EURHYNCHIUM. 423 



Ren. ; this however I have not seen from Britain. The stem-leaves, too, vary much 

 in the length and character of the acumination, some forms being so abruptly and 

 longly filiform as to resemble those of E. piliferum, while others are only very shortly 

 acute ; the nerve may be very thick and reaching high up in the leaf or almost 

 altogether wanting ; and the leaves, again, may be so closely imbricated as to render 

 the stems terete and almost julaceous. I have gathered a very robust form in Skye 

 with the branching alternate, not at all dendroid, and more resembling a Brachy- 

 thecium in habit. The seta is very persistent, and old capsules may usually be found 

 in company with those of the present year. 



This species most resembles Isothecium myurum, and some forms are difficult to 

 distinguish in the barren state ; but the yellowish colour of the present plant, the 

 more attenuated branches, acuminate leaves more strongly denticulate, and the 

 rectangular, not quadrate angular cells are usually sufficient to distinguish it ; and, 

 when fruiting, the squarrose-pointed perichfetial bracts and inclined, more arcuate 

 capsules. With that exception it is not a difficult plant to recognise, at least with the 

 microscope ; the areolation, and especially the small obscure angular cells, being very 

 different from that of almost all our pleurocapous mosses with single-nerved, acute 

 leaves. 



12. Eurhynchium circinatum B. & S. (Hypnum circinatum 

 Brid.) (Tab. LIV. I.). 



In smooth, dense tufts, bright green, often becoming 

 yellowish when old. Primary stems creeping, stoloniform, 

 secondary ascending, curved, about 1 inch long, with numerous, 

 crowded branches at their summits, which are strongly arcuate- 

 decurved, very short, slender and cylindrical, or julaceous. 

 Leaves of the secondary stems minute Q-i line), widely ovate, 

 shortly and widely, often obtusely acuminate, lightly plicate when 

 dry ; of the branches narrower, oblong-lanceolate, acute, crowded, 

 erecto-patent when moist, closely appressed and imbricated when 

 dry, rendering the branches terete and cylindrical, or with the 

 leaf-points a little falcato-secund ; margin recurved at base, 

 coarsely denticulate at apex, more finely below ; nerve very 

 strong and wide, reaching nearly to apex. Areolation very short , 

 median elliptic-rhomboid , j-4 times as long as broad, the walls 

 firm, somewhat incrassate ; shorter at apex, at base and angles 

 short, irregularly quadrate, rather opaque, covering a large area. 

 Seta short. Capsule ovate-oblong, oblique ; lid with a moderately 

 long beak. Dioicous. 



Hab. Rocks, principally calcareous ; South of England and Ireland, rare. Fr. 

 spring, not found in Britain. 



Resembling in habit small forms of Pterogonium gracile, but more slender with 

 shorter, more curved branches, and very different in the single-nerved leaves. From 

 the next species it differs in the densely crowded, not shining leaves and strongly 

 curled branches. From all the other species of the genus it differs in its short firm 

 areolation ; and indeed it is not likely, from its habit alone, to be confused with any 

 other plant. The fruit is very rare, but is found in some abundance in certain 

 localities in the South of Europe. 



