Sphagnum incundum Flatberg & Hassel, 2018

Kyrkjeeide, Magni Olsen, Hassel, Kristian, Shaw, Blanka, Shaw, A. Jonathan, Temsch, Eva M. & Flatberg, Kjell Ivar, 2018, Sphagnum incundum a new species in Sphagnum subg. Acutifolia (Sphagnaceae) from boreal and arctic regions of North America, Phytotaxa 333 (1), pp. 1-21 : 14-18

Sphagnum incundum Flatberg & Hassel sp. nov. ( Figures 8–9 )

Type :— Canada. Quebec: Nunavik. Ivujivik, 27 m a.s.l., 62°24’50.2”N, 77°54’39.6”W, leg. Bergfrid & Kjell I. Flatberg 4 Aug 2007, Flatberg 314-07, TRH B-9718. Holotype TRH; isotypes: LE, DUKE, QFA. Habitat: Intermediate, slightly sloping arctic fen.

Diagnosis:— Sphagnum incundum is in macro-morphology recognized by slender shoots with predominantly brown-orange to purple-red capitula and straight and non-recurved leaves on innermost capitulum branches on dry plants. In micro-morphology, it is foremost recognized by narrowly lingulate stem leaves with acute to acute-obtuse apices, strongly S-shaped stem leaf hyalocysts with common occurrence of faint fibrils in distal leaf-parts, and divergent branch leaf hyalocysts on distal end convex surfaces with pores usually occupying between 1/3 and 1/2 of cell width. The new species is gametophytic haploid and closely allied morphologically to S. flavicomans , S. subfulvum , and S. subnitens .

Sphagnum subg. Acutifolia sect. Acutifolia . Gametophytic plants haploid, varyingly medium-sized. Capitulum ( Figure 8 ) rather flat, indistinctly 5-parted from above. Predominantly pale brown-orange usually with distinct tinge of purple-red ( Figure 8 ), sometimes markedly so in exposed habitats, to more greenish brown in more shaded habitats. Capitulum branches rather straight to varyingly incurved with acute-obtuse ends. Leaves on innermost branches in dry capitula narrowly tapering above and non-recurved. Terminal bud inconspicuous and often hidden by innermost branches. Stem greenish in upper part, pale brownish in lower parts; in transverse sect. with markedly differentiated, (2–)3–4(–5) cells wide cortex of large cells ( Figure 9C ), and with a brownish sclerodermis of small, incrassate cells 3– 6 cells wide, and a central medulla of large, thin-walled cells; stem cortex in superficial view ( Figure 9C ) non-porose. Stem leaves ( Figure 9A ) erect-patent to erect-appressed to the stem, narrowly lingulate to less commonly lingulate-triangular and sometimes somewhat involute above. Apex narrowly acute to obtuse and somewhat truncate. Border in distal half of leaf narrow, 2–4 cells wide, in proximal part widened and filling up 1/3 to 1/2 of baseline width. Mean length (n=25) 1.53 mm ± 0.08 mm (min–max: 1.14–1.67 mm), mean mid-leaf breadth 0.68 mm ± 0.06 mm (min–max: 0.54–0.68 mm): Hyalocysts in distal portion of leaves narrowly and distinctly S-shaped, in proximal portion more elongate-S-shaped, markedly larger and wider towards middle portion proximal end, efibrillose to rather commonly with some or sometimes many cells faintly fibrillose (mainly present on convex leaf surface) in distal 1/3(–1/2) of leaf, non-porose or sometimes with some cells close to distal end with one ± circular to elongate membrane gap pore, short hyalocyst close to baseline sometimes with one, large ± circular pore, with a mixture of non-septate and predominantly 2-septate cells, sometimes some cells divided in 3 to 4 parts; chlorocysts rather straight into slightly S-shaped. Branch fascicles moderate distantly crowded, of usually two divergent and one (rarely two) pendent branches. Divergent branches 7–12 mm long, rather straight to somewhat curved, varyingly orientated from stem dependent on growth form, shoots in dense cushions with patent-incurved branches. Pendent branch(es) about equally long as divergent ones, markedly thinner and paler and mostly covering the stem; cortex of divergent branches unistratose and dimorphic, retort cells with somewhat protruding neck. Divergent branch leaves non-ranked and straight to slightly secund in proximal part of branches, non-recurved when dry. Leaves from the middle of branches ovate-lancolate, evenly to rather abruptly tapering above ( Figure 9E ), mean length (n=25) 1.46 mm ± 0.14 mm (min–max: 1.17–1.78 mm), mean mid-leaf breadth 0.56 mm ± 0.09 mm (min–max: 0.44–0.74 mm). Hyalocysts in distal portion of leaf narrowly S-shaped, in proximal portion with wider outline and towards leaf base more elongate ( Figure 9B ). Hyalocysts on distal end convex portion of leaf 111.0 ± 20.9 μm long, 14.2 ± 3.3 μm wide (mean of 75 cells), with 3–8(–10), elliptic to semi-circular, perfect, mostly ringed pores at cell ends and along commissures. Commissural pores usually filling up less than 1/2 of cell width, pores now and then rather small, circular and free-lying; in mid-median portion with 2– 4(–6) elongate-elliptic, perfect and ringed pores along the commissures. Towards leaf margins more widely elliptic to semi-circular, and towards proximal leaf end with 1–2, ± circular and large pores filling out half or more of cell width. Hyalocysts on concave surface in median leaf portions non-porose to some cells with 1(–2), large, circular, perfect and ringed, mostly somewhat free-lying pores filling out 1/2–2/3 of cell width, increasing in number towards leaf margins with usually (3–)4–6 similar pores; hyalocysts in transverse section markedly bulging on convex surface. Branch leaf chlorocysts in superficial view varyingly straight to somewhat S-shaped; in transverse sect. isosceles triangular to triangular-rectangular, in lumen shape with apical end mostly reaching convex surface. Border of leaves narrow, 2–4 cells wide, without resorption furrow. Leaves of pendant branches smaller and narrower than on divergent branches, with more elliptic shape of the commissural pores on distal convex surface ( Figure 9O ), and with several large circular pores in median portions of the concave leaf surface.

