Racomitrium lanuginosum

(Hedwig) Bridel

Muscol. Recent., suppl. 4: 79. 1818,

Basionyms: Trichostomum lanuginosum Hedwig Sp. Musc. Frond., 107. 1801
Treatment appears in FNA Volume 27. Treatment on page 294. Mentioned on page 32.
Click plate for higher resolution version.
Illustrator: Patricia M. Eckel
Plants forming dark or grayish to yellowish green, yellowish to blackish brown tufts or patches, usually hoary when dry. Stems to 15 cm or more, radiculose at the base or not. Leaves crowded, erect-appressed when dry, erectopatent when wet, straight to falcate-secund, linear-lanceolate, 3–5 × 0.6–0.9 mm; margins recurved to revolute for 1/2–2/3 the leaf length, entire proximally the echlorophyllose part formed by decurrencies from the awn; apices gradually tapering to a long and slender awn, not decurrent, canaliculate distally, concave to broadly carinate proximally, awn hyaline, densely papillose, broadly and evenly decurrent to 1/4–1/3 along the margins, with decurrencies consistently flat, erosodentate to nearly entire and short, to 30 µm, sharp or blunt teeth, distinctly papillose throughout, spreading at a 40–90º angle; costa in tranverse-section rectangular to reniform in outline, strongly convex abaxially, 75–100 µm wide basally; basal laminal cells long-rectangular, 40–90 × 7–8 µm, strongly nodulose, forming a broad orange strip along the insertion; medial cells becoming long-rectangular to linear, 50–60 × 6–8 µm wide; distal laminal cells short-rectangular, (10–)15–40 × 7–9 µm. Seta 1–3 per perichaetium, brown to reddish brown, 3–7(–10) mm, erect, flexuose. Capsule brown, 1–1.7 mm, smooth, glistening; peristome teeth (300–)500–700(–900) µm, reddish brown, arising from a low basal membrane, 2-fid almost to the base into filiform, terete, densely spiculate-papillose divisions. Spores 8–12 µm.

Habitat: Dry, exposed areas, mostly with high light intensity, acidic or seldom calciferous soil and rocks, boulders, cliffs, ledges, scree and in fellfields, polar tundra and tundra-like barrens in mountains, hummocks in peatland and moorland, over raw earth of bog margins
Elevation: low to high elevations (0-2300 m)

Distribution

V27 403-distribution-map.gif

Greenland, Alta., B.C., Man., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., Que., Yukon, Alaska, Calif., Idaho, Maine, Mont., N.H., Oreg., Wash., Central America (Costa Rica), South America (Argentina, Chile, Colombia, Ecuador, Peru), Europe, arctic and temperate Asia (including Borneo, Java, New Guinea, Sumatra), South Africa, Atlantic Islands (Azores, Canary Islands, Falkland Islands, Gough Island, Iceland, Madeira, South Georgia, Tristan da Cunha), Indian Ocean Islands (Heard Island, Îles Crozet, Îles Kerguelen, Prince Edward Islands, Réunion), Pacific Islands (Hawaiian Islands, New Zealand), Australia, Antarctica (Deception Island).

Discussion

Racomitrium lanuginosum is widely distributed throughout the Nearctic and Greenland, where it reaches the highest possible latitudes, becoming rare and scattered southwards. It usually occupies habitats of varying moisture regimes, but exhibits a tendency for growing in exposed, dry, and insolated situations. The often extensive and tumid patches of it found on rocks and soil are mostly hoary when dry. This is due to the very long hyaline awns that at once separate it from all other species of the broadly conceived Racomitrium. The shape of the hair-points is unique not only in the Grimmiaceae but among the mosses. Niphotrichum species often have a similar hoary appearance due to their long, papillose, hair-pointed leaves, but they differ from R. lanuginosum in having non-decurrent awns and tall, stout, conical papillae distributed over the leaf cell lumina, as well as large and often decurrent hyaline alar cells.

The laminal papillae of Racomitrium lanuginosum are identical to those of the genus Codriophorus, but species of that genus are usually readily distinguished by their muticous leaves. The only exception is C. varius, which often has pilose leaves but the awns are non-decurrent, smooth to faintly denticulate, and never papillose. Moreover, it has long-cylindric capsules, smooth setae, and very long, 1–1.8 mm peristome teeth, but in general sporophytes are produced infrequently in R. lanuginosum.

References

None.

Lower Taxa

No lower taxa listed.

AuthorRyszard Ochyra + and Halina Bednarek-Ochyra +
Authority(Hedwig) Bridel +
BasionymsTrichostomum lanuginosum +
DistributionGreenland +, Alta. +, B.C. +, Man. +, Nfld. and Labr. +, N.W.T. +, N.S. +, Nunavut +, Ont. +, Que. +, Yukon +, Alaska +, Calif. +, Idaho +, Maine +, Mont. +, N.H. +, Oreg. +, Wash. +, Central America (Costa Rica) +, South America (Argentina +, Chile +, Colombia +, Ecuador +, Peru) +, Europe +, arctic and temperate Asia (including Borneo +, Java +, New Guinea +, Sumatra) +, South Africa +, Atlantic Islands (Azores +, Canary Islands +, Falkland Islands +, Gough Island +, Iceland +, Madeira +, South Georgia +, Tristan da Cunha) +, Indian Ocean Islands (Heard Island +, Îles Crozet +, Îles Kerguelen +, Prince Edward Islands +, Réunion) +, Pacific Islands (Hawaiian Islands +, New Zealand) +, Australia + and Antarctica (Deception Island). +
Elevationlow to high elevations (0-2300 m) +
HabitatDry, exposed areas, mostly with high light
Dry, exposed areas, mostly with high light intensity, acidic or seldom calciferous soil and rocks, boulders, cliffs, ledges, scree and in fellfields, polar tundra and tundra-like barrens in mountains, hummocks in peatland and moorland, over raw earth of bog margins
nd moorland, over raw earth of bog margins +
IllustratorPatricia M. Eckel +
Publication titleMuscol. Recent., suppl. +
ReferenceNone +
Source xmlhttps://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/f6b125a955440c0872999024f038d74684f65921/coarse grained fna xml/V27/V27 403.xml +
SynonymsGrimmia sect. Racomitrium +, Racomitrium sect. Lanuginosa + and Trichostomum sect. Racomitrium +
Taxon familyGrimmiaceae +
Taxon nameRacomitrium lanuginosum +
Taxon parentRacomitrium +
Taxon rankspecies +
VolumeVolume 27 +