34° bryace^:. 



the older leaves, is rather brown than red, and the nerve either vanishes below the 

 apex or is barely excurrent. In B. Mildeanum, on the other hand, the upper leaves 

 never show any trace of red, and are usually of a brilliant green rarely if ever found in 

 the other species ; while the lower leaves and the lower part of the stem are often 

 bright red, though not constantly so ; the lower leaves also are almost always 

 distinctly wider than the upper, with more acuminate points and laxer areolation, the 

 latter being constantly wider, or at least as wide as in the most laxly areolated leaves, 

 of the allied plant ; and the nerve is always excurrent, usually in a distinct, rigid 

 mucro, which is longest in the lower leaves. It will be seen from this that the lower 

 leaves form the safest guide to the identity of the species, except as regards colour. 



Considerable variation occurs in the slenderness of the stems, but in other respects 

 it is fairly constant in character ; our British plant appears to be usually more robust 

 than the continental one ; I have gathered it in several localities both in England 

 and Wales, always taller and stronger than is usual on the continent, judging from 

 specimens and descriptions. With the exception of the green form of Bryum 

 alpinum I have found no difficulty in recognising it at once in the field from any of 

 our other species, by the brilliant green tufts with concave, shortly pointed leaves. 

 The margin is often described and figured as strongly revolute, but I have usually 

 found it only slightly, though widely reflexed, so that viewed under the microscope it 

 has somewhat the appearance of the flat edge of a hollow dish. 



B. gemmiparum differs in the more densely imbricated leaves, which are rather 

 more obtuse, with the nerve scarcely excurrent, and the margin less widely and less 

 strongly reflexed. B. caspiticium resembles it, but is known by the more tapering 

 leaves with long hair-points. 



31. Bryum argenteum L. (Tab. XLVI. A.). 



In close tufts or patches, £-1 inch high, pale green or whitish, 

 silvery and shining when dry, slender, with terete julaceous 

 branches. Leaves closely imbricated, hardly altered when dry, 

 small, widely ovate or obovate, variously apiculate or acuminate, 

 very concave, margin plane, entire ; nerve thin, vanishing con- 

 siderably below the summit; cells small, narrowly hexagonal; 

 usually somewhat vermicular, obtuse at the ends, and incrassate ; 

 wider at base ; all very pellucid, the lower very slightly chloro- 

 phyllose, the upper, often for half the leaf quite colourless and 

 hyaline. Seta short, about ^-inch high, arcuate at the top ; 

 capsule pendulous, rarely more horizontal by the stronger curving 

 of the seta, very small, hardly I line in length, shortly oblong, 

 with a very short hardly tapering neck, slightly contracted below 

 the wide mouth when dry, reddish brown, lid wide, conical, 

 orange ; peristome deep orange below, paler above. Dioicous. 



Var. p. majus B. & S. In taller, swollen, greener tufts ; 

 branches stouter ; leaves chlorophyllose almost to apex. Capsule 

 hardly raised above the branches. 



Var. y. lanatum B. & S. (Mnium lanatum P. Beauv.). 

 Shorter, with shorter branches, hoary with the long, flexuose, 

 hyaline, acuminate points of the leaves, very white when dry. 



Hab. Waste ground, cinders, roofs, etc. Abundant. The varieties $ and y 

 more rare ; var. majus in moister shady situations ; var. lanatum in dry warm spots. 

 Fr. late autumn. 



