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orthotrichum moss, rock bristle-moss

xerophytic limestone moss

Habit Plants (1–)3–12.5 cm, light green to olive green. Plants to 2.5 cm, appearing glaucous.
Stem

leaves stiff, erect-appressed when dry, narrowly lanceolate to ovate-lanceolate, 2–4.5 mm;

margins recurved to narrowly revolute to near apex, entire;

apex sharply to slenderly acute;

basal laminal cells elongate to rectangular, walls thick, ± nodose;

distal cells 6–13 µm, 1-stratose, papillae 1 or 2 per cell, conic and small, or 2-fid and low.

leaves stiff, closely erect-appressed, incurved when dry, oblong-lanceolate or lanceolate, 2–2.7 mm;

margins recurved proximally, reflexed distally, entire;

apex blunt or obtuse;

basal laminal cells short-rectangular to quadrate, grading to subquadrate at margin, walls thin, not nodose;

distal cells 6–11 µm, 1-stratose, papillae 1–3 per cell, conic or 2-fid, large.

Seta

to 1.8 mm.

1–1.5 mm.

Sexual condition

gonioautoicous.

gonioautoicous.

Capsule

immersed, emergent, or slightly exserted, usually 1/3 emergent, globose ovate, ovate-oblong, or short-oblong, 1.3–1.8 mm, slightly or distinctly 8-ribbed 1/2–2/3 length;

stomata superficial;

peristome single, rarely double;

prostome large, conspicuous, or rudimentary;

exostome teeth 16, erect or sometimes spreading-recurved when old, smooth, scattered-papillose, or coarsely papillose-granulate;

endostome segments absent, or rarely 8, rudimentary, of 1 row of cells, smooth or roughened.

1/2 emergent to short-exserted, oblong-ovate to ovate when mature, oblong to short-oblong when old and dry, 1.2–1.9 mm, strongly 8-ribbed entire length, rarely 16-ribbed with 8 short intermediate ribs, constricted below mouth when dry;

stomata immersed;

peristome single;

prostome rudimentary;

exostome teeth usually 16 when mature, irregularly split, often absent when capsule is old, erect or spreading, papillose-striate to coarsely reticulate-papillose;

endostome segments absent.

Calyptra

oblong, smooth, hairy or rarely naked, hairs finely papillose.

oblong, smooth, hairy, hairs papillose.

Spores

13–21 µm.

10–15 µm.

Specialized

asexual reproduction absent.

asexual reproduction absent.

Orthotrichum rupestre

Orthotrichum pellucidum

Habitat Non-calcareous boulders and cliff faces in mesic areas of pine, spruce-fir, or aspen forests, base of trees, subalpine shade Calcareous or siliceous boulders, cliff faces in xeric areas, direct sunlight
Elevation low to high elevations (100-3000 m) (low to high elevations (300-9800 ft)) moderate to high elevations (500- 3000 m) (moderate to high elevations (1600- 9800 ft))
Distribution
from FNA
AK; AZ; CA; CO; ID; MT; NM; NV; OR; SD; UT; WA; WY; AB; BC; NT; NU; ON; YT; South America; e Africa; Pacific Islands (New Zealand); Atlantic Islands (Canary Islands); Greenland; n Africa; e Asia (Japan); Europe; Australia
[WildflowerSearch map]
from FNA
AK; AZ; CA; CO; ID; MT; NM; NV; OR; SD; UT; WY; AB; BC; MB; NT; NU; YT; Greenland; n Europe
Discussion

In typical form, Orthotrichum rupestre is characterized as much-branched plants in loose tufts with lanceolate leaves, apex narrowly and bluntly acute, basal cells elongate, thick-walled, and nodose, yellowish in older leaves, capsule oblong, emergent, 8-ribbed to mid capsule when old and dry, smooth or slightly 8-ribbed when mature, exostome of 16 erect teeth, coarsely papillose, and calyptra with abundant, spinulose, papillose hairs, some of which extend over the beak.

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

Orthotrichum pellucidum is distinguished by its blunt, lanceolate-oblong leaves that always appear glaucous because of the large 2-fid papillae of the distal laminal cells. When the plants are fertile, which is usually the case, the short-exserted, oblong-ovate, 8-ribbed capsules identify O. pellucidum. The capsule has stomata in the proximal to mid capsule, more or less covered by projecting subsidiary cells.

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

Source FNA vol. 28, p. 65. FNA vol. 28, p. 62.
Parent taxa Orthotrichaceae > Orthotrichum Orthotrichaceae > Orthotrichum
Sibling taxa
O. affine, O. alpestre, O. anodon, O. anomalum, O. bartramii, O. bolanderi, O. consimile, O. cupulatum, O. diaphanum, O. elegans, O. euryphyllum, O. exiguum, O. fenestratum, O. flowersii, O. gymnostomum, O. hallii, O. holzingeri, O. keeverae, O. kellmanii, O. laevigatum, O. lescurii, O. lyellii, O. norrisii, O. obtusifolium, O. ohioense, O. pallens, O. parvulum, O. pellucidum, O. praemorsum, O. pulchellum, O. pumilum, O. pusillum, O. pycnophyllum, O. pylaisii, O. rivulare, O. shawii, O. shevockii, O. sordidum, O. speciosum, O. spjutii, O. stellatum, O. stramineum, O. strangulatum, O. striatum, O. tenellum, O. underwoodii
O. affine, O. alpestre, O. anodon, O. anomalum, O. bartramii, O. bolanderi, O. consimile, O. cupulatum, O. diaphanum, O. elegans, O. euryphyllum, O. exiguum, O. fenestratum, O. flowersii, O. gymnostomum, O. hallii, O. holzingeri, O. keeverae, O. kellmanii, O. laevigatum, O. lescurii, O. lyellii, O. norrisii, O. obtusifolium, O. ohioense, O. pallens, O. parvulum, O. praemorsum, O. pulchellum, O. pumilum, O. pusillum, O. pycnophyllum, O. pylaisii, O. rivulare, O. rupestre, O. shawii, O. shevockii, O. sordidum, O. speciosum, O. spjutii, O. stellatum, O. stramineum, O. strangulatum, O. striatum, O. tenellum, O. underwoodii
Synonyms Dorcadion rupestre, O. bullatum, O. californicum, O. douglasii, O. macfaddenae, O. rupestre var. globosum, O. rupestre var. macfaddenae, O. texanum, O. texanum var. globosum O. cupulatum var. jamesianum, O. jamesianum
Name authority Schleicher ex Schwagrichen: Sp. Musc. Frond. Suppl. 1(2): 27, plate 53 [top]. (1816) Lindberg: Öfvers. Kongl. Vetensk.-Akad. Förh. 23: 549. (1867)
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