THE BKYOPHYTA OF ICELAND 607 



Iceland, hut the reason why in the following only the Bryophyte 

 vegetation of South Iceland is mentioned, is because it is only this 

 part of Iceland that has been somewhat thoroughly investigated. 

 Fljotshlid. North of the great river Markarfljot, the country 







rises to a height of 200 GOO metres. The slope stretching down- 

 wards to the Markarfljot is trenched by a great number of smaller 

 streams, many of which flow at the bottom of deep, narrow clefts 

 in the turY-lavers. 



/ 



One of the longest and deepest clefts is Bleiksagil near Bar- 

 karsladr (Fig. 31). This cleft has almost everywhere vertical or 

 overhanging sides, 100 or more metres in height, and is so narrow 

 at the top that in some places goats can jump across it. It is 

 therefore quite inaccessible for the greater part of its length, hence 

 only its lower part has been investigated. The sides were there 

 usually covered with enormous mats of mosses of which the prin- 

 cipal species w r ere Hijpnum falcatiun, H. filicinum, H. inolhisciim , 

 Rrachijthecinm riuulare and Philonotis fontana, all of which were 

 developed to an unusually luxuriant degree. H. falcatum and H. 

 filicinum were in many places thickly covered with ripe capsules. 



In this moss carpet a great number of other Bryophyta were 

 found, partly intermixed with each other, partly in larger or smaller 

 tufts or growths. The following species were observed: Philonotis 

 tomentella, Brynm a j neum, B. pallens, B. ventricosum, B. inclinalum, 

 Miuobryum albicans, Mninni serratum, M. punctatnm, Anomobryum 

 /iliforme, Encalypta ciliata, Didymodon rubellns, Barbnla cylindrica, 

 Distichium montanum, Hymenostyliiim curuirostre, Ancectanaiiim com- 

 pactum, Amphidiiim Mougeottii, A. lapponicum, Haplozia riparia. H. 

 cordifolia, Lophozia quinquedentata, L. Mtilleri, Scapania irrigua, 

 Blephorostoma trichophyllnm, Madotheca Corda>ana, Radula compla- 

 nata, Metzneria fnrcata and Marchantia pohjmorpha. At the base 

 of the rock-side grew, among others, Mninin nndiilatuin and Thni- 

 dinm tamariscinum. At the extreme end of the cleft, where the sun 

 could shine on the rock faces, fruiting specimens of Preissia commu- 

 tata often grew 7 in abundance. The walls in the numerous caves 

 were often covered with Eiirhyiichinin Sivartzii and Fegatella conica, 

 in company with many, or a few, of the species found on the sides 

 Of the cleft, which, however, on the whole, did not thrive well in 

 the scanty light. In many places Feyalella formed also a belt along 

 the basal part of the rock-sides, especially where they projected. 

 On the roof of the caves Blepharostoma trichophyllnm and Ambly- 



