Solenostoma cryptogynum R.M.Schust.
Solenostoma cryptogynum R.M.Schust. ex J.J.Engel, Novon 17: 311. 2007.
Holotype: New Zealand, North Is., South Auckland Prov., Whirinaki Forest Park, road to Arahaki Lagoon, SSW of Minginui, 380 m, Engel 20730 (F); isotype: (CHR).
[Plate 13B; Fig. 151: 3, 4, oil-bodies, p. 696]
Plants spongy, prostrate to a little ascending, markedly brittle, resembling Solenostoma orbiculatum in general aspect, tightly adhering by abundant rhizoids to other shoots both laterally and below and often forming compact, tight, pure, small mats, the shoots often appearing turgid, the shoots pure green or with stems and leaf bases light green and distal parts of leaves and perianths rusty red, the plants medium-sized, to 3 mm wide. Branching (vegetative) not seen. Stem with cortical cells moderately differentiated, in a single (locally 2) layer of smaller, thin-walled cells; medullary cells thin-walled. Rhizoids numerous, long for shoot size, colorless to pale brownish, diffuse, never in bundles, arising in a rather broad zone from the ventral side of stem and from extreme bases of leaves. Leaves rather rigid, firmly attached, semivertical, obliquely to widely spreading, those toward shoot apices tend to be suberect and shoot tips may be almost bivalved, densely imbricate, subtransversely oriented, the insertion oblique in ca. dorsal two thirds, becoming subtransverse in ventral third; leaves 2-stratose at extreme base in median sector, concave, subsymmetric, suborbicular to oblate to subreniform, often broader than long, entire, (1.7)2–3.2 mm wide, (1.5)1.8–2.8 mm long, the apex broadly rounded; dorsal margin plane, the ventral often sharply reflexed toward base, the dorsal and ventral margins not decurrent. Cells thin-walled, with bulging, nodular trigones; cells of median sector of leaf not much longer than wide, 46–61 µm wide × 50–72 µm long, the cells in distal sector smaller, isodiametric, 35–46 µm wide and long; surface closely striolate-papillose (at least in median and basal sectors). Oil-bodies occupying small to moderate portion of cell, pale brownish or light chocolate-brown, (3)4–6(8) per median leaf cell, coarsely granular, broadly to long-elliptic to fusiform to subcrescentic to linear to paramecioid to potato-shaped, and less often short-elliptic, 9 × 11 µm to 8 × 17 µm to 7–9 × 24–30 µm. Underleaves absent, the ventral merophytes very narrow. Asexual reproduction absent.
Dioecious. Androecia terminal, inconspicuous; bracts hardly differentiated from the leaves, in 4–5 pairs, the margins plane to feebly recurved, the basal portion moderately concave; antheridia 4–5 per bract, the stalk biseriate. Gynoecia terminal, often with an innovation, the innovations ventral-intercalary, the subinvolucral leaves gradually larger, the bracts of innermost series reniform, the bracts in young gynoecia suberect and ± clasping the young perianth; bracteole absent. Perianth when young laterally compressed, with distinct dorsal and ventral keels, the mature perianths included with bracts or extending at most a little beyond, inflated, clavate, ± irregularly and sharply 5-plicate in distal ca. 0.5, the summit of each plica a ± sloping or truncate “shoulder,” the mouth contracted to a distinct beak, the beak summit crenulate by cells that are somewhat elongate, uniformly thick-walled, and with their tips somewhat irregularly projecting, with sporophyte extrusion the beaked perianth apex becomes strongly fissured, the beak splitting into several tapered segments.
Seta seen only in collapsed state. Capsule irregularly splitting into ca. 6 valves, the wall carmine red, 3(locally 4)-stratose, 52–56 µm thick, the outer layer ca. 0.6 the total wall thickness; outer layer of cells subquadrate to short-rectangular, thin-walled, with prominent deep carmine to almost blackish nodule-like thickenings on most longitudinal walls and absent or few on transverse walls; inner layer of irregularly elongated cells, the longitudinal walls with very thin, evenly sheet-like, pigmented thickenings and narrow, usually complete semiannular bands, the bands not branched.
Spores pale red-brown, 15.8–18.2 µm in diam., with low, delicate, well-defined short-vermiculate markings that often branch and coalesce, the surface also with a few papillae. Elaters tortuous, 9.1 µm wide, bispiral, the ends thick-walled and nonspiral, the thick-walled portion ± parallel-sided, the spirals 3.8–4.8 µm wide.
Distribution and Ecology : Endemic to New Zealand: South Island (100–500 m), North Island (380 m). Known only from Westland and Volcanic Plateau EPs, from a few collections, but likely will be found to be more common after study of specimens previously thought to be Solenostoma orbiculatum. At Whirinaki Forest Park, road to Arahaki Lagoon (Volcanic Plateau EP), plants occurred on soil over rock in thick Leptospermum scoparium scrub. In Westland, it has been found on the vertical edges of outwash and moraine terraces, on coarsely stony soils, under Dacrydium cupressinum – Weinmannia racemosa forest or Nothofagus fusca forest, or in the open adjacent to a river. It has been found at these sites with Campylopus clavatus, C. spiniferus, Dibaeis arcuata, Isotachis lyallii, Nertera balfouriana and Pallavicinia xiphoides.
Comments : The species is similar to Solenostoma orbiculatum in general appearance and, as mentioned above, specimens have probably been misdetermined as that species. The gynoecium of S. cryptogynum is quite different in that the perianths, when young, are laterally compressed and at maturity are included within the bracts vs. perianths that when young are inflated and not laterally compressed, and at maturity are long-exserted beyond the bracts in S. orbiculatum. When sterile, plants of the two species may be distinguished by several characters. In S. cryptogynum the leaves are subtransversely oriented, with non-decurrent dorsal and ventral margins, and the median cells are 46–61 µm wide × 50–72 µm long vs. leaves that are succubously oriented, with the dorsal and ventral margins short-decurrent, and median cells (27)30–43(48) µm wide × 41–48(55) µm long in S. orbiculatum.
Plants of this species, like Solenostoma hodgsoniae and probably some of our other species, have a notable habit. Shoots tightly adhere by abundant rhizoids to other shoots in the same populations, both to living shoots that are ± lateral as well as to colorless, probably nonliving ones below. These colorless shoots, in turn, similarly adhere to other shoots laterally and below, the entire mass forming a tight, compact, thick, rather solid mat.
