BFNA Title: Sarmentypnum
Author: L. Hedenäs 
Date: March 20, 2008
Edit Level: R 
Version: 1c (3)

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden

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xxx. SARMENTYPNUM Tuomikoski & T. J. Koponen, Ann. Bot. Fennici 16: 223. 1979 * [The epithet sarmentosum, and Hypnum, a genus name]

Lars Hedenäs


Plants medium-sized to rather large, green, yellow-green, brownish, red-brown or with clear red colors. Stem sparsely to richly radially branched, with central strand and without or sometimes with a partial outer hyalodermis, cells within cortex thin-walled; outer pseudoparaphyllia broad, triangular to broader than long and often irregular in outline; rhizoids or rhizoid initials at various points on the leaves, or on scattered points or in rows on the stem; axillary hairs with 1--7 distal hyaline or early brown cells. Stem leaves straight or falcate, triangular to ovate or narrowly ovate, either gradually narrowed to a long-acuminate, acuminate or obtuse apex, or suddenly narrowed to a shortly acuminate to broadly rounded and usually apiculate apex, not or indistinctly plicate, concave or strongly concave; margin entire, sinuous or denticulate; costa single, ending ca. 60% way up leaf to long-excurrent; median lamina cells incrassate or thin-walled, eporose to porose; alar cells quadrate or shortly to long-rectangular, hyaline and thin-walled, or, especially near costa or when old, red or brown and incrassate, inflated or strongly inflated, in transversely triangular group, distinctly delimited from surrounding cells, not or hardly decurrent, or in S. tundrae long-and broadly decurrent. Sexual condition dioicous. Inner perichaetial leaves not plicate; vaginula naked. Capsule curved and ± horizontal; lacking a separating annulus; exostome reticulate on proximal exterior, margin dentate distally. Spores 11--24 \um.


Species 7 (5 in the flora): widespread.


The leaves of Sarmentypnum species are either moderately curved to straight and gradually narrowed to the apex, or straight and suddenly narrowed to a usually apiculate apex. Red colors are frequent in several species, and the leaves are non-decurrent in all except S. tundrae. The alar groups are transversely triangular and consist of inflated, and (at least when young) usually hyaline cells. Except for S. tundrae, Sarmentypnum species typically occur in intermediately mineral-rich fens. Most species are found in nutrient-poor habitats, but S. tundrae grows in somewhat nutrient-rich places. Sarmentypnum and Warnstorfia are well separated based on molecular evidence, and morphological features differentiating the two are mentioned under the latter genus. Sarmentypnum collections with falcate leaves and lacking sporophytes or red pigments are frequently confused with falcate-leaved species with transversely triangular alar groups in the Drepanocladus aduncus complex. The frequently present rhizoid initials occurring close to leaf apices in all  Sarmentypnum species except S. trichophyllum (in which they are rare) are very helpful in differentiating these from Drepanocladus species, which always lack such initials. In addition, Sarmentypnum species are usually radially branched, the leaves generally give an "ordered" impression when viewing entire plants, and the distal portion of the axillary hairs frequently consists of more than two cells. Drepanocladus species are distichously branched, their leaves give a more unordered impression, and their axillary hairs have almost invariably only one or two distal cells, except D. polygamus, which has 1--3 differentiated hyaline distal cells. When sporophytes are present, the numerous sporophytic and perichaetial characters mentioned in the introduction to the family make the separation of these taxa easy.


SELECTED REFERENCES Hedenäs, L. 1993. A generic revision of the Warnstorfia-Calliergon group. J. Bryol. 17: 447--479. Hedenäs, L. 2006. Additional insights into the phylogeny of Calliergon, Loeskypnum, Straminergon, and Warnstorfia (Bryophyta: Calliergonaceae). J. Hattori Bot. Lab. 100: 125--134. Janssens, J. A. 1983. Past and extant distribution of Drepanocladus in North America, with notes on the differentiation of fossil fragments. J. Hattori Bot. Lab. 54: 251--298. Wynne, F. E. 1944. Studies in Drepanocladus. IV. Taxonomy. Bryologist 47: 147--189. Wynne, F. E. 1945. Studies in Calliergon and related genera. Bryologist 48: 131--155.


