Scapania nemorosa
Jungermannia nemorosa L., Spec. P1. p. 1132. 1753.
Martinellius nemorosus (L.) M.Bernet & Gray in Gray, Nat. Arr. Brit. Pl. 1: 692. 1821.
Radula nemorosa (L.) Dumort., Commentat. Bot. 112. 1822; Syll. Jungerm. Europ. 41. 1831.
Scapania nemorosa (L.) Dumort., Recueil Observ. Jungerm. 14. 1835.
Plagiochila nemorosa (L.) Mont. & Nees in Nees, Naturgesch. Eur. Leberm. 3: 524. 1838.
Martinellia nemorosa (L.) Lindb., Not. Sällsk. Fauna Fl. Fenn. Förh. 13: 354. 1874.
Type: Europe.
For a complete synonymy see Schuster (1974a).
Plants tinged with pale brown, the stem tips at times tinged purplish, to 4 mm wide, the shoots dorsiventrally flattened. Branching sparingly, the branches lateral-intercalary. Stems deep reddish brown, the cortex in 2–3 layers of very thick-walled, pigmented cells; medullary cells thin-walled, with small corner thickenings. Rhizoids abundant, scattered, in a narrow strip on ventral side of stem and forming a dense, narrow, ridge-like mat. Leaves loosely imbricate, the keel (0.15)0.25–0.35 the ventral lobe in length, without a wing or the wing a short, irregular strip of only a few cells wide, the wing not running the length of the keel, the keel weakly but distinctly arched, the keel-stem angle ca. 60–90°. Ventral lobes moderately to rather strongly convex, the ventral margin sometimes rather sharply deflexed, particularly in basal half, the margin in the basal sector oriented stiffly ventrally or even toward the opposing margin, the deflexed sector extending basally to the extremity of the insertion so that the dorsal surface of the ventral lobe is visible in ventral view, the lobes broadly elliptical-subobovate, 1500–2100 µm wide × 2000–2500(2900) µm long, the width 0.65–0.8× the length, not or moderately arching across but not beyond stem, the lobe-stem angle ca. 60–90°; apex broadly and evenly rounded or feebly angled, without or with differentiation of a somewhat more prominent tooth, the more prominent tooth broad-based, with a uniseriate row of to 3 cells and, below, 1–2 pairs of opposing spinose teeth; lobe margins except near bases (of both ventral and dorsal margin) regularly, sharply, rather closely spinose-dentate, the teeth 2–4(5) cells long and 1–2 cells wide at base, the terminal cell rather sharply tapering to the summit, ca. 2.5× longer than wide, the teeth (especially those below) at times consisting of 1 tapering cell; ventral margin rather sharply narrowed toward base, the base narrowed into a gradually attenuated, entire, long-decurrent strip that extends below the level of the keelar insertion. Dorsal lobe with insertion oblique, arcuate, the lobe moderately convex, obliquely reniform-rectangular, the width 0.95–1.4 the length, arching across and considerably beyond stem, rather suddenly narrowed to the oblique base, 0.45–0.55 the ventral in size, widest at or below middle, the apex obtusely pointed to suddenly apiculate with a sharp tooth, the free margin ± toothed in distal ca. 0.5, the basal half entire, the non-free margin armed throughout or the basal half entire, the teeth of dorsal lobe similar to those of ventral lobe, free margin distinctly decurrent at base. Cells of median sector of ventral lobe thin-walled, trigones lacking, 19–25 µm wide × 24–30(36) µm long; marginal cells (median sector of lobe) firm-walled, without trigones, forming a weakly differentiated border 3–4 cells broad, the marginal cells with dilated septa; surface striate-papillose. Gemmae pale brownish, 1-celled, ellipsoidal, 9.6 × 13.4–17.8 µm. Fungal partner absent.
Dioecious. Androecia terminal but becoming intercalary, the bracts with dorsal lobe ± transversely inserted, inflated, the margins subentire or with several teeth distally, the ventral lobe much larger, dentate distally; antheridia 5–6 per bract; paraphyllia numerous among antheridia, rather long, 1–2-seriate. Gynoecia not seen.
Distribution and Ecology : Bipolar, in the Holarctic occurring from 30–55° N, and common in both warm temperate areas and cold boreal forests (cf. Schuster, 1974a for comments on distribution). In the Southern Hemisphere known only from the North Island, northwest Ruahine Limestone Plateau, 1090 m, in seepage in herbfield associated with Fissidens spp., Bryum spp. and other cryptogams (13/11/1983, Bartlett 30091/c [JE!]).
Comments : The New Zealand population compares rather well with Northern Hemisphere populations of Scapania nemorosa. For example, our plants have several characters that define S. nemorosa, namely the distinctly arcuately inserted ventral lobe, with the decurrent strip extending below the level of the keelar insertion (Fig. 171: 2); the oblique, arcuately inserted dorsal lobe, with the free margin distinctly decurrent at the base (Fig. 171: 1); the obliquely reniform-rectangular dorsal lobes, with the apex obtusely pointed to suddenly apiculate (Fig. 171: 4, 5); the sharply spinose-dentate leaf margins, with better-developed teeth 2–4(5) cells long and 1–2 cells wide at base, and with the terminal cell ca. 2.5× longer than wide (Fig. 171: 8); the broadly elliptical-subobovate ventral lobes (Fig. 171: 4, 5); and the 1-celled gemmae (Fig. 171: 10).
The New Zealand population is devoid of leaf cell trigones (Fig. 171: 6), while Northern Hemisphere plants have trigones at least concave-sided and they occasionally may be bulging (Schuster, 1974a). Schuster (1974a, fig. 424: 3, p. 578) illustrates cells with minute trigones.
The description of the species is based entirely on a small specimen from New Zealand very kindly sent to the senior author by the late Riclef Grolle.
We follow use of the specific epithet “ nemorosa ” for reasons outlined in Schuster (1974a, p. 577). Grolle (1964a, p. 160) argued for the use of the epithet “ Scapania nemorea ” (L.) Grolle.
