Gleichenia inclusisora

Detailed description

Terrestrial fern. Rhizomes long-creeping, 1–3mm diameter, brown, with stipes arising at intervals of 5–90mm (or more), scaly. Rhizome scales sparse to numerous, 0.5–1.2 × 0.5–0.8mm, ovate to orbicular, dark brown to nearly black, margins entire or nearly so, peltate, bullate. Stipes 40–1100 mm long, 1.0-2.5mm diameter, widest distally, proximally dark brown, distally straw-green when young or brown when old, glabrous except for occasional, proximal scales that are like those of the rhizome. Rachis buds 2.0–3.1 × 1.2–2.1 mm, often not producing a rachis so that fronds form a single tier of pinnae, but sometimes 2–4 tiers, with rachis inter-tier lengths of 15–280 mm. Rachis bud scales 1.5–2.5 × 1.0–1.5 mm, ovate, marginate, dark brown with a pale brown or clear margin, ciliate to erose, peltate. Pinnae 50–950+ × 50–300 mm, with 0–6 pseudodichotomous branchings. Pinna buds similar to rachis buds but generally smaller. Distal costae (nerves) appearing tetragonal or nearly so on the adaxial surface, with lateral ridges. Proximal costae glabrescent, straw-green when young, brown when old. Gamma costae 10–40mm long, with 0–4 pairs of ultimate leaflets; indument similar to beta costae but sparser. Beta costae 25–135mm long, with 5–26 pairs of ultimate leaflets and a terminal ultimate leaflet 10–44 mm long; adaxially with long-ciliate, reduced scales that are abundant and orange-brown when young or sparse and white when old; abaxially with a mixture of scales like those on the pinna buds and ultimate segments, glabrescent. Longest ultimate leaflets 18–59mm long, with 15–47 pairs of ultimate segments. Alpha costae adaxially glabrous (or with occasional reduced scales like those of the beta costae when young), abaxially with scales like those of the ultimate segments. Ultimate segments 0.7–1.4 × 0.9–1.4 mm, adaxially green and glabrous, abaxially white (sometimes glaucous) and abundantly (when young) to sparsely scaly, abaxial surface flat to recurved 90° but lateral margins at most only slightly raised (not pouched), apices rounded and revolute. Scales on abaxial surface of ultimate segments 0.3–0.8 × 0.3–0.6 mm, orbicular to ovate, with dark brown centre and pale brown margins, long-ciliate, peltate, bullate; similar but larger (to 1.0 mm long), ovate scales covering young ultimate leaflets. Sori 0.4–0.5 mm diameter, each comprising three pale yellow sporangia embedded to c. ¾ of their depth in a pit within the abaxial surface of the lamina; one sorus per ultimate segment, in the proximal acroscopic corner. Spores trilete, yellow.