1. Stem leaves long- and broadly decurrent; plants never red........ 1. Sarmentypnum tundrae

1. Stem leaves not or hardly decurrent; plant color variable, often with red colors present.

2. Stem and branch leaves with short- or long-excurrent costa; branch apices (and often shoot apex) of tightly convolute leaves ; axillary hairs 2--7-celled, abundant, early becoming brown.
 . . . 3. Sarmentypnum trichophyllum

2. Leaf costa not excurrent; branch and shoot apices not pencil-like; axillary hairs 1--4(--5)-celled, abundant or not, hyaline when young.

3. Stem leaves oblong or ovate, at apex rounded, or ± suddenly narrowed to acute or very slightly acuminate apex, with short apiculus (sometimes lost in old leaves).
....................................................................... 5. Sarmentypnum sarmentosum

3. Stem leaves gradually narrowed to acuminate apex from an ovate, ovate-lanceolate or ovate-triangular; apiculus absent.

4. Stem leaves falcate or straight; leaf margin distinctly denticulate distally or proximally or both; marginal basal cells usually differentiated from the median cells (least distinct in submerged plants), often rectangular or distinctly widened and forming distinct border; leaves concave and acumen sometimes furrowed but not strongly so .
.......................................................... 2. Sarmentypnum exannulatum

4. Stem leaves straight or almost so, erect; leaf margin entire or at most  very finely, obtusely denticulate; marginal cells at widest part of leaf usually similar to the cells farther in, rarely slightly differentiated. Leaves strongly concave, acumen deeply furrowed (rare Arctic species).
4. Sarmentypnum pseudosarmentosum


1. Sarmentypnum tundrae (Arnell) Hedenäs, J. Hattori Bot. Lab. 100: 133. 2006


Amblystegium tundrae Arnell in Lindberg and Arnell, K. Svensk. Vet. Ak. Handl. 23(10): 128. 1890; Drepanocladus exannulatus var. tundrae (Arnell) Warnstorf; D. tundrae (Arnell) Loeske; Warnstorfia tundrae (Arnell) Loeske


Plants medium-sized, green, yellowish or brownish, never red; branch and shoot apices not of convolute leaves; cells of stem epidermis not differentiated; axillary hairs with 1--2-celled distal portion, hyaline when young. Stem leaves slightly falcate or  straight, from ovate or ovate-triangular base gradually narrowed to  a broadly acuminate and often hooked apex , slightly concave; margins denticulate proximally, entire or sparsely denticulate distally; costa ending 70--85% of the way up the leaf; alar cells in distinctly delimited, transversely triangular groups   almost reaching the costa, longly and broadly decurrent.


Mineral and somewhat nutrient-rich fens and on shores, occasionally submerged in lakes; 0--1560 m; Greenland; Alta., B.C., Man., Nfld., N.W.T., Nunavut, Ont., Que., Yukon; Alaska, Maine, Wyo.; n Eurasia; incorrectly reported from Australia.


Sarmentypnum tundrae shares no morphological apomorphies with the other species in Sarmentypnum or with those in Calliergon, which are the two possible generic choices for these species based on morphology. It is here included in Sarmentypnum from molecular evidence. Sarmentypnum tundrae differs from all other members of the genus by its longly and more or less broadly decurrent stem leaves. Additional features that aid in separating this species from S. exannulatum and S. procerum are the rather weakly falcate stem leaves and the total lack of red colors.


