Lepidozia glaucescens J.J.Engel
Holotype: New Zealand, South Is., Nelson/Westland Prov. boundary, Pororari River Track, 5 km from road, ca. 500 ft., Child H4966 (F); isotype: (CHR).
Plants loosely creeping, or if on vertical banks, then oriented stiffly from substrate, in loosely interwoven mats, the shoots slender, fragile, with widely spreading branches, fragile, brownish and subnitid to glaucous and ivory-white (at least on new growth), the surface then dull and water-repellent, the shoots medium, to 2.5 cm wide, including branches. Branching nearly exclusively of Frullania type, ± regularly 1-pinnate to remotely 2-pinnate, the branches gradually tapering, becoming whip-like, flagelliform and microphyllous; secondary branches sporadic; branch half-leaf narrow, linear, subsymmetrical, subcordate at the base, 2-lobed to ca. 0.4; first branch underleaf mostly undivided, less commonly 2(4)-lobed, inserted on ventral-lateral side of branch base and aligned with underleaves of branch. Ventral-intercalary branching rare, leafy. Stem epidermal cells in surface view rather thick-walled, sometimes with a waxy coating like that of the leaves. Leaves fragile, when dry moderately concave, with the lobes curved ventrally; leaves when moist explanate, with spreading lobes, ± distant to contiguous, with much of stem visible in dorsal view, uniform in size (not in sequential sectors of varying size), narrowly inserted and somewhat longer than wide, 0.3–0.5(0.6) mm long and wide, spreading, the insertion varying from weakly to distinctly incubous; leaves moderately to distinctly asymmetric, unequally 4-lobed, the leaves divided to ca. 0.4–0.55 (median sinus). Lobes narrowly attenuate to acuminate, the dorsal lobes ± paired, the ventral shorter than the dorsal lobes and somewhat divergent, the lobes terminating in a uniseriate row of 3–4(5) cells; cells of uniseriate row isodiametric to ± elongated (to 2:1), thick-walled and often with somewhat swollen septa, the terminal cell often moderately to distinctly elongated, tapering to a point; the dorsal lobe 3–4(5) cells wide at base; surface of lobes striate-papillose, the papillae mostly obscured by the thin and continuous granular coating. Disc moderately to distinctly asymmetric, obliquely truncate and deltoid, 8–12 cells high at dorsal sinus, 5–9 cells high at ventral sinus; dorsal margin ± straight, abruptly cordate at the base, entire; ventral margin entire. Cells of disc-middle thick-walled, with trigones small, the cells somewhat longitudinally elongated, 18–24(28) µm wide × 21–30 µm long, the cells of the narrow dorsal sector smaller and quadrate; median basal cells in 1 (locally 2) rows of enlarged cells; marginal cells of disc and lobes typically with a thickened outer wall (the wall thickening often crescentic and bulging into the cell lumen); surface of disc as in lobes. Underleaves inserted on 4–6 rows of stem cells, spreading, small, ca. 0.9–1× stem width, symmetrically 4-fid to 0.5 (median sinus), the lobes plane, slenderly acuminate, entire, terminating in a uniseriate row of 2–3(5) cells; disc 3–6 cells high at median sinus, the margins plane, entire.
Plants dioecious. Androecia not seen. Gynoecia on abbreviated ventral-intercalary branches issuing from main stem; bracts of innermost series deeply concave, broadly ovate to ± orbicular; apices with 4 short lobes, the apical end of the marginal cells often diverging and forming a slight projection, the lobes thus crenulate; lamina margin bordered by cells of variable shape and orientation, the apical or free end of marginal cells variously divergent and forming a short projection or a tooth, the margin irregularly crenate-denticulate to the base; bracteole similar in size and form. Perianth long and prominent, slenderly cylindrical-fusiform, slightly curved, terete below, obscurely trigonous above, distinctly and deeply 3-plicate toward mouth, the perianth gradually narrowing toward the strongly contracted, shallowly 3-lobed mouth, the lobes composed of rather thick-walled, papillose cells that at the apical end are laterally free for varying lengths, the lobes crenate-denticulate.
