Microsorum grossum

Polypodiaceae

Microsorum grossum (Langsd. & Fisch.) S.B.Andrews

Link to Australian Plant Name Index for publication details and synonyms: https://id.biodiversity.org.au/name/apni/119193

Rhizome long-creeping, 5–7 mm diam., fleshy, green, scaly when young. Scales scattered, ovate, 2.5–8 mm long, 1–3 mm wide, appressed or ±bullate, deciduous, thin, pale brown to mid-brown, often opalescent; margins dentate; apex shortly acuminate. Fronds to 190 cm long, 1–6 (–10) cm apart. Stipe 8–90 cm long, pale, glossy, glabrous except for a few scales at the base. Lamina deeply pinnatifid, with 5–10 (–15) pairs of lobes and a similar terminal one, rarely simple, pale green, thinly coriaceous, glabrous except for a few scattered scales on midrib and costae. Lateral lobes strap-shaped, 3–23 cm long, 0.8–4 (–5) cm wide, tapering to an acute or obtuse apex and usually narrowing a little towards base; margins entire or undulate. Terminal lobe often elongate. Costae prominent; other veins obscure. Sori to 5 mm diam., round or ±elliptic, in (1–) 2 (–3) irregular rows on each side of costae of at least some lobes, especially the terminal lobe, with some sori also on the wing between lobes, impressed a little into lamina, forming truncate protuberances on the upper surface. Spores 37.5–80 µm long, 20–62.5 µm wide.

Occurs in N WA, NT and QLD from Torres Strait to Stradbroke Island. Also in New Guinea and the Pacific Islands, as well as probably in tropical Africa and Asia.

Terrestrial or somtimes litophytic, commonly observed growing in sand dunes in beach scrubs.

Easily cultivated in a container or ground in full sun or part shade in a tropical or subtropical garden or fernery. This plant is very hardy in dry conditions and several interesting leaf cultivars are available.

Frequently confused with Microsorum scolopendria, from which it can be distinguished by its thicker rhizome, terrestrial habit and larger paler rhizome scales.