2. Sarmentypnum exannulatum (Schimper) Hedenäs, J. Hattori Bot. Lab. 100: 132. 2006


Hypnum exannulatum Schimper, Bryol. Eur. 6: 110. fig. 603. (fasc. 57--61, Mon. 34. 23) 1854; Drepanocladus exannulatus (Schimper) Warnstorf; D. exannulatus var. purpurascens (Schimper) Herzog; D. exannulatus var. rotae (De Notaris) Loeske; Warnstorfia exannulata (Schimper) Loeske; W. exannulata var. purpurascens (Schimper) Tuomikoski & T. J. Koponen


Plants medium-sized, green, yellowish, or with red secondary coloration; branch and shoot apices not pencil-like; cells of stem epidermis usually widened to form a partial hyalodermis; axillary hairs with 1--4-celled distal portion, hyaline when young. Stem leaves falcate or strongly so, more rarely straight, gradually narrowed to acuminate apex from an ovate or ovate-triangular base, concave; margins distinctly denticulate  distally or proximally or both; costa ending 60--95% of the way up the leaf; alar cells in a distinctly delimited, transversely triangular group that reaches costa or almost so, not decurrent.


Intermediately mineral-rich fens, often around springs or in late snow-beds, sometimes submerged in lakes; 0--4150 m; Greenland; Alta., B.C., Man., N.B., Nfld., N.W.T., N.S., Nunavut, Ont., Que., Sask., Yukon; Alaska, Calif., Colo., Idaho, Maine, Md., Mass., Mich., Minn, Mont., Nev., N.H., N.Y., Oreg., Pa., Utah, Wash., Wyo.; Mexico; South America; Eurasia; Africa; Australia; Pacific Islands (New Zealand).


Among the wetland species with leaves that narrow gradually to the leaf apex and are gradually curved throughout, Sarmentypnum exannulatum is one of the most frequent. In S. exannulatum, the marginal lamina cells in the widest part of the stem leaves are often distinctly rectangular or distinctly widened or both. This is never as pronounced in other Sarmentypnum species as it can be in S. exannulatum. However, because this feature is rather variable it should be used with caution when identifying material. Warnstorfia fluitans and W. pseudostraminea differ from S. exannulatum in being autoicous, having mainly narrowly triangular to lanceolate pseudoparaphyllia, hardly ever with pure red colors, and with more weakly differentiated alar groups. The alar groups in W. fluitans are usually narrower, i.e., reaching less far distally in the leaf than in is the case with S. exannulatum, whereas those in W. pseudostraminea often form ovate groups together with the supra-alar cells. Certain phenotypes of S. exannulatum from springs, with inflated alar cells more or less in only one row along the leaf base, have been called W. exannulata var. purpurascens. However, transitions between these phenotypes and those from other habitats exist, and if the different phenotypes are cultivated together the resulting plants cannot be separated from each other (based on north European material). Modifications with less well-delimited alar cells do occur. The only difference mentioned in the literature between the most common expressions of Sarmentypnum exannulatum and straight-leafed forms, which have been called “orthophyllus Mönkemeyer,” is in the leaf curvature. Although the type of the latter was not seen, a separate taxon cannot be recognized for straight-leaved plants.


3. Sarmentypnum trichophyllum (Warnstorf) Hedenäs, J. Hattori Bot. Lab. 100: 133. 2006


Drepanocladus rotae var. trichophyllus Warnstorf, Krypt. Fl. Brandenburg 2: 1049. 1906; D. trichophyllus (Warnstorf) Podpěra; Warnstorfia trichophylla (Warnstorf) Tuomikoski & T. J. Koponen


Plants medium-sized or rather large, green, brown, or when emergent above water surface with red secondary coloration; branch apices (and often shoot apex) ± aciculate by long-convolute leaves; cells of stem epidermis not widened, or occasionally in small parts (less than 10% of circumference) slightly widened; axillary hairs with 2--7-celled distal portion, early brown. Stem leaves straight or more rarely falcate, gradually narrowed to a long- or usually very long- acuminate apex from an ovate to triangular base, concave; margins denticulate; costa strong, short- or long- excurrent (excurrent portion up to 1/3 leaf length); alar cells in distinctly delimited, transversely triangular group that reaches costa, not decurrent.


