Flora of New Zealand Series

[Plate 15A; Fig. 167; Fig. 169: 1, oil-bodies, p. 766]

Plants creeping, often closely adnate to substrate, the tips ascending, the plants green to whitish green, deeply reddish orange with exposure; shoots small, to 1.4(1.6) mm wide. Branches occasional to frequent, lateral-intercalary. Rhizoids rather dense, mostly from ventral face of stem, occasionally from near base of ventral lobe. Leaves contiguous to imbricate, conduplicate-bilobed, the dorsal lobe slightly elevated or ( var. icari) distinctly elevated and squarrose-recurved, the leaves somewhat dorsally assurgent when dry, when moist horizontal, or ( var. icari) rather strongly dorsally assurgent and then with the shoot appearing concave and channeled in dorsal view, the leaves widely spreading to squarrose, often weakly falcate, the keel 0.25–0.3 the leaf length (0.35–0.5 in var. icari), arched, the cells forming the keel with exceptionally thick walls and an often reduced lumen, the sinus abruptly reflexed and the ventral lobe often flaring just distal to the keel, the opposing dorsal lobes (when leaves imbricate) slightly overlapping, extending to 0.5 the stem width or a little more. Ventral lobe plane or the apex broadly decurved, the insertion ± transverse, the free margin not decurrent, the lobe narrowly oblong-elliptic; apex broadly acute to bluntly rounded, denticulate, typically with a distinct, sharp apiculus composed of 1 to several cells and at most terminating in a uniseriate row of 2 cells; ventral margin broadly and ± symmetrically arched, sharply denticulate to irregularly serrulate to the base, the teeth at the immediate base of margin larger, crowded and sinuous; dorsal margin often somewhat less strongly armed to subentire. Dorsal lobe plane, asymmetrically ovate to elliptic, 0.5–0.7 the length of ventral lobe (0.75–0.85 in var. icari), 0.3–0.45× the area of ventral lobe (0.5–0.7× in var. icari), the insertion ± transverse, not decurrent; apex often reflexed, acute (rarely ± rounded), with a distinct apiculus similar to that of ventral lobe; dorsal (free) margin broadly arched, the margins with denticulation similar to the ventral lobe or more pronounced, the free dorsal margin armed to the base, the teeth in basal portion larger and resembling those of ventral lobe base. Marginal teeth variable in size, unicellular, sharply (and often obliquely) projecting, or consisting of narrower conical projections from the exposed wall of the marginal cells, the margins near the lobe bases more sharply toothed. Cells of median portion of ventral lobe short-rectangular, 10–16 µm wide × 19–29 µm long (ca. 2:1 or more); subapical and marginal cells in ± regular arching tiers, ± isodiametric, subquadrate, uniformly thick-walled, 8–10 µm wide × 10–13 µm long, in a more densely areolate broad marginal band, the median field of elongate cells often extending into the distal sector of the lobe, the lobe thus subvittate; median cells in sheathing portion of leaf short-rectangular, 16–18 µm wide × 30–39 µm long, thin or moderately thick-walled, or ( var. icari) typically narrowly elongate (to 5:1), the longitudinal wall often sinuous-thickened; surface very coarsely papillose, the papillae rounded to elliptic, (1)2–3(4) per cell in distal and marginal cells (sometimes as large as cell lumen); elongate cells of median base finely striolate-papillose. Oil-bodies (see under varieties). Gemmae 1-celled, 11.5–12.5 µm in diam. (including papillae), pale green, polygonal, with thick-walled, tapering protuberances rounded at the summit. Fungal partner a basidiomycete.

Paroecious, the fertile shoots larger. Androecia with (2)3–4 pairs of bracts, the ♂ bracts immediately below the ♀, the dorsal lobes occasionally squarrose, similar to leaves in shape and form except somewhat ventricose toward base; antheridia 1–4 per bract, the stalk uniseriate. Gynoecial bracts somewhat larger than leaves, those of innermost series similar to leaves except the dorsal lobe larger and ca. 0.5 the ventral in size and with the apex rounded and non-apiculate. Perianth typically present, short-elliptic to elliptic-clavate, contracted to mouth, shallowly plurilobulate, the lobule tip rigid, spine-like and terminating in a uniseriate row of 1–2(3) cells, the lobule margins with several sharply angular, mostly 1-celled teeth; gynoecia occasionally with 2 sporophytes.

