Hygrolembidium australe (Steph.) Grolle
Hygrobiella australis Steph., Sp. Hepat. 3: 358. 1908.
Metahygrobiella australis (Steph.) R.M.Schust., Bryologist 64: 206. 1961.
Lembidium australe (Steph.) Grolle, J. Hattori Bot. Lab. 26: 4. 1963.
Hygrolembidium australe (Steph.) Grolle, J. Jap. Bot. 41: 229. 1966.
Type: New Zealand, South Is., Arthur’s Pass, Goebel (G!).
Lembidium stereophyllum Herzog, Ark. Bot. N.S. 1: 491. f. 8–9. 1952 (1951).
Hygrolembidium stereophyllum (Herzog) R.M.Schust., J. Hattori Bot. Lab. 26: 277. 1963.
Type: New Zealand, North Is., Tararua Mtns., Mt. Hector, Watercourse W of Kime Hut, ca. 4200 ft., 31 Dec. 1933, Zotov (CHR ex herb. Hodgson no. 39!).
Plants pure, clear green, variable, especially in size, the leafy shoots to 1.5 mm wide. Branching abundant, the leafy branches ventral- or lateral-intercalary and from a system of creeping, freely branched, colorless, long, slender stolons, the leafy branches issuing only from microphyllous sectors of plants and not from leafy sectors of another leafy shoot. Stem cortical cells leptodermous, usually in 19–20 to over 30 rows, the medullary cells very large, pellucid. Rhizoids mostly lacking on erect, leafy shoots, but if present, then from basal cells of underleaf or from stem at immediate base of underleaf. Leaves rather rigid, fleshy, polystratose in median and basal sectors, the peripheral and distal sectors unistratose in an area below apex and within lateral margins; leaves in cross section toward base 3–5-stratose in intramarginal sectors, the marginal sectors remaining polystratose or thinning to unistratose; epidermal cells of leaf moderately smaller in diameter than internal cells; leaves increasing in size upward, or (on longer shoots) remaining ± equal in size except for smaller leaves near the apex, the leaves contiguous to moderately imbricate, suberect to obliquely spreading, ± loosely sheathing stem, feebly to distinctly succubously inserted, deeply concave, at times subcupulate, ovate, widest in basal one third or in the middle and narrowed to the blunt, very concave, undivided, never retuse apex; lamina margins entire. Larger leaves (700)950–1100 µm wide × (1000)1120–1200 µm long (when flattened, which is difficult to do without tearing the leaf). Cells of apical sector ± strongly elongated, narrowly oblong, ± prosenchymatous, thick-walled, (12)15–26 µm wide × (35)40–60(90) µm long; median cells 18–26 µm wide × 34–50(72) µm long; basal cells not or hardly larger; cells of unistratose region firm-walled, those of polystratose area leptodermous, delicate, chlorophyllose; surface of distal and marginal cells papillose (sometimes faintly so), that of median portion of leaf smooth or (rarely) delicately granulate-papillate. Oil-bodies (Schuster and Engel, 1987b) lacking in unistratose portion of leaf, present in all or most cells of polystratose region, there 1–2(3) per cell (some internal cells with 3–9 oil-bodies); oil-bodies small, glistening, 2.5–3.5 × 5 µm to 3.5–5 × 5–6 µm, the smaller sometimes unsegmented, the larger coarse, few-segmented. Underleaves small, often inconspicuous and appearing as if lacking, plane to weakly concave, variable in shape: lingulate to oblong-ovate or wide-ovate to suborbicular, the apex crenulate; lamina margins entire. Fungal partner an ascomycete.
♂ Plants small. Androecial branches originating from axils of underleaves or leaves, sometimes very small and slender, at other times a little less vigorous than smaller vegetative branches; bracts unlobed, of similar form to leaves, the apices and sides suberect; antheridia (1)2–3(4) per bract, the stalk 2–4-seriate. Gynoecia on ± abbreviated ventral- or lateral-intercalary branches; bracts and bracteoles concave, similar or bracteole somewhat smaller, the bracts widely spaced, somewhat larger than leaves, ovate to wide-elliptic, the apex 0.15–0.2(0.4) bilobed and with lobes variable-denticulate above (often with free ends of elongated cells ± sigmoid) or unlobed and blunt to broad-acute, crenulate, the lamina margins entire or with a ciliiform projection. Perianth very large for plant size, to 3 mm long × 1.4 mm in diam., oblong-fusiform or (less often) ovate, cylindrical below and bluntly 3(4)-gonous above, the mouth lobulate-fimbriolate to crenulate-ciliolate with narrow, often strongly elongated cells and short cilia (to 120 µm long); perianth 3–4(5)-stratose in basal and median sectors.
