Compilation
Racomitrium lanuginosum

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Name

Identification
Racomitrium lanuginosum (Hedw.) Brid. [family GRIMMIACEAE ] (stored under name); Racomitrium senile Schimp. [family GRIMMIACEAE ] Verified by Dale Hadley Vitt, Racomitrium lanuginosum (Hedw.) Brid. [family GRIMMIACEAE ] Verified by Juan Larraín, Racomitrium lanuginosum (Müll.Hal.) Vitt & C.Marsh [family GRIMMIACEAE ] Verified by Halina Bednarek-Ochyra, Racomitrium lanuginosum (Müll.Hal.) Vitt & C.Marsh [family GRIMMIACEAE ] Verified by Ryszard Ochyra,
Related name
  • Racomitrium heterostichum
  • Racomitrium sp.
  • Racomitrium geronticum
  • Racomitrium pruinosum
  • Racomitrium curiosissimum
  • Bryum hypnoides
  • Bucklandiella curiosissima
  • Grimmia chrysoblasta
  • Racomitrium austrocanescens
  • Racomitrium lanuginosum
  • Racomitrium incanum
  • Racomitrium senile
  • Racomitrium patagonicum
  • Racomitrium puccioanum
  • Trichostomum lanuginosum

Flora

Entry for Racomitrium lanuginosum (Hedwig) Bridel [family ]
Herbarium
Flora of North America (FNA)
Collection
Flora of North America
Resource Type
Reference Sources
Entry From
Flora of North America, Vol 27,
Names
Racomitrium lanuginosum (Hedwig) Bridel [family ], Muscol. Recent., suppl., 4: 79. 1818,
Trichostomum lanuginosum Hedwig [family ], Sp. Musc. Frond., 107. 1801
Treatment Author(s)
Ryszard Ochyra
Halina Bednarek-Ochyra
Information
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.
Altitude range
low to high elevations (0–2300 m);
Distribution
GreenlandCentral America (Costa Rica)South America (Argentina, Chile, Colombia, Ecuador, Peru)EuropeSouth America (Argentina, Chile, Colombia, Ecuador, Peru) arctic and temperate Asia (including Borneo, Java, New Guinea, Sumatra)South AfricaSouth America (Argentina, Chile, Colombia, Ecuador, Peru) arctic and temperate Asia (including Borneo, Java, New Guinea, Sumatra) Atlantic Islands (Azores, Canary Islands, Falkland Islands, Gough Island, Iceland, Madeira, South Georgia, Tristan da Cunha)South America (Argentina, Chile, Colombia, Ecuador, Peru) arctic and temperate Asia (including Borneo, Java, New Guinea, Sumatra) 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)South America (Argentina, Chile, Colombia, Ecuador, Peru) arctic and temperate Asia (including Borneo, Java, New Guinea, Sumatra) 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)AustraliaAntarctica (Deception Island).USA AlaskaUSA Calif.USA IdahoUSA MaineUSA Mont.USA N.H.USA Oreg.USA Wash.Canada Alta.Canada B.C.Canada Man.Canada Nfld. and Labr.Canada N.W.T.Canada N.S.Canada NunavutCanada Ont.Canada Que.Canada Yukon
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.

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