— 73 — 
i m. long, 0.5 m. broad, the median and upper leaves a little larger, 1.5 mm. 
long, o. 5-0.6 mm. broad, not decurrent at base, ovate or ovate-oblong, short 
acuminate, narrowly decurrent from base to apex, denticulate above, costa 
strong, reddish, 60-65/* thick at base, short excurrent in the middle and 
upper leaves, hardly percurrent in the lower; median and upper cells short- 
hexagonal, 30-35/* long, 12/* broad, with incrassate walls, marginal cells 
linear in two or three rows, lower cells larger, laxer, rectangular, 35-50/* 
long, 12-18/* broad. Capsule oblong, 4-4.5 mm., long, 1-2 mm. broad, nod- 
ding or perdulous, neck abruptly contracted when moist ; operculum convex- 
apiculate. Seta elongated, flexuous, reddish, 4-6 cm. long. Annulus broad. 
Teeth of peristome narrow, pale, reddish above with 18-22 lamellae, 0.35-0.4 
mm. long, 50/* broad at base, basal membrane of the inner peristome adher- 
ent Y> the height of the teeth, segments linear, gaping alopg the keel ; cilia 
very short or none. Spores minute, pale, 12/* in diameter. Plate XXI. 
Nevada: Spooner, Douglas Co., in. large mats on moist banks (C. F. 
Baker, 1902). 
This moss can be placed near B. longisetum Bland., but it is easily dis- 
tinguished from it by the numerous sterile branches arising from below the 
perichaetium, the smaller leaves with a shorter acumen, the peristomial 
teeth, which are narrower and paler, and have more numerous lamellae, and 
finally the much smaller spores. 
(To be Continued.) 
WHAT TO NOTE IN THE MACROSCOPIC STUDY OF LICHENS. 
Bruce Fink. 
Introductory Statement. 
Mrs. Carolyn W. Harris has, in previous volumes of the Bryologist, 
given amateur lichenists a series of descriptions of the more conspicuous 
lichen species, which will prove helpful to workers in determinations and in 
fixing the main features of gross morphology. It is the purpose of the 
present paper to state the principal features of gross morphology, including 
not only the foliose and fruticose lichens, but also extending the statement to 
the most inconspicuous crustose species as well. In so doing, we shall con- 
fine attention to such elements of structure as may readily be seen with the 
unaided eye or with an ordinary hand-lens. 
The Thallus. 
In this study, it is but natural to begin with the vegetative tract of the 
lichen— the thallus. The thallus may be an erect structure, rising from the 
substratum; a pendulous one, hanging downward from it; a conspicuous or 
inconspicuous flat one, closely or loosely attached to the substratum; or an 
inconspicuous one, largely or even wholly imbedded in the substratum. 
Erect and pendulous forms are commonly called fruticose thalli, and the flat 
or horizontal ones may be either foliose, or crustose; foliose when somewhat 
leaf-like, and crustose when a closely attached crust resting on or within the 
substratum. 
