41 
We have taken particular pains to see as many specimens of 
Macoun’s No. 588 of S. Muelleri,as possible, thinking that perhaps 
there might be a mixture of specimens, and perhaps our S. mar- 
gimata be found among the number. But Prof. Macoun assures 
us that the species is local, and all the specimens of this number 
were collected from the same place and grew on the same rock: 
This is very interesting, for the specimen in our set agrees with 
Scouler’s specimens of S. aguatica, the ones from Prof. Eaton’s set 
are referable to var. nigrescens, and these last of Macoun’s, he 
assures me, are. the very ones from which Kindberg named S. 
Muelleri. 
Key. 
Leaves bordered by slightly larger, thick-walled cells, in a single layer, green, 
yellow or black, peristome present, . ee SP EET Ny nee I. aquatica, 
Leaves bordered by larger, denser cells in a double layer, often prosenchymatous 
almost to apex, peristome absent,..........2.+--+- seeeesees 2. marginata, 
1. SCOULERIA AQUATICA Hook. 
Scouleria aquatica Hook. Bot. Misc. 1: 33, ¢ 28 (1830). 
Grimmia Scouleri Miill. Syn. Musc. Frond. 2: 654 (1851). 
Scouleria aquatica var. virescens Kindb. Bull. Torr. Club, 16: 93 
(1889). 
Scouleria Muetleri Kindb. Macoun’s Cat. part 6: 62 (1892). 
Scouleria aquatica var. catilliformis Mill. Hedwigia, 32: 207 
(1893). 
Plants dark green or black, gregarious, growing in tufts; stems 
rigid, simple or branching, 5-15 cm. long; leaves when old 
abraded, only the veins remaining, upper green, walls less thick- 
ened, more prominently serrate than the lower, which are often 
black, entire, bordered with yellow or black thick-walled cells; 
vein thick, ending below the apex, often arched and serrate on 
back above and filamentous below; apex rounded and flat or cu- 
cullate, serrate or entire; basal cells variable on the same mi 
on the upper leaves pale often entirely rectangular, on a soe 
Often yellow or brown, with streaks of prosenchymatous cells, ae 
inside the Margin, extending upward irregularly, the 2 
rectangular, often undulate. Capsules almost immerse i ai 
short seta, oblate-spheroidal, becoming more depressed after . 
dehiscence of the lid, which remains attached to the oo > 
and exserted, long after maturity; calyptra Oa es = 
Single, red, teeth 16, irregularly divided and broken, often falling 
