BFNA Title: Pseudocalliergon
Author: L. Hedenäs & N. Miller
Date: Feb. 29, 2012
Edit Level: R
Version: 3

Bryophyte Flora of North America, Provisional Publication
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AMBLYSTEGIACEAE- Pseudocalliergon
Edit level R

XX. PSEUDOCALLIERGON (Limpricht) Loeske, Hedwigia 46: 311. 1907 * [Greek pseudo-, false or resembling, and Calliergon, name of a genus of mosses]

Lars Hedenäs

Norton G. Miller†

Hypnum sect. Pseudocalliergon Limpricht, Laubm. Deutschl. 3: 547. 1899 [“Pseudo-calliergon”]

 

Plants medium-sized to robust, sometimes turgid, green, brown-green, yellowish or yellow-brown, often with golden gloss when dry. Stem unbranched to irregularly pinnately branched ± in one plane, with central strand and without a hyalodermis; paraphyllia absent; rhizoids or rhizoid initials only on stem or at abaxial leaf costa insertion, smooth, slightly branched; axillary hairs with 1--2(--3) distal early yellowish or brownish cells, apical cell usually comparatively long. Stem leaves straight and then mostly imbricate or falcate, ovate-lanceolate to broadly ovate, at apex broadly rounded, suddenly narrowed to apiculate point, or gradually to suddenly narrowed to shortly or longly acuminate apex, not plicate, slightly to strongly concave; marginal lamina cells 1-stratose, margin plane, entire or distinctly denticulate; costa single and ending in mid-leaf or beyond, or short and double; median lamina cells linear, smooth or some cells in distal leaf with prorate distal ends on abaxial side; alar cells quadrate to longly rectangular, with yellow walls when mature, thin-walled to strongly incrassate, eporose or porose, inflated or slightly so, in indistinctly delimited transversely triangular group or sometimes in single transverse basal row, decurrent (P. trifarium) or not. Sexual condition dioicous. Inner perichaetial leaves gradually or suddenly narrowed to acuminate or shortly acuminate apex, plicate; margin entire or partly denticulate proximally, more strongly denticulate or with single teeth at shoulder; lamina cells smooth. Capsule cylindric, curved, horizontal or inclined; peristome perfect or almost so; exostome margin weakly dentate above. Spores 10.5--18 \um.

 

Species 5 (4 in the flora): mainly the Holarctic region, but with scattered occurrences farther south.

 

Pseudocalliergon is typical of mineral-rich to strongly calcareous habitats. Excepting P. angustifolium, the shoots are generally turgid, with markedly broad leaves. All species become yellow-brown when old; when they are dry they frequently have a typical golden metallic gloss that is rare only in P. trifarium (readily visible in the dissecting microscope). The alar groups consist of few or often numerous quadrate to longly rectangular cells, often with yellow walls, thin-walled to often strongly incrassate, and form indistinctly delimited transversely triangular groups or sometimes single transverse basal rows. The distal portion of the axillary hairs is mostly of 1--2 cells, of which the apical one is often strikingly elongate. Species of Pseudocalliergon are somewhat similar to those of Drepanocladus, but dry plants of Pseudocalliergon have usually a golden metallic gloss that is absent in Drepanocladus, alar groups are more diffusely delimited and consist of less strongly inflated cells than in the latter, axillary hairs are usually getting yellowish early only in Pseudocalliergon, and habitats of the Pseudocalliergon species are usually nutrient-poor, whereas those of Drepanocladus species are more or less nutrient-rich. Despite morphological distinctness, molecular data suggest that the Pseudocalliergon species are actually nested within Drepanocladus (L. Hedenäs and C. Rosborg 2008). Characters differentiating Pseudocalliergon from Sanionia are mentioned under this genus. Features separating Pseudocalliergon from Hamatocaulis, Loeskypnum, Scorpidium, or Warnstorfia are pointed out in the notes after the Calliergonaceae description.

 

SELECTED REFERENCES Hedenäs, L.1992. The genus Pseudocalliergon in northern Europe. Lindbergia 16: 80--99. 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. Miller, N. G. 1980. Mosses as paleoecological indicators of late glacial terrestrial environments: some North American studies. Bull. Torr. Bot. Club 107: 373--391. 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 falcate, from basal leaf portion gradually or ± suddenly narrowed to shortly or longly acuminate apex.

