T r ibe III. POTTIEÆ.
Plants generally perennial ; innovations fastigiate ; areolation
parenchymatous, quadrate-hexagonal in the upper part, more or
less papillose, very chlorophyllose, dilated and hyaline toward
the base. Calyptra cucullate, rarely mitriform-lobate, smooth.
Capsule generally erect, symmetrical. Peristome simple, rarely
absent, of 16 teeth, either rudimentary, flat and membranaceous,
or more generally perfect, often split to the base into 32 round
filiform indistinctly articulate segments.
3 8 . PHAROMITRIUM, Schimp.
Capsule immersed, globose, without peristome, enlarged at
the orifice after the falling of the lid, soft, loosely areolate.
Calyptra oblique, plurilobate.
1. P. su b sessile, Schimp. Plants short, cespitose : leaves
obovate-oblong, acuminate, with a round costa passing up into a
long pellucid hair-point, bearing in the middle two to four
follicles filled with a granulose mucilaginous mass, often divided
into two to four lamellæ : flowers monoecious ; anthers para-
physate in the axils of a single perigonial leaf near the base of
the perichætium : capsule on a short erect pedicel ; lid large,
plano-convex at base, abruptly narrowed into a short slender
and erect or inclined beak; annulus none. — Syn. Muse. 121.
ScMstidium subsessile, Brid. Pottia subsessilis, Bruch &
Schimp., Bryol. Eur. t. 117.
H a b . On sandy or clayey ground, stone walls, etc. ; plains and mountains;
not rare.
Variable in size, from one or two m.m. to four c.m. or more in length;
borders of- the leaves generally entire near the apex, sometimes with a
few distinct teeth. Pharomitrium exiguum, Austin (Bull. Torr. Club,
vi. 42), mere buds or young plants with scarcely any stems, and with the
borders of the leaves denticulate at the apex, is a variety which is found
also among European specimens.
3 9 . POTTIA, Ehrh. (PI. 2.)
Sparingly branching from the base or simple. Leaves ovate-
oblong, acuminate, soft, opaque, smooth or papillose ; costa
round, rarely lamellose toward the apex. Capsule erect.
Peristome either none or very imperfect, or composed of 16 flat
teeth.
* Capsule without peristome or nearly so.
1. P. cavifolia, Ehrh. Leaves ovate-oblong, very concave,
long-aristate by the excurrent lamellate costa : capsule exserted,
ovate-oblong. — Beitr. 1. 187; Bryol. Eur. t. 118. Gymnostomum
ovatum, Hedw. Muse. Frond. 1. 15, t. 6. Pottia pusilla,
Lindb. Trichost. 218.
Hab. On naked ground ; Platte River, at base of the Eocky Mountains
(B. Ilall); Fort Colville {Lyall); near Carson City, Nevada
( Watsoii).
The leaves are sometimes scarcely aristate and the plants in loose tnfts,
sometimes with a very long white hair and the plants very densely
cespitose.
2. P. m in iltu la , Fuern. Plants minute, annual : leaves
open, ovate and oblong-lanceolate, cuspidate by the excurrent
brown costa, recurved on the borders, minutely papillose on the
back, reddish when old : anthers naked in the axils of perichætial
or in buds composed of two small perigonial leaves : capsule
minute, ovate, truncate ; lid broad, short, conical-obtuse. —
Regensb. Flora, xii, Erg.-bl. 10 ; Bryol. Eur. 1.119. Gymnostomum
minutulum, Schwaegr. Suppl. 1. 25, t. 9. P. Starkei, var.
gymnostoma, Lindb. Trichost. 219.
Hab. Los Angeies, Caiifomia {Bigelow) ; very rare in America, common
in Europe.
3. P. tru n c a ta , Fuern. 1. o. Plants small and simple, or
longer and ramose, gregarious or subcespitose: leaves open,
oblong or obovate, acuminate and mucronate by the excurrent
costa, soft, loosely areolate, concave, flat on the borders, nearly
smooth: capsule broadly ovate, truncate or subcylindrical,
gymnostome ; lid plano-convex, obliquely rostellate, attached to
the columella and falling with it. — Bryol. Eur. t. 120, 121.
Bryum truncatulum, Linn. Spec. PL 1119. Gymnostomum
truncatum, Hedw. Muse. Frond. 1. 13, t. 5. P. eustoma, Ehrh.
Beitr. 1. 187.
Hab. Open ground; New England to Pennsylvania.
4. P. W ilso n i, Bruch & Schimp. Plants simple, loosely
cespitose : leaves close, gradually larger upwards, open, erect,
oval-oblong or ovate-spathulate, rounded at the apex and ouspi