Seta with (14)16–18 rows of large epidermal cells. Capsule ellipsoidal, the wall 3–4(5)-stratose and ca. 35–39 µm when 5-stratose; outer layer of cells with 2–3 to 4–6 nodular thickenings per face of all or almost all longitudinal walls (primary walls sometimes with thickenings weaker and more yellowish, rather than brownish); innermost layer of cells with almost exclusively nodular to weak or imperfect semiannular thickenings.
Spores 13.5–17.5 µm in diam., the wall yellow-brown, papillate-granulate to papillate, the markings partly coalescent and forming short-vermiculate lines, the spores 2× the elater diam. Elaters ± tortuous, bispiral, 6.7–9.5 µm in diam., the spirals 3–3.3 µm wide.
Distribution and Ecology : Endemic to New Zealand: Campbell Island, South Island (1000–1550 m), North Island (840–1800 m). Known from Fiordland, Southland (Blue Mtns.), Otago (Rock and Pillar Ra.), Westland (Spenser Mtns., Mt. Te Kinga, upper Otira River), Western Nelson (Mt. Peel), Sounds–Nelson (Richmond Ra.) and Auckland (Mt. Moehau) EPs.
Widespread but sporadic in distribution. The species occurs primarily in alpine and penalpine, moory sites mostly at 855–1800 m, but sporadically at lower elevations (520–825 m). In the alpine zone it grows along small rills in deep shade under tussock blades where conditions are permanently moist. Also over soil near the edges of tarns and on lips of stagnant pools in mosaics of tussock grass and alpine vegetation along with tarns, pools, rills, rocky outcrops and boulderfields. In these sites it grows with Sphagnum cristatum, S. falcatulum (growing at times on the surface of the Sphagnum), Campylopus clavatus, C. introflexus, Kurzia hippuroides and K. calcarata, Pachyglossa tenacifolia, Pseudocephalozia paludicola and Siphula rubra. The species also may be found in more exposed situations; for example, it occurs over bare soil of exposed portions of slopes as well as over soil of pockets on ice-scoured slopes. In penalpine communities the species occurs over soil in vegetation dominated by Chionochloa (but with some scattered Dracophyllum and Phormium cookianum) as well as near rills or under tussock overhangs in scrub consisting mainly of Chionochloa, Dracophyllum and Hebe. In these sites it occurs with Cladia aggregata, Conostomum pusillum, Ditrichum difficile, D. punctulatum, Notoligotrichum australe, Philonotis tenuis and Racomitrium lanuginosum. At somewhat lower elevations over soil of vertical banks of drainage channels; e.g., on Mt. Moehau (Coromandel Forest Park, ca. 840 m) it occurred in a narrow truncated valley system under stunted Weinmannia silvicola, Coprosma foetidissima and Corokia buddleioides. The species rarely occurs in Nothofagus forests; e.g., near the South Branch of Borland Burn (Fiordland, 855–870 m) the species occurs over peaty soil at the side of a normally dry stream channel.
Comments : Vegetatively this species, like other Hygrolembidium species, is extremely variable, especially in size. Plants often are dwarfed and bear smaller, often shorter, less concave leaves, never folded at the tips; they seem always to be rather remote-leaved.
All forms of Hygrolembidium australe are at once distinct from H. rigidum, which may occur admixed with this species, in the 1) bluntly pointed to ± rounded leaves whose apices are never incised or retuse; 2) much smaller underleaves; and 3) firm-walled leaf cells (except at the leaf bases), strongly elongated and (marginally) prosenchymatous in form. Also, oil-bodies are present at least in some cells; in H. rigidum no cells ever bear oil-bodies.
