigua C. Mass. 



NW. Iceland: Laugarland, fr. !. 



It grew there in small brownish tufts on the damp ground at the 

 bottom of the vallev. 



v 







60. Cephalozia pleniceps (Aust.) Lindb. 



Common in all parts of Iceland except in the southern part, where 

 it appears to be rare. It is especially common in NW. Iceland and 

 forms there one of the most frequently occurring Hepaticse. 



It occurs especially on damp ground and in bogs, woven into tufts 

 of Sphagnum, Dicramim and Mnium hornum or associated with Lophozia 

 Kunzeana, L. quinqiiedenlata and other Hepaticas and as a rule bears 

 calyces or fruit. It occurs most frequently up to a height of about 

 300 metres, but it is also often met with at far greater altitudes. 



Var. macrantha (Kaalaas et Nichols.) K. M. is widely distributed on 

 wet ground, and grows in association with similarly elongated forms of 