2. Stem leaves ovate-lanceolate to rather broadly ovate, apex longly acuminate; costa single, 3--5-stratose and (31.5--)38.5--70(--73.5) \um wide near base; distal lamina cells often prorate abaxially; boreal or mountainous species.           1. Pseudocalliergon angustifolium

2. Stem leaves ovate to very broadly ovate, apex shortly to rather longly acuminate; costa single or sometimes branched or double, when single 2--3-stratose and 21--53 \um wide near base; distal lamina cells smooth; Arctic species.       2. Pseudocalliergon brevifolium

1. Stem leaves ± straight, from basal leaf portion suddenly narrowed to apiculate point, or leaf apex broadly rounded.

3. Stem leaves apiculate.           3. Pseudocalliergon turgescens

3. Stem leaves with broadly rounded apex.        4. Pseudocalliergon trifarium

 

1. Pseudocalliergon angustifolium Hedenäs, Lindbergia 16: 85. 1990 [1992]

 

Drepanocladus angustifolius (Hedenäs) Hedenäs & C. Rosborg

 

Plants medium-sized, not turgid, slightly or irregularly pinnately branched, usually with golden gloss when dry. Stem leaves erectopatent to spreading, falcate, ovate-lanceolate to rather broadly ovate, gradually narrowed to longly acuminate, channeled or almost tubular apex; margin partly denticulate or finely denticulate; costa single, ending in acumen, (31.5--)38.5--70(--73.5) \um wide near base, 3--5-stratose; distal lamina cells smooth or often distally prorate abaxially; alar cells rectangular, rarely quadrate, not or slightly inflated, thin-walled or incrassate, in approximately transversely triangular, indistinctly delimited group. Mature perichaetia and sporophyte not known.

 

Mountainous western North America and the Arctic, forested and open habitats, rich fens or shallow, wet depressions on lime-rich ground, sometimes in or close to late snow-bed vegetation; low to high elevations; Greenland; Alta., B.C., N.W.T., Nunavut, Yukon, Alaska, Calif., Colo., Wyo.; n Europe, including e Russia (in Chukotskiy Polustrov); Atlantic Islands (Iceland).

 

Pseudocalliergon angustifolium has usually been confused with Warnstorfia fluitans and the Eurasian and African Drepanocladus sendtneri (Schimper ex H. Müller) Warnstorf. These three species have similar leaf shapes and have relatively small or indistinctly delimited alar groups. Pseudocalliergon angustifolium and D. sendtneri have similarly shaped and commonly incrassate alar cells, and are dioicous. Unlike W. fluitans, the latter two species are usually found in calcareous habitats. Warnstorfia fluitans is separated from the other two by being autoicous, by the frequent occurrence of rhizoid initials or rhizoids on the stem and branch leaf laminae (especially near the leaf apices), by its more strongly inflated alar cells that form groups which reach or almost reach the costa, and by a number of sporophyte and perichaetial characters mentioned under the family description. Drepanocladus sendtneri has often a stronger costa and more sharply delimited alar groups than P. angustifolium. Pseudocalliergon angustifolium differs from both other species in the frequently occurring golden gloss in dry plants, in the usually early yellowish upper parts of the axillary hairs (frequently with a markedly elongate apical cell), and in the often occurring prorate cells in the distal dorsal side of the stem and branch leaf lamina. The differences between P. angustifolium and P. brevifolium are discussed under the latter. Whether the station located by Williams (NY) at Heart Butte in 1897 is located in Montana or North Dakota is unclear.

2. Pseudocalliergon brevifolium (Lindberg) Hedenäs, Lindbergia 16:89. 1990 [1992]

 

Hypnum brevifolium Lindberg, Oefv. K. Vet. Ak. Foerh. 23: 541. 1867; Drepanocladus brevifolius (Lindberg) Warnstorf; D. lycopodioides var. brevifolius (Lindberg) Mönkemeyer; D. latifolius (Lindberg & Arnell) Warnstorf

 

Plants medium-sized, sometimes turgid, usually slightly and irregularly branched, often with golden gloss when dry. Stem leaves erectopatent to patent, falcate or strongly falcate, ovate to very broadly ovate, gradually or somewhat suddenly narrowed to acuminate or rather longly acuminate, channeled or almost tubular apex; margin entire or occasionally partly very finely denticulate; costa either single, extending 60--75% way up leaf, 21--53 \um wide near base and 2--3-stratose, or double and extending 30--40(--50)% way up leaf; distal lamina cells smooth; alar cells rectangular or longly rectangular, inflated, slightly or strongly incrassate, in approximately transversely triangular, indistinctly delimited group. Inner perichaetial leaves gradually or ± suddenly narrowed to acuminate or shortly acuminate apex. Capsule ± horizontal.

 

Mainly on tundra in the Arctic, calcium-rich wetland habitats, rich fens, moist excavated soil, surrounding pools and percolation areas; low to moderate elevations; Greenland; Nfld., N.W.T., Nunavut, Yukon; Alaska; Arctic Eurasia.

 

Pseudocalliergon brevifolium is usually recognized by its yellow-brown, slightly and irregularly branched shoots, its relatively broad, falcate leaves, and its channeled or almost tubular leaf acumen. It could possibly be confused with P. angustifolium, but the latter has more longly and more narrowly acuminate stem and branch leaves. In P. brevifolium the costa is normally single and 3--5-stratose, whereas it is only 2--3-stratose or frequently short and double in the other species. In P. angustifolium the stem and branch leaf margins are at least partly distinctly denticulate or finely denticulate and the distal lamina cells are frequently prorate abaxially, in P. brevifolium the leaf margins are entire or occasionally very finely denticulate and the distal lamina cells are smooth. Pseudocalliergon brevifolium is often distinctly turgid, this not being the case in P. angustifolium.

