Adelanthus gemmiparus (R.M.Schust.) E.A.Hodgs.
Calyptrocolea gemmipara R.M.Schust., Rev. Bryol. Lichénol. 34: 695. 1967 (1966).
Holotype: New Zealand, South Is., Westland, 0.6 miles below Haast Pass, ca. 1650–1700 ft., Schuster 53384 (herb. Schuster, non vidi); isotype: (G!).
[Plate 12A; Fig. 131; Fig. 146: 1, oil-bodies, p. 672]
Plants forming ± interwoven mats, the ± rigid leafy shoots erect, sparingly branched, straight and not cernuous, of limited length, arising from a creeping and descending system of leafless, rhizoidous axes, or from basal sectors of eventually leafy stems, olive-green to deep green, nitid, the stems ± brownish but never blackish with age, the plants small, to 1450 µm wide. Branching exclusively ventral- and lateral-intercalary (from ventral angle of lateral leaves), the leafy branches arising at ± right angles to parent axis but soon abruptly geniculate and becoming erect, often with a brownish, vestigially leaved geotropic stolon arising just above the point of origin of the eventually leafy axis. Stems rigid, the cortical cells very thick-walled, in 2(3) strata, in surface view narrowly rectangular, their lumina reduced and rounded in cross section. Leaves rather stiffly and widely patent, distichous, distant, subtransversely oriented, the insertion almost transverse dorsally but succubous elsewhere, inserted to stem midline dorsally, slightly concave at the base, elsewhere nearly flat and somewhat squarrose, equal-sized, symmetrical, almost orbicular to broadly oval or feebly obovate, longer than wide at least in median sector of shoots, the leaves 375–390 µm wide × 400–410 µm long to 725–750 µm wide × 725–815 µm long; margins entire except for the faint crenulations formed by the protuberant radial walls of marginal cells, the marginal cells often forming a weakly elevated border. Cells of lamina ± thin-walled but with moderate to rather conspicuous, concave- or weakly convex-sided trigones, the subapical cells 17–23 µm wide and long, the median cells 15–18 × 16–22 µm; basal cells not forming a distinct field, the cells relatively weakly elongated, 14–20 × 25–45 µm (2–3:1); marginal cells 10–15 µm and subquadrate or a little elongated at right angles to margin, trigones weak, concave-sided, the cells in marginal 3–4 rows forming an indistinct border, the radial walls swollen externally and dilated, the leaves thus feebly crenulate; surface smooth. Oil-bodies occupying a conspicuous part of the cell, greyish at lower magnification, dull opaque very pale grey at higher magnification, (2)3–4(5) per median leaf cell, finely papillose, the spherules protruding beyond the membrane. Chloroplasts large for cell size. Underleaves inconspicuous and easily overlooked, reduced to 2–3 slime papillae subtended by 1 or a pair of laterally juxtaposed, thick-walled cells. Asexual reproduction by 1-celled, pale to greenish, thin-walled gemmae, either from margins of leaves and 10–11 × 12–16 µm, or from apices of geotropic axes and 7.5–9 × 11–16 µm.
Androecia very compact, small, ± hyaline, arising from bases of ventral branches or stolons; bracts strongly concave, imbricate, in 4–6 pairs, unlobed, hyaline or subhyaline, in part margined as in leaves, faintly crenulate, the marginal cells elongated at right angles to margin; antheridia 1 per bract. Gynoecia on short, ventral branches that are initially somewhat spreading but become abruptly arched and erect; bracts and bracteoles in (2)3–4 gyres, those below small, scale-like, enclosing the innermost gyre of bracts and bracteoles; innermost bracts ovate or ovate-pointed, bidentate to shortly bifid or the arched dorsal margin with 2(3) small, erect, ± denticulate lobules, the margins sparingly setulose-ciliate or setulose-denticulate above with variable teeth, in part merely projections of upper ends of cells; bracteole large, with margins like bracts, but lanceolate-pointed, apiculate with 2–3 superposed cells. Shoot-calyptra erect, green, thick-walled, 1150–1300 µm long, bearing on its surface unfertilized archegonia and scattered, irregular few-celled, loosely attached papillae. Perianth lacking.
Capsule (known only immature) with 4–6-stratose wall. Elaters bispiral.