Normally submerged or floating in mineral-rich water, but with a relatively high pH (5.1--6.7 in Europe), mostly in small lakes, water-filled kettle holes, ox-bows and other small aquatic habitats; 0--250 m; Man., Nunavut; w Alaska; South America (Colombia), n Eurasia.


Sarmentypnum trichophyllum is occasionally reminiscent of S. exannulatum, but its distinctly acicular branch and shoot apices, excurrent costa and long, early brown axillary hairs (shorter and normally hyaline in S. exannulatum) separate them. For the differences between Sarmentypnum trichophyllum and Drepanocladus longifolius, see the note after the latter.  Sarmentypnum trichophyllum has been reported from many areas of Canada (R. R. Ireland et al. 1987). The species, however, seems to be widespread only in western Alaska, and few specimens from outside this area have proved to belong to this species. It was reported from two localities in Greenland by G. Mogensen (1995), but specimens that this report is based on are S. exannulatum. In northern Europe, S. trichophyllum has been found at higher altitudes (750 m) and there is no reason to assume that the species is restricted to lower elevations in North America.


4. Sarmentypnum pseudosarmentosum (Cardot & Thériot) Hedenäs, J. Hattori Bot. Lab. 100: 133. 2006


Hypnum pseudosarmentosum Cardot & Thériot, Univ. California Publ. Bot. 2: 305, plate 27, fig. 2. 1906; Calliergon pseudosarmentosum (Cardot & Thériot) Brotherus; Drepanocladus pseudosarmentosus (Cardot & Thériot) Persson; Warnstorfia pseudosarmentosa (Cardot & Thériot) Tuomikoski & T. J. Koponen


Plants medium-sized, with red secondary coloration (entirely green plants not seen); branch and shoot apices not acicular; cells of stem epidermis widened in part of stem circumference and forming a partial hyalodermis; axillary hairs with 1--3-celled distal portion, hyaline when young. Stem leaves straight and erect or weakly homomallous, gradually narrowed to an acuminate or  sometimes blunt apex from an ovate or triangular-ovate base, apex sometimes hooked, concave,  channeled to almost tubular near apex; margins entire or at most in part minutely, obtusely denticulate; costa ending shortly below leaf apex; alar cells in distinctly delimited, transversely triangular group that reaches costa or almost so, not decurrent.


In apparently spring-influenced habitats or along the shores of brooks; 0--1700 m; Nunavut, Yukon; Alaska; endemic to North America.


Sarmentypnum psuedosarmentosum is superficially similar to Sarmentypnum sarmentosum in habit, with rather thick shoots and short and often curved branches with obtuse endings due to densely inserted and relatively short-acuminate leaves. The leaves, however, are more gradually narrowed than in S. sarmentosum, and the usually acuminate or short-acuminate leaf apices in the first of these species make the separation easy. Sarmentypnum pseudosarmentosum is close to S. exannulatum, from which it differs mainly in the more strongly concave leaves that are mostly deeply furrowed to almost tubular distally, and in its entire leaf margins. Sometimes the stem leaf lamina is weakly plicate (when moist) in S. pseudosarmentosum, which does not occur in S. exannulatum. Few specimens of S. pseudosarmentosum were available for study and it is therefore difficult to judge its status. It may be a good species, or it may represent an extreme, Arctic modification of S. exannulatum.


