MOSSES WITH A HAND-LENS 



15 



Family 2. AnDREAEACEAE. The Andrcaea Family. 



HIS family is characterized chiefly by the 

 dehiscence of the capsule, which splits into 

 four valves after the manner of the Hepaticae, 

 the valves remaining attached at the apex. 

 The plants of this family are all mosses of al- 

 pine or subalpine habitat, growing upon granitic or slaty 



rocks. The appearance is always dark, sometimes black, 



and the leaves are very brittle and dense. The pres- 



■ence of chlorophyll in the leaves is not apparent except 



in very young leaves. There is very little difference 



in the capsules of the different species. 



Andreaea petrophila Ehrh. is common on 



exposed rocks in the mountains of our range. 



It is easily distinguished from any species of 



Grimmia or Orthotrichum by its lack 



of costa, and it is much more 



slender than Hedwigia, and without 



hyaline points to the leaves. The other 



points in its structure are best made 



out from the illustration. It is 



abundant on the face of the Old Man 



■of the Mountain in 



Franconia Notch, 



N. H. 



A. RoTHII W. 



■& M. {A. rupestris 



of many authors) 



occurs with the 



preceding and oc- 



•casionally descends 



to lower levels on 



exposed rocks. It 



has been found 



along the Hudson, 



at Yonkers. It is 



easily distinguish- 

 ed from A. petro- 

 phila by the elon- 



gated- lanceolate 



Figure 



Andreaea Rothii. (From Bry. 

 Leaves and leaf sections. 



Eur.) 



