REVUE BRYOLOGIQUE 17 



Jt* 



Plagiothecium MiiUerianuni Schp. 



and the allh'd species 



In a recent number of Uie Journal of Botany (July, 1898) 

 I published some notes on the above moss, with a plate 

 illustrating some of its leading characters. Since that was 

 written, I have seen more of the plant, and I think a few 

 observations will not be without interest. 



During arecent visit to Scotland I have had further oppor- 

 tunities of studying P. MuUeriaimni in the field, having 

 gathered it in some quantity and in several new localities, 

 all however within ahmited area, viz. that group of hills 

 in west Perthshii-e of which Ben Lawers forms the eastern 

 and Ben Lui the western outpost. The flora of this group 

 of hills is well known to be a remarkably rich one, and its 

 character is without doubt due in great measure to the 

 beds of friable micaceous schist of which the summits and 

 indeed the greater part of the hills consist. It is in crevices 

 of rocks formed of this mica schist that P. Midlcnanvm is 

 found, often creeping among and hidden by other mosses, 

 saxifrages, etc. ; it is more frequently growing on the 

 rotten debris of the friable rock than on its harder surlace 

 or the bare ground. It has usually a brighter gloss than 

 either P. pulchclimn B. S. or P. elegans Sull. (P. Jiorrr- 

 rianum Spr-) ; ^^ith the former (especially as the var. 

 mtlduhim) it is frequently mixed, while the latter too is 

 ollen found in close proximity. P. Midlcriamnn ishowever 

 rarely to be confused with either ; it is a larger, paler 

 plant than P. pulchcllum var. nitiduJum, and its mr.nner 

 of growth is very different from that of either species, it 

 is a straggling plant with long, rather straight, extremely 

 narrow, simple fronds, which frequently attain an inch in 

 length, and even two inches (5 cm.) or more. The leaves 

 mostly point strongly forwards, not spreading widely from 

 the stem, giving a markedly narrow character to the trona , 

 so much so that P. MitUcnammr may as a rule be 

 recognised at a glance by this character alone Alter seein^ 

 the plant a few times in the field it is impossible to confuse 

 it with any other, except in the rare cases when he whole 

 plant is reduced to the slender, attenuated branches which 

 simulate the gr-owth of P. pulchellnm var. intuluhwi. 



P. e%«//6-r although ascending to quite high altitudes 

 may be considered to be properly a lowland oj perhaps 

 rather a subalpine moss, as shown by its general distribu- 

 tion and by the low elevation of its fruiting statons 

 P. MiXllcriamcm on the other hand is a dislincly alpine 

 moss, although its range of altitude is considerable; I have 