5. Sarmentypnum sarmentosum (Wahlenberg) Tuomikoski & T.J. Koponen, Ann. Bot. Fennici 16: 223. 1979


Hypnum sarmentosum Wahlenberg, Fl. Lapp. 380. 1812; Calliergon sarmentosum (Wahlenberg) Kindberg; C. sarmentosum var. beringianum (Cardot & Thériot) Grout; C. sarmentosum var. fallaciosum (Milde) G. Roth; C. sarmentosum var. fontinaloides (Berggren) G. Roth; Warnstorfia sarmentosa (Wahlenberg) Hedenäs


Plants medium-sized, with red or dark red secondary coloration, sometimes green; branch and shoot apices not pencil-like; cells of stem epidermis not widened; axillary hairs with 1--4(--5)-celled distal portion, hyaline when young. Stem leaves straight, loosely imbricate or erect-spreading, oblong, ovate or narrowly ovate, distally ± suddenly narrowed to a rounded- or acute-apiculate apex, the apiculus (rarely absent) often bent inwards over leaf, concave; margins entire or nearly so; costa ending 80--95% of way up leaf; alar cells in a distinctly delimited, transversely triangular group that gradually passes into strongly incrassate cells near costa, not or hardly decurrent.


Intermediately mineral-rich fens, often around springs or in late snow-beds, sometimes submerged in lakes; 0--3960 m; Greenland; Alta., B.C., Man., Nfld., N.W.T., Nunavut,  Ont., Que., Yukon; Alaska, Colo., Mont., N.H., N.Y., Wash., Wyo.; South America, Eurasia (including Papua New Guinea), e Africa, Australia, Pacific Islands (New Zealand), Antarctica.


Sarmentypnum sarmentosum is easily separated from other North American species of the genus by its oblong or ovate stem leaves, suddenly narrowed to a rounded- or acute-apiculate  apex. The apiculus is most distinct in young leaves and is rarely completely lacking, but may be eroded in older leaves. In late snow beds or in cold springs in higher mountains and in the Arctic, modifications with less well-delimited alar cells occur. The species could perhaps be confused with Calliergon species, which, however, are larger, have broader leaves and never have a clear red color, or with Straminergon stramineum, which is usually pale or whitish green to yellow-green (never red) and lacks the apical apiculus . The latter species is more sparsely branched (sometimes unbranched) than S. sarmentosum, and in addition the alar groups are ovate or broadly ovate in Straminergon, transversely triangular in S. sarmentosum. The type material of Calliergon subsarmentosum Kindberg. (Vancouver Island) is taxonomically Calliergon giganteum.


Sarmentypnum sarmentosum was earlier placed in the genus Calliergon because of general similarities in leaf shape and orientation. However, in the frequent presence of red pigments, appearance of the alar groups, nondecurrent leaves, general size of the plants, and in its habitat preferences it is more similar to  Sarmentypnum species, such as S. exannulatum. In addition, the differences between S. sarmentosum and S. exannulatum are bridged by the South American Sarmentypnum luipichense (R. S. Williams) Hedenäs, which is closely related to S. sarmentosum but has leaves  more gradually narrowed to the apex and more or less denticulate leaf margins, and S. pseudosarmentosum, which, despite a leaf shape that is similar to that in straight-leaved specimens of S. exannulatum is reminiscent of S. sarmentosum in its habit and entire leaf margins. Morphology does not justify an exclusion of S. sarmentosum from the genus, and recent molecular results also support the present treatment of the species.


Sarmentypnum procerum (Renauld & Arnell) Hedenäs (Drepanocladus procerus (Renauld & Arnell) Warnstorf), is widespread and rather common in the Boreal Zone of northern Europe, and, though unknown in North America, may be expected. It is usually strongly red or blackish red, has strongly concave and in distal portion furrowed leaves, entire or almost entire leaf margins, and lacks the partial hyalodermis that is present in the two closely related species S. exannulatum and S. pseudosarmentosum. Sarmentypnum procerum occurs in slightly more mineral-poor habitats than the latter two, often in flarks.




Ireland, R. R., Brassard, G. R., Schofield, W. B. and Vitt, D. H. 1987. Checklist of the mosses of Canada II. Lindbergia 13: 1--62.


Mogensen, G. 1995. Warnstorfia trichophylla (Warnst.) Tuom. et T. Kop., a bryophyte new to Greenland (Musci, Amblystegiaceae). Lindbergia 20: 3--4.