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grimmia dry rock moss

Habit Plants in compact hairy cushions, grayish green. Plants in hoary loose cushions, emerald green to black.
Stems

1–2 cm, central strand absent.

0.6–1.2 cm, central strand weak.

Leaves

ovate to oblong-lanceolate, 0.1–1.15 × 0.3–0.5 mm, keeled, not plicate, margins plane, awns 1–2 mm, very long, smooth to slightly denticulate, flattened basally, long-decurrent, costal transverse section prominent, semi-circular;

basal juxtacostal laminal cells rectangular, sometimes nodulose, thin- to thick-walled;

basal marginal laminal cells rectangular with thickened transverse walls, pellucid in 2–4 rows;

medial laminal cells rounded-quadrate, slightly sinuose, thick-walled;

distal laminal cells yellowish green, 1-stratose with 2-stratose ridges, not bulging, marginal cells 2-stratose, not bulging.

linear-lanceolate to narrowly ovate-lanceolate, 1.5–2.1 × 0.5–0.7 mm, keeled, not plicate, margins incurved distally, awn 0.4–0.8 mm, costal transverse section prominent, semicircular;

basal juxtacostal laminal cells short-rectangular to elongate, sinuose, thick-walled;

basal marginal laminal cells quadrate to short-rectangular, straight, thick-walled, hyaline;

medial laminal cells quadrate, sinuose, thick-walled;

distal laminal cells 2-stratose, not bulging, marginal cells 2-stratose, not bulging.

Seta

straight, to 1 mm.

Sexual condition

dioicous, perichaetial leaves enlarged.

dioicous, perichaetial leaves slightly enlarged.

Capsule

absent in northern hemisphere material, emergent to shortly exserted, yellowish brown, oblate, exothecial cells irregularly short-rectangular, thin-walled, stomata absent, annulus of 1 row of quadrate, thick-walled cells, operculum mammillate to rostrate, peristome present, nearly fully-developed, split and perforated only in apex, papillose.]

occasionally present, immersed to emergent, yellow (rarely brown), ovoid with an open mouth, faintly but distinctly ribbed, exothecial cells rectangular, thick-walled, stomata absent, annulus of 1 row of quadrate, thick-walled cells, operculum rostellate, with a short obtuse beak, peristome present, but rudimentary, teeth composed of only a few basal cells, sometimes perforated.

[seta straight, 1.5–2 mm.

Grimmia reflexidens

Grimmia mariniana

Habitat Dry acidic rock Acidic sedimentary and basaltic metavolcanics
Elevation low [to moderate] elevations (50[-300] m) (low [to moderate] elevations (200[-1000] ft)) moderate elevations 900-1200 m (moderate elevations 3000-3900 ft)
Distribution
from FNA
NF; South America (Argentina, Chile); Atlantic Islands (Iceland); Pacific Islands (New Zealand); Australia
from FNA
CA
Discussion

Of conservation concern.

Previous to its discovery in Iceland, as Grimmia grisea (H. C. Greven 1998), G. reflexidens was known from only the Southern Hemisphere. It had previously been collected east of East Bay, Newfoundland, now the only known locality in North America, but was not recognized as G. reflexidens. The latter is similar to G. asperitricha Dixon & Sainsbury of New Zealand, and the two species have been confused by G. O. K. Sainsbury (1945) as well as by R. Ochyra (1993). J. Muñoz (1998b) synonymized G. reflexidens with G. sessitana. However, the former is readily separated from the latter by: (1) enlarged perichaetial leaves, (2) decurrent awns, (3) non-bulging laminal cells, and (4) dioicous sexual condition. Capsules are unknown from Northern Hemisphere material, but G. reflexidens lacks stomata while they are present for G. sessitana. Although G. reflexidens and G. teretinervis both have decurrent awns they are easily separated by a number of characters: G. reflexidens grows in compact cushions, has long awns, and a semicircular costa; G. teretinervis grows in loose clumps, is hyaline-tipped to short-awned, and has a unique costa that is distally almost completely circular in transverse section.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Of conservation concern.

Grimmia mariniana is known only from the coastal mountains of central California. If fertile, the immersed capsules with rudimentary peristome teeth will separate it from both G. montana and G. alpestris, which, while also being dioicous and without stomata, have long-exserted capsules with fully-developed peristome teeth. Grimmia nevadensis is similar but lacks peristome teeth, has uniformly rectangular, thin-walled basal laminal cells, and does not have hyaline margins. The faint ribs on the capsules of G. mariniana may not be evident when the capsules are not turgid. Sterile specimens can be separated from G. alpestris by the lack of bulging cells, and the narrow leaves. Distinguishing sterile specimens of G. mariniana from G. montana is more problematic, as both have narrowly ovate-lanceolate leaves, with similar areolation. However, the basal marginal laminal cells of G. mariniana are hyaline while those of G. montana are not. Grimmia mariniana is easily separated from G. arizonae and G. pilifera, two other members of the subgenus, along with G. nevadensis, that have immersed capsules. Sporophytically, both G. arizonae and G. pilifera have abundant stomata, well-developed peristome teeth, and rectangular, thick-walled, multi-layered annuli. Gametophytically, the incurved leaf margins of G. mariniana contrast sharply with the recurved leaf margins of G. arizonae and G. pilifera. Sayre noted the similarity of G. mariniana to G. anodon. The straight, centrally attached seta and symmetric capsule usually with rudimentary peristome teeth will serve to separate specimens of G. mariniana from G. anodon. Gametophytically, the long, narrow leaves, with incurved margins and 2-stratose distal laminal cells separates G. mariniana from G. anodon.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 27, p. 238. FNA vol. 27, p. 234.
Parent taxa Grimmiaceae > subfam. Grimmioideae > Grimmia > subg. Guembelia Grimmiaceae > subfam. Grimmioideae > Grimmia > subg. Guembelia
Sibling taxa
G. alpestris, G. americana, G. anodon, G. anomala, G. arizonae, G. atrata, G. attenuata, G. brittoniae, G. caespiticia, G. crinitoleucophaea, G. donniana, G. elatior, G. elongata, G. funalis, G. hamulosa, G. hartmanii, G. incurva, G. laevigata, G. leibergii, G. lesherae, G. lisae, G. longirostris, G. mariniana, G. mollis, G. montana, G. moxleyi, G. muehlenbeckii, G. nevadensis, G. olneyi, G. orbicularis, G. ovalis, G. pilifera, G. plagiopodia, G. pulvinata, G. ramondii, G. serrana, G. sessitana, G. shastae, G. teretinervis, G. torquata, G. trichophylla, G. unicolor
G. alpestris, G. americana, G. anodon, G. anomala, G. arizonae, G. atrata, G. attenuata, G. brittoniae, G. caespiticia, G. crinitoleucophaea, G. donniana, G. elatior, G. elongata, G. funalis, G. hamulosa, G. hartmanii, G. incurva, G. laevigata, G. leibergii, G. lesherae, G. lisae, G. longirostris, G. mollis, G. montana, G. moxleyi, G. muehlenbeckii, G. nevadensis, G. olneyi, G. orbicularis, G. ovalis, G. pilifera, G. plagiopodia, G. pulvinata, G. ramondii, G. reflexidens, G. serrana, G. sessitana, G. shastae, G. teretinervis, G. torquata, G. trichophylla, G. unicolor
Synonyms G. grisea
Name authority Müller Hal.: Syn. Musc. Frond. 1: 795. (1849) Sayre: Bryologist 58: 323. (1955)
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