Sexual status: Uncertain, but seemingly dioicous or andro-polyoicous. Female plants with sporophytes and without observed antheridial branches ( Canada. Inukjuak, TRH B-9993, B9994, B9998, B9999; Greenland. Ilulissat, TRH B-9981; USA. Alaska, Flatberg TRH B-9986). Male plants with antheridial branches, without sporophytes ( Greenland. Ilulissat, TRH B-9983).

Male plants with short divergent antheridial branches with brownish clavate ends. Perigonial leaves ovate ( Figure 9P ), smaller than ordinary leaves; hyalocysts with pore structure similar to that of divergent branch leaves, but with more circular pores on their concave leaf surface, and with only weakly fibrillose cells towards proximal leaf end. Stem leaves more lingulate in shape and with more obtuse apices than in female plants.

Perichaetial leaves ( Figure 9Q ) varyingly broadly ovate-elliptic to lingulate along the pseudopodium, with broadly obtuse to ± tubularly innrolled apex; hyalocysts narrowly S-shaped to elongate, non-porose and efibrillose, with some cells septate in 2–3 parts.

Capsules dark brown and ± globose. Spores ( Figure 9R ) yellowish brown to golden brown in mass, (24–)26–27(– 29) μm in diameter; on the outer surface coarsely granulate-verrucose with sometimes markedly protruding verrucae.

Etymology:—The specific epithet is derived from the Latin adjective incundus = pleasant, agreeable, delightful.

Distribution:—West Greenland, Canada in Quebec, Nunavut and North West territories, and U.S. A in Alaska. Currently known from the northern boreal to middle arctic vegetation zone.

Ecology:— Sphagnum incundum in arctic localities in West Greenland, and Nunavik, Quebec, occurs in arctic mires on shallow peat in intermediate and rich fens, partly forming small mats and low cushions on gently sloping, soligenous mire, partly growing in small patches on lawn and carpet mire. The most commonly associated sphagna in both regions were S. concinnum (Berggr.) Flatberg (2007: 88) , S. squarrosum , S. teres and S. warnstorfii Russow (1886: 315) . In the boreal Anchorage area, Alaska, it was found growing in a large fen mire on high lawn patches in topogenous, varyingly intermediate to rich fen vegetation, associated with S. papillosum Lind. (1872: 280) , S. subfulvum and S. miyabeanum Warnstorf (1911: 321) . In Bethel area, Alaska, it occurred scattered on intermediate fen lawns in tundra mire.

Specimen list:— W GREENLAND: Qaasuitsup. Ilulissat, Typilak Island, Egedesminne [=Tupilak Island, Aasiaat], [68.70000°N 52.93333°W], Holmen 16975 ( S) ; id. Christianshåb [= Qasigiannguit], [68.820144°N 51.193242°W], Holmen 15450 ( S) ; id. Jakobshavn [= Ilulissat], [69.216667°N 51.10000°W], 1870 Berggren ( S, UPS), Holmen 12120 ( S), 16986 ( UPS) ; id. Ilulissat, S of the village, along the track to Seqinniarfik , 69.206°N 51.1205°W, ca. 70 m, 17 Jul 2006 Flatberg 186-06 ( TRH B-9984), 190-06 ( TRH B-9981) ; id. Ilulissat, S of the village, 69.2078°N 51.129°W, ca. 60 m, 17 Jul 2006 Flatberg 199-06 (with sporophytes ( TRH B-9981) ; id. NE of the village, 69.2111°N 51.0701°W ca. 90 m, 17 Jul 2006 Flatberg 215-06 (male plants) ( TRH B-9983), 216-06 ( TRH B-9982) ; id. Sermersooq, Nuuk, E of the church yard N of Grønlands Naturinstitutt, 64°11’31,78’’N 51°41’44,83’’W, 1–25 m, 15 Aug 2010 K. Hassel, T. Prestø ( TRH B-693795) ; id. Ritenbenk, 69.767°N 51.317°W, 1870 Berggren ( S, UPS) .

