482 



A. HESSELBO 



rhomboid, e(|uilateral-hexagonal or almost quadrate cells (forms from 

 AkureyriX to more or less longly pointed, with excurrent nerve, and 

 narrower, rhomboid or elongate-hexagonal cells. 



146. Bryum bimum Schreb. 



E. Iceland: Vallanes. 



It has been collected only 

 scantily on damp ground, wilh 

 capsules which were not ripe 

 at the end of June. 



Two sterile Brya, collected 

 by Helgi Jonsson near Stod 

 in E. Iceland and in Budahraun, 

 are re ferred to this species by 

 C.Jensen. The leaves in both 

 the piants taper to a long point, 

 are longlv decurrent. have nar- 

 vow basal cells, and the nerve 

 excurrent; thereforc, the piants 

 probably belong to Bryum affinc, 

 but owing to the absence of 

 fruit the determination is quite 

 uncerlain. 



147. Bryum affine (Bruch) 

 Lindb. 



Bryiim ciispidainm Schimp. 



Conimonlj' distributed. 



One of the most frcquent 

 species of Bryum, and occurs 

 everywhere in the lowlands on damp sandy or peaty ground, and on 

 humus-covered rocks. The fruit ripens in the iirst half of July. It 

 yaries exceedingly in all its parts. It is said to differ from the very 

 nearly allied B. eirnitnm in its sex, the smaller, smooth spores, and the 

 decurrent leaves with the broader cells; but all these features are so 

 variable that in reality it is hardly possible, at least in the Arctic 

 countries, to separate these two species. 



The plant is usually synoicous, but c? flowers are also almost 

 always pj-esent; $ flowers are more rare. The spores vary in size from 

 0.008 to 0.020 mm., and often differ rather considerably in size in the 

 same capsule, or in different capsules from the same tuft; the most 

 frequent size is 0.012—0.017 mm.; they are sometimes smooth, sometimes 

 fincly papillose. The leaves vary in form from about ovate to lanceolate, 

 tapering more or less to a long point, and with the nerve longly excurrent. 

 In form the leaf-cells correspond nearly with the leaf, so that short 

 leaves have broader cells than have those which are long and narrow. 



Fig. 7. Ilrgum (ir(enhiiidii. Peristome (X250; phot.). 



