Wettsteinia schusteriana Grolle
Wettsteinia schusteriana Grolle, J. Hattori Bot. Lab. 28: 99. f. 2. 1965.
Adelanthus schusterianus (Grolle) E.A.Hodgs., Trans. Roy. Soc. New Zealand, Bot. 3: 176. 1967.
Holotype: New Zealand, South Is., Fiordland Natl. Park, Cascade Creek, J. Burrell, G. A. M. Scott & J. Taylor (CHR 135094!); isotype: (CHR ex herb. Allison H6526!).
Plants light green, the lower parts of stems whitish, the erect shoots typically leafless below, gradually larger-leaved above, the distal sector of shoot cernuous, with the leaves smaller and more densely imbricate, the plants vigorous, to 7 cm tall. Plants with a strongly developed system of basal, creeping, plagiotropic, often whitish stolons, from which arise erect, typically unbranched shoots; stolons and leafless sectors of erect axes giving rise to intercalary, geotropic, microphyllous, root-like axes, and also to intercalary, considerably more slender and whip-like secondary branches (“secondary roots”). Branching ventral-intercalary, arising from the stolons and lower sectors of leafy shoots. Stems comprised of a hyaloderm of 1–2 layers of numerous thin-walled, relatively small cells that collapse with age and 3–5 subepidermal strata of smaller, thick-walled cells that gradually grade into the large, hyaline, weakly firm-walled medullary cells. Rhizoids absent on leafy shoots. Leaves (optimally developed, in median sector of shoot) rather stiff and firmly attached to stem, ± clasping the stem, 2–4-stratose toward base, widely spreading but becoming inclined toward the stem and laterally appressed with opposing leaves, approximate to loosely imbricate, the insertion markedly narrow, the leaves distinctly concave, especially in dorsal, basal sector (the dorsal margin inflexed at least in the basal sector), somewhat asymmetrically orbicular to very broadly ovate to subreniform, 4200–4800 µm wide × 3600–4500 µm long, as wide as or wider than long, the dorsal and ventral bases ampliate, the ventral somewhat more strongly so and often subauriculate; margins copiously and finely dentate, the dorsal with teeth larger and more remote, the apex and ventral margin with smaller, somewhat irregular teeth. Leaves in distal sector of shoot smaller, becoming obovate. Cells in median sector of leaf with walls firm, with trigones straight-sided to weakly bulging, 22–30 µm wide × 30–40 µm long; basal cells only moderately elongated, to 50(60) µm long; marginal and intramarginal cells thick-walled. Oil-bodies hyaline, 10–18 per cell in median sector of leaf, finely papillose, the spherules very slightly protruding beyond outer membrane, the oil-bodies globose and 4.8–6.2 µm in diam. to ovoid to broadly elliptic and 4.3–5.8 × 6.7–9.1 µm, less often narrowly elliptic and 4.3 × 8.2 µm, often irregular in shape. Underleaves vestigial, in leafy sectors of shoot, especially distally, ciliiform on upper shoot sectors. Asexual reproduction absent. Fungal partner absent.
Plants dioecious. Androecia not seen. Gynoecia on strongly abbreviated intercalary branches from extreme basal, leafless sectors of upright leafy shoots; bracts and bracteoles small, bleached, irregularly laciniate, comprised of thin-walled hyaline cells. Perianth absent. Shoot-calyptra rigid, fleshy, stoutly clavate, whitish at time of capsule dehiscence, long-exserted beyond bracts, the sterile archegonia elevated on the shoot-calyptra and scattered throughout (even near the summit), the bractlets at times elevated on the shoot-calyptra, but at the time of capsule dehiscence the bractlets inconspicuous, scale-like, leptodermous, the margins irregularly crenulate-denticulate with 1-celled teeth or the bractlets falling away and the calyptra then appearing to lack them.