 

3. Pseudocalliergon turgescens (T. Jensen) Loeske, Hedwigia 46: 311. 1907

 

Hypnum turgescens T. Jensen, Vid. Medd. Naturh. For. Kjoebenh. 1858(1--4): 63. 1858; Calliergon turgescens (T. Jensen) Kindberg; Drepanocladus turgescens (T. Jensen) Brotherus; Scorpidium turgescens (T. Jensen) Loeske

 

Plants robust, more rarely medium-sized, turgid, slightly and irregularly branched, often with golden gloss when dry. Stem leaves imbricate or sometimes ± spreading, straight, ovate or broadly ovate, upwards suddenly narrowed to short apiculus; margin entire or occasionally partly very finely denticulate; costa double and extending 20--40% way up leaf, rarely single and slightly longer; distal lamina cells smooth; alar cells quadrate or rectangular, slightly inflated, incrassate or strongly incrassate, in approximately transversely triangular, indistinctly delimited group. Inner perichaetial leaves gradually or rather suddenly narrowed to shortly acuminate apex. Capsule horizontal to inclined.

 

Mostly open (without forest) habitats, lime-rich wetland habitats, small fens, small depressions in soil or on flat limestone rocks, along rills or on rocks flushed with calcium-rich water, more rarely submerged in small lakes or pools; low to high elevations; Greenland; Alta., B.C., Man., N.B., Nfld., N.W.T., N.S., Nunavut, Ont., Que., Sask., Yukon; Alaska, Colo., Maine, Mass., Mich., Minn., Mont., N.Y., Ohio, Vt., Wyo.; South America (Bolivia, Peru), Eurasia, Africa.

 

Pseudocalliergon turgescens is easily known by its rather robust and usually weakly branched shoots, with straight, imbricate or sometimes slightly spreading, ovate or broadly ovate, apiculate and strongly concave leaves. Except in protected, shaded habitats, it has mostly a yellow or yellow-brown color. The species is often propagated vegetatively by easily detached shoot apices. This species is rather frequently confused with Scorpidium scorpioides, especially the straight-leaved phenotypes of the latter. However, the two are easily separated by the numerous small and incrassate alar cells that form indistinctly delimited alar groups, and the complete lack of a stem hyalodermis in P. turgescens, versus the few, inflated and thin-walled alar cells in sharply delimited groups, and the presence of at least a partial stem hyalodermis in S. scorpioides. Plants of S. scorpioides have often clearly red colors, this never being the case in P. turgescens.

 

4. Pseudocalliergon trifarium (F. Weber & D. Mohr) Loeske, Hedwigia 46: 301. 1907

 

Hypnum trifarium F. Weber & D. Mohr, Naturh. Reise Schwedens 177. 1804; Calliergon trifarium (F. Weber & D. Mohr) Kindberg; Drepanocladus trifarius (F. Weber & D. Mohr) Brotherus ex Paris; Scorpidium trifarium (F. Weber & D. Mohr) H. K. G. Paul

 

Plants medium-sized, rarely almost robust, slightly turgid, unbranched or slightly and irregularly branched, rarely with golden gloss when dry. Stem leaves imbricate or sometimes spreading, straight, broadly or very broadly ovate, with broadly rounded apex; margin entire; costa single, extending 60--90(--95)% way up leaf, 33--69 \um wide near base; distal lamina cells smooth; alar cells longly rectangular, inflated, incrassate or strongly incrassate, in single transverse row or more commonly in approximately transversely triangular, indistinctly delimited group. Inner perichaetial leaves suddenly narrowed to obtuse or acute apex. Capsule horizontal to inclined.

 

Lime-rich and usually deep fens, often as single shoots among other species (especially Scorpidium scorpioides), occasionally rocks with trickling water or spray zones of waterfalls; low to high elevations; Greenland; Alta., B.C., Nfld., N.W.T., Nunavut, Ont.; Alaska, Conn., Mich., Minn., Mont., N.Y., Ohio, Oreg.; West Indies (Dominican Republic); South America (Colombia, Venezuela); Eurasia.

 

Pseudocalliergon trifarium is easily identified by its unbranched or almost unbranched shoots with straight and imbricate or more rarely ± spreading, broadly or very broadly ovate leaves with broadly rounded apices. Shoots of P. trifarium are frequently divided into segments that correspond with growth seasons. In the proximal, spring portion of each segment the leaves are smaller and more strongly imbricate than distally in the same segment. The transition between the differently sized leaves is gradual within each segment, whereas the transition between segments is sudden. This species could possibly be confused with Loeskypnum wickesiae, and the characters separating these two species are given with the latter.

 

OTHER REFERENCES

 

Hedenäs, L. and C. Rosborg. 2008 [2008]. Pseudocalliergon, an ingroup in Drepanocladus (Bryophyta: Amblystegiaceae). Lindbergia 33: 67--74.