TRICHOSTOMUM. 217 



more typical forms of T. mutabik, though more strongly in the variety. Nor is the 

 broad and obtuse apex by any means always correlated with shortness of leaf, usually 

 given as a character of T. littorale ; indeed one of the most frequent of the wide, 

 obtuse-leaved forms is a very large-leaved plant usually found growing under hedges 

 and on shady banks in the south. 



In order to determine the degree of obtuseness of the leaves it is necessary to 

 flatten them out under a cover glass, as when viewed laterally or when slightly 

 infolded at the edges an erroneous impression may easily be produced. It should be 

 remembered, too, that in this and the allied species the leaf edges begin to roll 

 inwards very quickly when the plant begins to dry, and it is necessary that the leaves 

 should be thoroughly expanded before coming to a conclusion on this point. I have, 

 moreover, often examined plants in which the margin at apex was in some leaves 

 incurved while that of others on the same stem was quite plane. 



The mucronate apex of the nerve may be very slightly curved upwards, but never 

 abruptly and markedly as in T. crispulum. It is usually a. more robust plant, and 

 attains as much as three inches in height. 



After careful examination of original specimens of Mollia lutescens Lindb. 

 (Braithw. Br. M. Fl., Vol. I., p, 246), gathered by Lindberg at Glena, Killarney, in 

 1873, I am obliged to confess I can find nothing in it beyond a rather marked form of 

 Trick, mutabile. The leaves are indeed very long, but the variation in this respect is 

 no greater than may well be considered within the limits of so variable a species ; they 

 also appear to be rather more fragile than usual, but this may partly be accounted for 

 by age. In no other respect can I find the slightest difference from ordinary Trick, 

 mutabile. The outline of the cells is not more distinct than is frequently the case in 

 this species, nor are the cells themselves at all more pellucid, but exactly as I have 

 frequently seen them in typical plants. Indeed, the areolation in Trich. mutabile is 

 not really obscure, especially in mature leaves ; the minuteness of the cells renders 

 them somewhat difficult to distinguish unless highly magnified, but under a high 

 power they appear quite distinct. I should be inclined to rank the plant in question 

 under var. cophocarpum. 



3. Trichostomum flavovirens Bruch (Mollia flavovirens 

 Lindb., Braithw. Br. M. Fl.) (Tab. XXXI. I.). 



Much resembling- T. mutabile in habit, but softer, usually of 

 a glaucous or yellowish green, the white base of the leaves very 

 shining and distinct when dry, as is also the back of the nerve ; 

 leaves longer upwards (i-if lines), and crowded in a terminal 

 coma, fragile, oblong-lanceolate or lanceolate from an erect, sheath- 

 ing, hyaline base, quickly narrowed to an obtuse or shortly acute 

 point ; concave, margin inflexed, especially at apex, entire or 

 faintly toothed at middle, verruculose above with projecting 

 papillae ; nerve strong, excurrent in a very short or slightly 

 longer point ; basal cells hyaline, thin-walled, extending higher 

 up the leaf at margin than at nerve, passing abruptly into the 

 chlorophyllose smaller ones, which thus terminate below 

 obliquely, in a V -shaped line; the upper larger than in any of 

 the previous species, and less obscure, sub-quadrate or rounded 

 hexagonal, slightly papillose. Seta dark red below, yellowish 

 above ; capsule oblong-elliptic ; peristome teeth long, filiform, 

 papillose, dark red, erect or slightly twisted. 



Hab. Sandy ground and banks near the sea; South of England and Ireland, 

 frequent, but always sterile. Fr. spring. 