Seta massive, appearing ribbed (?always), with ca. 85 rows of outer rows surrounding numerous internal cells that are ± similar or a little larger. Capsule moderately long-ellipsoidal, the wall 6–8-stratose, 90–94 µm thick, the outer layer of cells equal to thickness of 2.2–3 of interior strata; outer layer of cells very small, of irregular shape, for the most part irregularly subrectangular, the walls very thin, mostly devoid of thickenings but some cells with longitudinal walls with nodular to spur-like thickenings, the cells that possess thickenings sporadic in distribution, occasionally clustered, but without a regular pattern of distribution, the transverse walls sporadically with a weak nodular swelling, the outer layer of cells near and at the capsule apex with thickenings on most walls; innermost layer of cells elongate-rectangular, the longitudinal walls with somewhat thick continuous sheets of wall material, semiannular bands on inner walls typically complete, sporadically forked.
Spores yellow-brown, 14.4–16.3 µm in diam., with low but sharply defined close papillae and very short-vermiculate markings. Elaters rather straight to somewhat tortuous, 8.6–9.6 µm wide, somewhat tapered to tips, bispiral to tips, the spirals 2.9–3.4 µm wide.
Distribution and Ecology : Endemic to New Zealand: South Island (100–900 m). Known only from the eastern side of Fiordland (Lake Hauroko and Cascade Creek), Westland (all records from Aspiring ER), Canterbury (Upper Bealey Valley) and Western Nelson (Moonlight Creek) EPs.
Apparently confined to Nothofagus menziesii and mature N. fusca and mixed N. fusca – N. menziesii forests. It may form large, loose, light green tufts on permanently moist, deeply shaded forest ground/humus or on bryophyte-covered logs or in vertical banks of bryophytes. At Moonlight Creek it occurs on a large N. menziesii trunk at a height of about 1 m. It occurs most often with Lepidozia pendulina, but also with Bazzania adnexa, Distichophyllum crispulum, Plagiochila gigantea, Ptychomnion aciculare, Pyrrhobryum mnioides and Tylimanthus saccatus.
Comments : This is a notable plant, distinctive by plant size, with shoots to 7 cm tall and with a strongly developed system of erect, typically unbranched leafy shoots that arise from basal, creeping, plagiotropic stolons. The erect shoots are leafless below, then gradually become larger-leaved above, but the distal sector, which is cernuous, has leaves smaller and more densely imbricate (Fig. 135: 1). The best-developed leaves on the erect shoots are in the median sector and are distinctly concave, orbicular to broadly ovate to subreniform, with the dorsal and ventral bases ampliate (Fig. 135: 2–5). The apex and margins have numerous small teeth (Fig. 135: 3–5, 7). In these respects plants are comparable to Adelanthus, especially A. falcatus. Plants of Wettsteinia schusteriana may be immediately distinguished, however, by the vigorous plant size and the absence of secondary pigments. The leaves of the smaller A. falcatus are green but stems become dark pigmented, often blackish. Also, the median leaf cells of W. schusteriana have small to bulging trigones and 10–18 oil-bodies per cell vs. no trigones and 4–7(10) oil-bodies per cell in A. falcatus. Moreover, Wettsteinia has a collapsing hyaloderm (Fig. 135: 9), which is lacking in all species of Adelanthus.
Plants of Wettsteinia may be confused in the field with Tylimanthus saccatus, which is of similar stature, is comprised of erect, typically unbranched shoots and occurs in similar habitats. Gametangial position (and type of gynoecium) will immediately distinguish these genera, but if only sterile plants are at hand. Wettsteinia has leaves that are very broadly ovate to subreniform and as wide as or wider than long vs. oblong in T. saccatus; leaf margins are finely dentate in Wettsteinia vs. more coarsely so in T. saccatus; and the stem surface is roughened in Wettsteinia vs. smooth in T. saccatus. The roughened, uneven stem surface may be seen even under the dissecting microscope, and countless air bubbles usually may be seen on the surface, likely due to the numerous partially collapsed hyaloderm cells. Also, the erect shoots in Wettsteinia are characteristically bent at ca. 90° about 10 mm from the apex, and the leaves become smaller toward the shoot apex (Plate 12F, Fig. 135: 1), characteristics not shared by T. saccatus.
