THE BRYOPHYTA OF ICELAND 417 



and caves in the lava-fields, usually mixed witli Blepharostoma tricho- 

 phyllum, Amblystegium Sprucei, Diplophijllum alhicans and PUujiothecium 

 denticiilaliim. The characteristic gemmif'erous shoots occur always, but 

 piants in fruit have not been collected. 



51. Gymnocolea inflata (Huds.) Dum. 



"In Islandia" leg. Morch! and figured in Flora Danica, tab. 1945, 

 fig. 2; SW. Iceland: Krisuvik (Stp.)!; Laiigarvatn (Stp.!); Reykholt (Grl.;!); 

 Rej'kirdalur!; Kolvidarhol!. NW. Iceland : Laugarland!. 



Gronlund records this species from several other localities be- 

 sides those mentioned above, but the specimens in the Botanical Museum 

 in Copenhagen are all wrongly determined and must be referred to 

 Lophozia Miilleri or to L. alpestris. 



In Iceland Gymnocolea inflata is a decidedly warm-soil plant which, 

 with the exception of a single locality, was found exclusively on the 

 steaming clayey flåts around hot springs in SW. Iceland. Near Laugar- 

 land it was growing rather sparingly in a bog. Haplozia crenulata was 

 growing in its neighbourhood, and as there was a small spring with 

 lukewarm water at the edge of the bog it is possible that the occur- 

 rence of the two species is connected with the spring, although there 

 was no characteristic vegetation around the spring, but only the com- 

 nion bog-plants. 



In Reykirdalur, where it is found in abundance near almost all 

 the hot springs, it forms extensive brownish-black or almost entirely 

 black mats on warm ground with a temperature of as much as 40° 

 around fumaroles or on slopes stretching down towards the boiling hot 

 basins. At some distance from the spring it will grow woven into the 

 tufts of Polytrichum commune or mixed with Cephalozia bicuspidata which 

 likewise occurs in brownish-black forms. 



It was collected with calyces only at Laugarvatnshver. 



52. Plagiochila asplenioides (L.) Dum. 



Very common everywhere. 



Plagiochila asplenioides occurs on almost every substratum, on damp 

 or on dry rocks, in bogs, on earth, etc. It is most frequent up to a 

 height of about 300 metres above sea-Ievel, but often occurs as far up- 

 wards as about 600—700 metres. Usually it grows intermixed in the 

 tufts of other Bryophyta, more rarely it forms tufts bj- ilself. The 

 majority of the specimens which have been collected are small, only 

 1—2 mm. broad, with leaves slightly dentate or entire. Larger forms 

 with leaves typicallj' dentate occur mostly on somewhat damp ground, 

 for instance among stones on a talus of loose blocks and debris (Urd) 

 or in caves. Only sterile specimens have been found. 



53. Leptoscyphus anomalus (Hook.) Lindb. 

 E. Iceland: Stod (H.J.)!. 



