BRYUM. 337 



while in no way agreeing with B. argenteum, to which Braithwaite refers it ; the cells 

 being exactly rhomboid-hexagonal with very thin walls, while B. argenteum has the 

 cells more or less distinctly incrassate, and usually more or less vermicular and some- 

 what obtuse at the ends ; nor is there anything in the habit or leaf form to recall that 

 species. Possibly more than one plant was included in his gatherings, and in any 

 case the specimens appear to represent one of those undeveloped, somewhat abnormal 

 barren forms not uncommon in this genus, and often impossible of identification. 



26. Bryum murale Wils. (Tab. XLV. G.). 



Resembling B. erythrocarpum, but in more dense, compact 

 cushions ; the leaves crowded in terminal tufts, more rigid, wider 

 at the base, oblong, acuminate, margin narrowly reflexed, nerve 

 thick, excurrent in a cuspidate point ; cells distinctly narrower 

 than in the two preceding species, narrowly linear-rhomboid, 

 rectangular at base. Seta %-i inch long, arcuate or hooked 

 above, capsule sub-pendulous or inclined, finally often horizontal, 

 larger than in B. erythrocarpoum, if lines long, wider, oblong- 

 pyriform or widely pyriform, neck shorter and less tapering ; 

 bright red, sometimes contracted at the mouth, persistent ; lid 

 large, obtuse or apiculate, shining. Dioicous. 



Hab. On mortar of walls ; not common. Fr. early summer. 



In the form of fruit this species is somewhat intermediate between B. erythro- 

 carpum and B. atropurpureum, being less tapering in the neck than the former and 

 more so than in the latter ; but it is larger than either, with a more elevated lid ; the 

 narrow cells form a good and easily observed character by which even barren plants 

 may be known. The old black capsules of the previous year may usually be found on 

 the same tuft with the ripening ones. B. murale appears to prefer the mortar of new 

 walls, and sometimes disappears suddenly from spots where it has been very abundant. 

 Like B. caspiticium it sometimes has the capsules small-mouthed and ventricose or 

 widely pyriform. I have found it in very fine fruit but with this condition of capsule 

 very marked ; and in Wilson's Herbarium there is a drawing of the same form, 

 labelled "forma microstoma, " from Bangor ; it has then a very different appearance 

 from the typical form, but as the fruit ripens the distinctiveness diminishes. It is 

 possible that it is in some degree a pathological condition. 



These three species, B. erythrocarpum, B. atropurpureum and B. murale form 

 a distinct and natural group, characterised by their blood-red capsules and small 

 leaves of a fairly uniform type, acuminate with the nerve shortly excurrent and with 

 small, rather narrow cells. B. murale forms a somewhat intermediate link with the 

 next group in areolation and leaf-outline, but differs widely in the acuminate, acute 

 leaves and cuspidate nerve point. 



27. Bryum alpinum Huds. (Tab. XLV. I.). 



In dense, wide tufts, rigid, robust, 1-3 inches high, usually of 

 a deep glossy crimson, or variegated with red and green, with few 

 branches. Leaves usually sub-equal, erecto-patent, when dry 

 straight and closely imbricated, and very glossy, narrowly 

 oblong-lanceolate, obtuse or acute, not or rarely acuminate, 

 decurrent, concave, margin reflexed, entire or faintly denticulate at 

 W 



