456 HYPNACE^. 



impossible to found the distinction on the presence of the single elongated nerve ; for 

 undoubted plants of H. stellatum not unfrequently have a thin nerve reaching half- 

 way up the leaf, while it is not uncommon in equally undoubted H. chrysophyllum to 

 find leaves with hardly any trace of nerve. Beyond this, I have frequently examined 

 plants which, while exactly agreeing in aspect with H. chrysophyllum, as well as in 

 leaf-form and areolation, show in almost all the leaves the faintest traces of nerve, 

 with occasionally a more pronounced one. The angular cells vary very greatly, and 

 while as a rule in the large, wider leaves of H. stellatum they are large and pellucid, 

 and in the small, narrower leaves of H. chrysophyllum small and opaque, every 

 gradation can be observed between these two conditions. 



The var. erectnm is a very marked form, with much the aspect of robust plants of 

 Plagiothecium pulchellum ; I have received exactly the same plant from the Rev. A. 

 C. Waghome, gathered in Newfoundland. 



A green, not yellowish form sometimes occurs, with shortly acuminate leaves and 

 lax areolation. The typical plant may usually be known at sight by its slender, 

 somewhat silky appearance, the golden colour, dense leaves, etc. 



5. Hypnum Sommerfeltii Myr. (H. polymorphism Wils., 

 non Hedw. ; Campylium hispidulum var. Sommerfeltii Lindb.) 



(Tab. LVI. J.). 



Very slender, stems about i inch long, with numerous, sub- 

 pinnate, slender, erect branches, forming small rather dense tufts 

 of a pale, rarely yellowish green. Leaves rather closely set, 

 spreading and squarrose, sometimes secund at the tips of the 

 branches; little altered when dry; small, about \ line long, 

 from a wide, cordate-oval base Iongly and finely acuminate, 

 rounded at base to a rather broad insertion, finely denticulate in 

 the lower half, nerveless or with a very short and faint single 

 or double nerve ; cells linear, somewhat vermicular, obtuse, 6-10 

 times as long as wide ; almost uniform to base, at angles distinct, 

 few, sub-quadrate, rather small, opaque, forming small but rather 

 well defined, yellowish or dark auricles. Seta about f inch long ; 

 capsule oblong-cylindrical, slightly turgid and gibbous, curved; 

 lid conical, obtusely apiculate. Autoicous. 



H ab. About the roots of trees, on stones, etc. , on calcareous soil principally. 

 Not common. Fr. summer. 



This little plant has the habit and appearance of Atnblyslegium serpens, but 

 is easily recognised by the squarrose leaves, of quite different structure. From H. 

 chrysophyllum it differs in the distinctly denticulate leaf-base, autoicous inflorescence, 

 etc. ; from the other species, except H. Halleri which is quite distinct, in the small 

 size and denticulate leaves. 



6. Hypnum Halleri Linn. fil. (Campylium Halleri Lindb.) 



(Tab. LVI. N.). 



Very slender, stems entirely prostrate, divided, 3-4 inches 

 long, with numerous, pinnate, very short branches, erect or 

 spreading, forming very dense flat tufts, not half-an-inch high, 