CANADA: Quebec. Nouveau-Quebéc, Rivère aux feuilles, 58°15’N 72°W. 16 Jul 1978, L. Couillard 658 ( TRH B-35435) ; id. Lac Minto, Péninsule, 57°16’13’’N 75°01’28’’W, 600 ft, 23 Jul 1975, R. Gauthier 5239, A. Légère ( TRH B-35430) ; id. Nunavik, 300 m à l’est de la rivière Kimber et 9 km au nord-ouest du lac Charlery , 61°3’27’’N 72°26’48’’W, 340 m, 28 Jul 2011, L. Couillard, D. Bérubé ( TRH B-773451) ; id. Inukjuak, 58°27.109’N 78°07.173’W, 10 m, 14 Aug 2007 B. Flatberg, K. I. Flatberg 441-07 ( TRH B-9989, 9990), 442-07 ( TRH B-9988, 9991), 451-07 ( TRH B-9998, 9999), 452-07 TRH B-9996, 9997), 460-07 (with sporophytes) ( TRH B-9992, 9995), 462-07 (with sporophytes) ( TRH B-9993, 9994) ; id. Ivujivik, 62°24.321’N 77°54.855’W, 77 m, 3 Aug 2007 B. Flatberg , K. I. Flatberg 299-07 ( TRH B-38513, 38514) ; 62°24.837’N 77°54.660’W, 27 m, 4 Aug 2007 B. Flatberg, K. I. Flatberg 314-07 ( TRH B-9718 (type), 317-07 ( TRH B-38509), 319-07 ( TRH B-38510, 38511), 320-07 ( TRH B-38508, 38512), 339-07 ( TRH B-38503, 38506, 10000), 340-07 ( TRH B-38504, 38505), 342-07 ( TRH B-38501, 38502) ; 62°23.273’N 77°52.646’W, 5 Aug 2007 B. Flatberg , K. I. Flatberg 343-07 ( TRH B-38515, 38516) ; id. Nunavut. Baker Lake, 64.318056°N 96.0175°W, Duitilly 478 ( MICH, NY) ; id. Northwest Territories. Mackenzie District, Virginia Falls, South Nahani River , 61°38’N 125°42’W [= 61.633333°N 125.700000°W], Marsh 4557 ( NY) .

U.S.A.: Alaska. Alaska Peninsula, Marsh, Naknek , Lepage 22642, 22663 ( MICH), [58.739722°N 156.971667°W] ; id. Anchorage area. Baxter Bog Park between Baxter Rd. and Patterson St., 61°11’30.3’’N 149°45’28.7’’W, 70 m, 5 Aug 2008 Flatberg 128-08 (with sporophytes) ( TRH B-9986), 138-08 ( TRH B-9987), id., near surroundings of the village Bethel, 60°47’N 161°49’W, ca. 20–25 m, 18 Aug 2001 Flatberg 652-01 ( TRH B-741566, 741567) ; id. Colville River, Umiat , 69°22’N 152°08’W [69.366944°N 152.144167°W], 2 Aug 1960 Steere, Holmen, Mårtensson (Bryoph. Arctica Exsicc. 30) ( H, MICH, S) .

Figures

FIGURE 8. Sphagnum incundum in field surface view. A: The type collection including selected holotype and isotypes. Collected in Ivujivik, Quebec, Canada, in intermediate, slightly sloping arctic fen. Photo by K. I. Flatberg, 4 July 2007. Flatberg 314-07 (TRH B-9718). B: Together with S. squarrosum, both with young sporophytes. From Inukjuak, Quebec, Canada, in topogenous, rich fen lawn in arctic mire. Photo by K. I. Flatberg, 14 August 2007. Flatberg 451-07 (TRH B-9999).

FIGURE 9 (part 1). Microscopic pictures of different morphological characters in Sphagnum incundum. A: Stem leaf shapes, B: Stem leaves distal part, C: Stem in transverse sect., D: Stem cortex in superficial view, E: Leaves from middle part of divergent branches, F: Pendent branch leaf, G: Branch leaves in transverse sect., H: Retort cell of branch cortex in superficial view, I: Branch in transverse sect., J–L: Cell structure on convex surface of divergent branch leaves.–J: Distal end portions.–K: Mid-median portion.–L: Proximal end portion. Material (TRH): A: B-9998, 9981, 9718, 693715, B: B-9981, 9998, C: B-38507, D: B-9987, E: B-9998, 9718, F–I: B-9718, J: B-38515, K–L: B-9981.