Paracromastigum fiordlandiae R.M.Schust. & J.J.Engel
Paracromastigum fiordlandiae R.M.Schust. & J.J.Engel, Brittonia 48: 167. f. 1. 1996.
Holotype: New Zealand, South Is., Fiordland Natl. Park, Mt. Burns, Hunter Mtns., 4500–5000 ft., 9 Jan. 1984, Schuster 84-136 (herb. Schuster).
Plants subisophyllous, soft-textured, fleshy, consisting of interwoven, pale, whitish green, distally brownish or purplish brown pigmented (androecia often more deeply pigmented); shoots thread-like, indefinite in length, ca. 235–285 µm wide with leaves (shoot apices rarely to 325–360 µm wide). Branching copious, nearly exclusively intercalary (85% lateral; 15% ventral); terminal branching very rare (one Acromastigum -type branch seen). Stems fleshy, the cortex in sporadically 8 but mostly 9, occasionally ranging to 12, rows, feebly thick-walled, slightly inflated but much larger than the medullary cells and forming a hyaloderm, in surface view subquadrate to short-rectangular, usually under 2× as long as wide; medullary cells in (11)15–24 rows, the peripheral row somewhat thick-walled but toward the center rather thin-walled. Rhizoids rather rare, mostly at bases of highly reduced underleaves low on the stem, usually 1 or 2 per underleaf base, sporadically from basal cells of underleaves of normal leafy shoots. Main shoots with 6–8 cortical cells intervening between successive leaves on either side. Leaves exceedingly remote, small, their width usually not or barely exceeding stem width but some shoots toward apices with leaves appreciably longer, remaining remote, the insertion (as seen in dorsal aspect) feebly incubous to transverse, extended to stem midline (to the median-longitudinal cell walls), ventrally somewhat obliquely incubous. Mature leaves concave, suberect, hand-like, the lobes erect or more often a little incurved, the leaves when flattened somewhat asymmetrically quadrate-ovate to quadrate-obovate, 400 µm wide × 450 µm long (in the dorsal half, the ventral sector ca. 340 µm long) to 370 µm wide × 540 µm long (then ventrally 500–510 µm long), usually asymmetrically bifid or (less often) trifid for 0.35–0.45 their length; lobes acute (but not long-acute), unequal, the dorsal lobe larger, up to 5–9 cells wide at base, usually terminating in a uniseriate row of 2 cells; ventral 1 or 2 lobes usually a little shorter, few-celled, 4–5 cells broad, blunt at the tips or ending in a single cell and terminating in a slime papilla; leaves exceptionally symmetrically trifid and without reduction of ventral lobe(s); disc 10–21 cells broad, the dorsal margin gently curved, the ventral equally or less so. Cells similar in size throughout leaf, with walls thin in lower half of leaves, a little thickened in the (often pigmented) lobes, devoid of trigones; lobe cells variable in shape and size; median cells very variable, quadrate and 38–42 µm to more often rectangulate and 19–30(36) µm wide × 52–76 µm long; basal cells oblong-hexagonal, 27–32 µm wide × 40–83 µm long; surface smooth or almost so in proximal half of leaf, in lobes finely but distinctly papillose. Oil-bodies lacking. Underleaves large, little or not wider than stem, about 0.55–0.65× area of lateral leaves, usually 15–18 cells broad (but often much smaller), broadly and transversely quadrate-reniform or rounded-oblong, 3–4-lobed to ca. 0.25–0.35; lobes few-celled (usually of 7–9, up to 16–20 cells), usually 1 or 2 lobes a little smaller, but not or weakly asymmetric, the lobes mostly terminating in 2 laterally juxtaposed cells, usually not ending in slime papillae. Asexual reproduction lacking.
Dioecious. Androecia on long or short, leafy branches, terminal but becoming intercalary, wider than vegetative axes (365–380 µm wide), very laxly spicate, usually more deeply pigmented than vegetative area; bracts in 2–6 pairs, remote, similar in size to leaves or barely larger, 2(3)-lobed, with erect to erect-incurved, acute lobes, from a suberect to obliquely spreading, strikingly concave, entire-margined base, the base semicircular in cross section; antheridia 1–2 per bract, nearly occupying the entire bract cavity, the stalk short, biseriate, the body spherical, formed of many irregular jacket-cells of small size; bracteoles distinct, clearly smaller than bracts, lingulate-ovate, a little concave, shallowly bifid, the short lobes usually incurved, lacking antheridia or (sometimes) monandrous. Gynoecia terminal on elongated but small-leaved axes or, more often, on rather abbreviated intercalary branches, arising (sometimes in juxtaposed groups of 3–4) indiscriminately in axils of lateral leaves and underleaves; bracts of innermost series 0.2–0.3(0.35) bifid, elliptical, the lobes acute, sometimes asymmetric, usually terminating in a single, tapered cell, the lobe margins entire; bracteole similar in shape and form, but a little smaller. Perianth fusiform, terete below, plicate in ca. distal half, narrowing to the contracted mouth, the mouth lobulate, the lobules each terminating in a single cell or a uniseriate row of 2 somewhat elongated, rather thin-walled cells, the terminal cell rounded at the summit and not sharp.
Capsule wall outer layer of cells with two-phase development, the longitudinal walls with obscure continuous sheets of secondary wall material and nodular to weakly extended thickenings, alternating with primary walls with thickenings absent or weakly developed.
Spores and elaters not seen.
Distribution and Ecology : Endemic to New Zealand: South Island (1370–1525 m), North Island (1240–1660 m).
A penalpine–alpine plant. In the alpine zone in mosaics of cliffs, outcrops and scattered alpine plants. In such situations it occurs over soil within crevices of boulders, outcrops and cliff faces, particularly where there are pockets or niches offering some degree of protection. It may be admixed with Isotachis or Herzogobryum. At times over soil between boulders in a streambed (Tongariro Natl. Park, Blyth Hut to Whakapapa Track, 1450 m). Also over soil between rocks at a creek margin in an exposed stream valley through penalpine scrub of Halocarpus bidwillii, Ozothamnus leptophyllus and Phyllocladus alpinus (Tongariro Natl. Park, Taranaki Falls Track, 1240 m). The type occurred admixed with Hyalolepidozia over peaty ground in the snow tussock (Chionochloa) zone.
Comments : This species is of particular interest since it possesses in varying degrees features usually regarded as diagnostic of Hyalolepidozia (normally only intercalary branching, both lateral and ventral), of Paracromastigum (the 2–3-lobed leaves and underleaves, the latter quite large, often approaching the leaves in size) and of Pseudocephalozia (the largest leaves and underleaves are relatively many-celled, the leaves 3-lobed on the most vigorous axes, the underleaves are often 4-lobed and the branching is intercalary from all 3 merophyte rows).
With substitution of intercalary for terminal, lateral branching, this species and Paracromastigum drucei are similar in branching modality to Hyalolepidozia. Also, in P. fiordlandiae the stem, with 8 large, inflated cortical cells, has an anatomy that approaches that of Hyalolepidozia (here cortical cells are in only 6 rows).
Paracromastigum fiordlandiae has an affinity to P. drucei in size and aspect, branching modes, leaf lobing and in the exceedingly remote leaves and underleaves. For differences between these species see the key.
The type of Paracromastigum fiordlandiae was described in Schuster and Engel (1996) as lacking perianths, and the small portion sent to Engel for study also lacked perianths. However, Schuster (2000a) illustrated both details of the gynoecium and sporophyte and the above description of these structures is based upon these figures.