Distribution and Ecology : New Zealand: Stewart Island, South Island (610–1200 m), North Island (760–1320 m); Australia: Rare in Tasmania (Engel, 1991c). Known from Otago, Westland, Canterbury (Arthur’s Pass), Western Nelson, Gisborne and Volcanic Plateau EPs.
This rather small and nondescript species has a sporadic distribution and is usually found in moist, deeply shaded situations often on wet peaty banks or on peat-covered rock. At Bridal Veil Track (Arthur’s Pass, E side of Bealey River, 760–825 m), occurring mixed with Eotrichocolea polyacantha at the base of a pocket of a vertical mossy bank in a forest dominated by Nothofagus solandri var. cliffortioides with some Griselinia littoralis and Pseudopanax. At the Owen River found under Nothofagus fusca forest on a soil bank, with Pyrrhobryum mnioides, Schizymenium bryoides and Tylimanthus diversifolius. Also known from a stream bank at Temple Basin (Arthur’s Pass, 760 m), in Chionochloa pallens tussockland on the Wilberg Ra. (central Westland, 1030 m) and on Mt. Misery (Otago, 610 m). The type occurred 1 km west of Haast Pass. Also known from a few stations in the North Island. At the summit area of Te Rangaakapua (Huiarau Ra., Urewera Natl. Park, 1320 m) forming an extensive pure thick mat on a vertical rock wall in a mossy forest dominated by Nothofagus menziesii with some Olearia colensoi. Also at the margin of Lake Waikareiti (Urewera Natl. Park). Schuster (1967c, p. 697) recorded the species from soil over rock on the slope of Mt. Taranaki, at 1370–1525 m, in the Chionochloa – Hebe transition between alpine tussockland zone and penalpine scrub, on a moist rock wall with Hymenophyllum multifidum. Also growing with Herzogianthus vaginatus over a deep humus layer on a bryophyte-covered cliff face above the Mangawhero River (near Ohakune Mtn. Road, Tongariro Natl. Park) in an open, low Nothofagus solandri var. cliffortioides forest with Libocedrus bidwillii.
Other species that have been found with Adelanthus gemmiparus are A. occlusus, Categonium nitens, Chiloscyphus mittenianus, Jamesoniella colorata, Kurzia hippuroides, Lepidogyna hodgsoniae and Lepidozia obtusiloba.
Comments : In the field, the aspect of the plant is distinctive: the erect leafy shoots rarely exceed 10 mm high, with a tendency to grow as isolated, well-spaced, unbranched axes (the extensive system of ramified leafless axes scarcely evident), and the green to deep green color of the remote, rather stiffly spreading leaves, the stems at most light brown. When the plants are dissected out, the extensive system of geotropic stolons, arising from brownish lower sectors of stems, is evident. Some of these long and slender geotropic axes terminate in 1–2 small, reduced scale-like leaves that enclose an intensely green mass of gemmae.
As in other Adelanthaceae, the intercalary branches, arising either from the ventral angle of lateral leaves, or appearing to be truly ventral, are initially leafless and become abruptly erect prior to initiation of leaves. Just above their origin, such eventually leafy branches almost always form geotropic, leafless axes, the two branches aligned at 180° to each other.
Adelanthus gemmiparus is closely allied to A. tenuis J.J.Engel & Grolle of southernmost South America and the Falkland Islands (see comments in Schuster, 2002a).
Adelanthus gemmiparus may be confused with Hepatostolonophora rotata var. perssonii (R.M.Schust.) J.J.Engel (≡Calyptrocolea perssonii R.M.Schust.), which is similar in size and has similarly oriented, suborbicular, obliquely to widely spreading leaves. This species also develops stoloniform geotropic axes, but these clearly arise in the axils of lateral leaves. In A. gemmiparus the stolons are brownish, at least with age, whereas in H. rotata they are purplish-tinged distally; the former lacks underleaves and has oil-bodies in all leaf cells, the latter has small, appressed underleaves and dimorphic cells, some with, some without oil-bodies. In cases of doubt, the peculiar differentiated leaf margins of A. gemmiparus are diagnostic: the radial walls of the marginal cells have dilated outer edges, so that leaves appear weakly and remotely crenulate.
Since several genera contain Adelanthus gemmiparus “look-alikes,” a careful search for gynoecia or androecia should be made for generic confirmation.