Capsule ellipsoidal, the wall 3-stratose (exceptionally and then only locally bistratose), 20–26 µm thick, the outer layer of cells equal in thickness to 1.3–1.5 of interior strata; outer layer of cells subquadrate to short-rectangular, without evident two-phase development, the longitudinal walls with nodular to weakly spur-like thickenings, the transverse walls without or with fewer and often smaller thickenings; exposed tangential wall in surface view with an irregular loose reticulum of obscure hyaline wavy ridges that largely obliterates detail of nodular thickenings of outer layer; innermost layer of cells elongate-rectangular, the radial longitudinal walls with nodular to (more often) spur-like thickenings, occasionally tangentially extended into semiannular bands, the bands rather thick for cell size, not forked.

Spores 9.6–10.1 µm in diam., with low but sharply defined papillose and short-vermiculate markings. Elaters tortuous, 6.2–7.2 µm wide, bispiral.

Distribution and Ecology : New Zealand: Campbell Island, South Island ([75]455–1900 m), North Island (170–1700 m); Australia: Tasmania (960–1490 m), Victoria (1450 m), New South Wales (1780–2140 m). In New Zealand known from Fiordland, Southland (Garvie Mtns.), Otago, Westland, Canterbury (including Banks Peninsula), Marlborough, Sounds–Nelson, Western Nelson, Southern North Island (Akatarawa) and Volcanic Plateau EPs.

The species typically occurs on soil within niches associated with boulders or rocky outcrops and here often is present in crevices or deep in moist, shaded, protected pockets or recesses, as well as over soil under ledges. It is relatively common in the penalpine and alpine zones, and in alpine sites occurs in both fellfields and in tussockland. At the higher elevations it primarily occurs in rock crevice niches but also may be found almost as a pioneer over soil of creek banks and exposed, ice-eroded slopes (1250–1450 m on Mt. Armstrong). The species may occur in forest (but primarily above ca. 750 m) dominated by Nothofagus menziesii, N. solandri var. cliffortioides, N. fusca, Dacrydium cupressinum and Weinmannia racemosa, accompanied by Telaranea tuberifera and T. tetrapila. It also occurs on the Volcanic Plateau in the Leptospermum scoparium – Dracophyllum subulatum scrub ecotone (near the eastern border of Tongariro Natl. Park, 750 m), or in the South Island mountains on soil banks in penalpine shrublands of Dracophyllum longifolium, D. rosmarinifolium, Podocarpus nivalis, Ozothamnus leptophyllus, Hebe odora, H. subalpina, Chionochloa flavescens, C. pallens and Schoenus pauciflorus. In such penalpine sites it is associated with Bartramia papillata, Ditrichum punctulatum, Hygrolembidium acrocladum, Notoligotrichum australe, Pohlia wahlenbergii, Racomitrium crispulum, Solenostoma inundatum and S. rufiflorum. In New Zealand the species occurs primarily above 700 m, but may be present at lower elevations in southern sectors of South Island. For example, in South Westland along Cascade Road in the Martyr Saddle area, the species occurs under partial Blechnum cover on vertical roadside banks at only 75–110 m, similarly in the Buller River gorge in Western Nelson. The var. domesticum tends to occur at lower elevations, but may be found in protected niches in the alpine zone, and the var. icari is particularly common in exposed, penalpine–alpine sites.

Comments : Diplophyllum domesticum is a common and highly variable species. The lobe apices are typically broadly but sharply acute, with a small but distinct apiculus (Fig. 167: 2, 3), but are at times bluntly rounded and lack an apiculus. Dentition at the apex varies from coarsely and somewhat irregularly serrulate to regularly and finely denticulate. Color ranges from whitish green to an intense reddish orange. Dorsal lobe orientation varies from plane in shade forms to distinctly squarrose-reflexed in exposed situations. Diplophyllum novum also has subvittate leaves, with an ill-defined field of rectangular cells extending from the base into the distal part of leaf, but the leaves of D. novum are often obliquely inserted in the ventral half vs. ± transversely inserted in D. domesticum.

Diplophyllum domesticum almost always bears gametangia (and often sporophytes), so that the paroecious condition is usually evident. Even when antheridia are no longer present, there are at least a few pairs of leaves below the gynoecium with distinctly ventricose bases. Unlike D. novum, D. domesticum appears to be consistently paroecious; D. novum is sometimes observed to produce androecia on lateral-intercalary branches some distance below gynoecia, whereas D. domesticum typically forms subfloral innovations that terminate in paroecious inflorescences. Diplophyllum verrucosum is also consistently paroecious, but may be readily distinguished by the subequally lobed leaves (Fig. 164: 1–5) with a distinct vitta of narrowly elongate cells (Fig. 164: 5, 10). Diplophyllum dioicum apparently produces gametangia only infrequently, but even when sterile can be distinguished from D. domesticum by the more distinct vitta, which is mostly confined to the keelar region, and the absence of reddish pigmentation, even in exposed situations.

The species has two varieties, as follows.