Sticherus tener (R.Br.) Ching

Rhizomes long-creeping, 1.5–3 mm diameter; rhizome scales lanceate, 1.3–3.5 mm long, 0.2–0.7 mm wide, brown, ciliate, sometimes only shortly so, rarely ± entire. Fronds 200–630 mm long. Stipes 80–380 mm long, scaly proximally and/or distally or glabrous. Laminae 90–330 mm long, 90–340 mm wide, green on both surfaces, herbaceous, scaly. Rachis buds often not extending or occasionally extending once (rarely twice), scaly; sometimes pseudostipulate, with one or two costal segments on stipe below or level with rachis bud, rarely with additional costal segments near base of each flanking branch. Rachis bud scales lanceate, 1.3–2.7 mm long, 0.2–0.6 mm wide, brown, ciliate. Pinnae 90–190 mm long, 45–260 mm wide; with 1 (occasionally 2, rarely 0) pseudodichotomous fork (excluding growth from pinna buds); pinna buds not extending or rarely extending once. Proximal-most (primary) costae 12–34 mm long, with 3–8 pairs of costal segments. β costae (where not proximal-most costae) 22–55 mm long, with 6–13 pairs of costal segments. Ultimate leaflets narrowly ovate, 75–180 mm long, 16–40 mm wide, usually angustate, rarely caudate, falcate or straight; with 21–43 pairs of ultimate segments; pairs in centre of lamina diverging 40–70°. Abaxial surface of α costae scaly; scales lanceate, 1200–2450 µm long, 80–300 µm wide, brown, ciliate, persistent. Ultimate segments narrowly oblong, 10–22 mm long, 1.5–3 mm wide, arising at 70–85° from α costae, usually entire or rarely crenulate, acute; abaxial surface with pale stellate scales that resemble branched hairs, sometimes glabrescent. Sori 3–11 either side of midvein, usually with 3–4 sporangia each. Spores 33–37 µm long, 17–18 µm wide (5 samples, 2 populations).

The near right angle (70–85°) at which the ultimate segments arise from the α costae, and the 3–8 pairs of costal segments on the proximal-most costae distinguish Sticherus tener from the other Sticherus species in New Zealand.

The Sticherus tener populations near Westport occur within sandstone overhangs and on steep banks, amongst low woody vegetation. The Fiordland populations occur on poor soils under scrub or low, mixed forest, but extend into taller beech/podocarp forest.

Sticherus tener hybridises with S. cunninghamii (Brownsey et al. 2013). Hybrids can usually be recognised by their intermediate frond and scale characteristics and abnormally formed spores. Additionally, S. tener may be a diploid progenitor, together with S. flabellatus, of the tetraploid and putatively allopolyploid S. urceolatus (Brownsey et al. 2013).

No count has been made from New Zealand material of Sticherus tener, but n = 34 has been reported for Australian material (Garrett et al. 1998).

New Zealand material is not known to reach the frond size, the number of tiers of pinnae, or extent of pinna forking recorded for Australia (Garrett et al. 1998).