Paracromastigum macrostipum (Steph.) R.M.Schust.
Cephalozia macrostipa Steph., Hedwigia 32: 315. 1893.
Paracromastigum macrostipum (Steph.) R.M.Schust., J. Hattori Bot. Lab. 26: 276. 1963.
Pseudocephalozia macrostipa (Steph.) R.M.Schust., Nova Hedwigia 10: 21. 1965.
Type: New Zealand, Tauranga, Kirk 113 – c. per. (G!).
Cephalozia kirkii Steph., Sp. Hepat. 3: 314. 1908, syn. fide Schuster (2000a, p. 374).
Paracromastigum kirkii (Steph.) R.M.Schust., J. Hattori Bot. Lab. 26: 276. 1963.
Type: New Zealand, Tauranga, Kirk 407– c. sporo. (G!)
Plants creeping to ascending, green in shade phases, with exposure developing reddish brown pigments, 310–600 µm wide, the basal portion often creeping, whitish, microphyllous and flagelliform prior to becoming leafy, the leading leafy shoots often broadly arching. Branching common, the branches ascending, frequently of Acromastigum type, occasionally of Frullania type; Microlepidozia -type branches lacking; ventral-intercalary branches abundant. Stems with cortex firm-walled, much larger than the thin- to weakly firm-walled medullary cells, the stems with 10–11 rows of cortical cells + 8–10 rows of medullary cells varying to 6–7 cortical cells + 5–6 medullary cells. Rhizoids at underleaf bases. Main shoots with 2–3 elongate-rectangular cortical cells intervening between successive leaves on either side. Leaves vertical, rather strongly dorsally assurgent, suberect, imbricate, the insertion succubous (at times feebly so), not inserted to stem midline dorsally, at least part of the dorsal 2 cell rows leaf-free, the leaves 300–360 µm wide × 400–480 µm long, bifid or (frequently) trifid, the leaves divided to ca. 0.45–0.55; lobes acute, 4–6 cells wide at base, terminating in a single isodiametric cell or a uniseriate row of 2 subisodiametric cells, the tip cell rather broadly rounded at the summit; disc 2–4 cells high, the basal tier tending to be larger, or at least longer, the disc 10–14 cells wide. Cells feebly, equally firm-walled, the median disc cells 22–30 µm wide × 37–54(60) µm long; surface weakly striate-papillose. Oil-bodies present in some cells, especially toward the base of the disc, occupying a tiny fraction of the cell, hyaline, glistening, 2–3 per basal disc cell, conspicuously botryoidal, the spherules very quickly swelling and coalescing. Underleaves ca. 0.45–0.5× the leaves, 2–3-fid to ca. 0.5, the lobes asymmetrical, with 1 or 2 lobes smaller and ending in a slime papilla; disc 3 cells high.
Plants dioecious. Androecia not seen. Gynoecia with bracts of innermost series much larger than leaves, bifid to 0.4–0.45; lobes terminating in a uniseriate row of 3 cells, the lobe margins with up to 4 strong teeth and at times an accessory lobule; disc margins with a few small teeth; bracteole similar to bracts but a little smaller. Perianth long-exserted, trigonous, somewhat but not strongly narrowed to the mouth, the mouth dentate-ciliolate, the teeth discrete from one another and terminating in a single cell or a uniseriate row of 2 somewhat elongated cells, the terminal cell rounded at the summit.
Capsule wall 2-, locally 3-stratose; outer layer of cells with sharply defined two-phase development, the longitudinal walls with continuous sheets of secondary wall material and strong nodular thickenings, alternating with primary walls with thickenings absent; inner layer of cells with a few to several semiannular bands and (commonly) nodular thickenings.
Spores and elaters not seen.
Distribution and Ecology : Endemic to New Zealand: North Island (405–480 m). Known only from Auckland and Volcanic Plateau EPs.
Known only from a few collections: the type locality at Tauranga (Bay of Plenty), the Kaimai Ra. (spur ESE of Ngatamahinerua, headwaters of Poupou Stream, 405 m), Kaingaroa Plain near Waiotapu and Utuhina Stream west of Rotorua (ca. 450 m) as well as the Old Kaimai Road. At the Kaimai Ra. site the species was found on bare clay of a drainage channel in a stream valley under an open canopy of Beilschmiedia tawa and Weinmannia silvicola; subcanopy dominants were Schefflera digitata, Cyathea dealbata and C. smithii, and a shrub layer consisted of Freycinetia baueriana and Cortaderia. Locally common at Old Kaimai Road (boundary of Kaimai-Mamaku Forest Park, 460–480 m) on roadside clay banks as well as the raised roadside clay bed. At the Utuhina Stream site it was found “on a bank in bush” with Solenostoma inundatum, Campylopus clavatus and Isotachis montana. Schuster (2000a) recorded the species from Tongariro Natl. Park. The species apparently is restricted to exposed fine-grained soils.
Comments : Plants of this species have a superficial resemblance to Cephalozia, but may be immediately distinguished from that genus by the presence of well-developed underleaves, which are up to 0.5 the leaf size, the position of rhizoids at underleaf bases and the frequent trifid leaves.
Paracromastigum macrostipum may be distinguished from the other member of subgenus Austrocephalozia in our area, P. furcifolium, by the presence of reddish brown pigments, the rather densely imbricate leaves, with acute lobes that terminate either in a single cell or a uniseriate row of 2 subisodiametric cells and the higher underleaf disc (3 cells high).
Oil-bodies appear to behave very similar to those of Paracromastigum furcifolium. In both species oil-bodies are present only in some cells, inconspicuous, up to 3 per cell and conspicuously botryoidal. Also, oil-body breakdown in both species is similar, with spherules very quickly swelling and coalescing.