Sporophyte not seen.
Distribution and Ecology : Endemic to New Zealand: South Island (120–300 m), North Island (340–840 m), Chatham Islands (240 m). Known from Westland, Western Nelson, Auckland (Coromandel Forest Park, Waitakere Ra.) and Northland EPs.
Apparently primarily a lower-elevation species. In South Westland (Monkey Puzzle Gorge) the species occurred in a very protected niche: over soil deep in a pocket under a mass of fallen trees in a forest dominated by Nothofagus menziesii and Dacrydium cupressinum. At Lake Kaniere Scenic Reserve (Westland) the species occurs at 125 m in a mixed podocarp–broadleaf forest including narrow, shallow and stagnant pools with saturated, rich, peaty soil. At this site the vegetation consists of Dacrydium cupressinum, Weinmannia racemosa, Podocarpus totara, Metrosideros umbellata and an open understory dominated by Pseudowintera colorata, and Lepidozia glaucescens occurred loosely creeping over and among Bazzania novae-zelandiae or Heteroscyphus decipiens on the sides of bryophyte mounds. Also from beside a pool in a pakihi area under Leptospermum scoparium. Also known from a few sites in the North Island. In the Waipoua Forest in a wet forest dominated by Weinmannia silvicola, growing on the top of a bryophyte-covered log, as well as in Agathis australis forest with Dacrydium cupressinum and other podocarps, with an abundant ground tier of Gahnia xanthocarpa, where the species occurred in a shaded, protected niche on the ventral-lateral side of a log. Near the summit area of “Little Moehau” (Coromandel Forest Park, ca. 800–840 m) the species occurred in protected niches on vertical, shaded banks, in an area of rocky outcrops and shrub-heath communities including Dracophyllum recurvum, Lepidothamnus laxifolius, Coprosma foetidissima, Oreobolus pectinatus and Corokia buddleioides. On Chatham Island it occurred on damp rocks and banks in a dense broadleaf forest, and on peaty soil in a clear- ing in Dracophyllum arboreum – Corokia macrocarpa treeland. Species recorded with L. glaucescens are Hypnum chrysogaster, Kurzia hippuroides and Zoopsis argentea.
Comments : Lepidozia glaucescens differs from the other glaucous-leaved species of the genus by having distinctly asymmetric leaves, with a ± straight dorsal margin (Fig. 49: 1, 3, 4, 7). The leaf cells and the cortical cells of the stem (in surface view) are distinctly thick-walled (Fig. 49: 11), rather than leptodermous as in L. bisbifida and L. digitata, and the wall thickenings have a distinctive lamellated (layered) appearance (Fig. 49: 10). The first branch underleaf is typically undivided in both L. glaucescens and L. glaucophylla.
The leaves of Lepidozia glaucescens are remarkable because of the unique combination of cells with discrete elliptical papillae and a ± uniform waxy, granular coating (Fig. 49: 10). The papillae are hemispherical to short on the lobes (Fig. 49: 10), but distinctly elongate in the median and basal sectors of the disc (Fig. 49: 11). The waxy coating is poorly developed in many collections, however, and is often evident only on the new growth at the tips of the shoots. Consequently, L. glaucescens might be mistaken for L. novae-zelandiae, which also has a striate-papillose surface, similar leaf shape, and lobes terminating in a differentiated uniseriate row of elongated, thick-walled cells. Under the compound microscope, however, the leaf surface of L. glaucescens has a semiopaque, granular appearance, even if the waxy coating is not apparent under the dissecting microscope.
Plants with an apparently smooth surface but possessing ± flat discs with spreading lobes, ± straight dorsal margin of the leaf, and thick-walled lobe and disc cells should be determined with great care. Some populations of the species have surface papillae suboptimally developed, and several leaves from various areas of, preferably, several shoots should be examined (including leaves from near the shoot apex). Verification under oil-immersion is at times helpful.
