Pellaea calidirupium

Pteridaceae

Pellaea calidirupium Brownsey & Lovis

Link to Australian Plant Name Index for publication details and synonyms: https://id.biodiversity.org.au/name/apni/154091

Rock Sickle Fern

Rhizome long-creeping; scales ovate, to 2 mm long, with a midrib of black occluded cells and margins of paler brown open cells. Fronds 20–50 cm long, markedly but inconstantly dimorphic; sterile fronds usually shorter and with only 4–12 pinnae. Stipe 10–23 cm long (45–55% length of frond), 1–2 mm diam., 5–10 mm apart; stipe and rachis dark red-brown throughout, bearing scales and uniseriate hairs; scales to c. 4 mm long, dense, appressed, antrorse, narrowly ovate with long filiform apices, pale to mid-brown (whitish to pale-cream coloured when immature). Lamina 1-pinnate, narrowly elliptic, with 15–40 shortly-stalked pinnae, glossy dark green on upper surface, paler green beneath, with scattered narrowly-acuminate scales on both surfaces; stalks of basal pinnae at least 1.5 mm long; juvenile and mature sterile pinnae ±round or oblong with obtuse to emarginate apices and truncate bases; terminal pinna sometimes greatly enlarged. Fertile pinnae ±triangular, 14–30 mm long, 7–12 mm wide, progressively reducing in length and width from base to apex of frond, symmetric about midrib, rarely slightly falcate; base truncate to cordate; margins entire or minutely toothed; apex acute or acuminate, rarely mucronate; lower fertile pinnae widely spaced on 1.5–4.5 mm long stalks; upper pinnae close together and almost sessile. Sorus a continuous marginal band 1–2 mm wide, sometimes confluent at apex of pinna; indusium marginal, membranous, obscured by sporangia at maturity. Spores trilete, ±spherical, echinate. 

Occurs in Tas, Vic, NSW and southern QLD with putative records from the Atherton Tablelands in NE QLD. Endemic to Australia and New Zealand.

Terrestrial in soil pockets or lithophytic in rock crevices, usually in exposed rocky areas on dolerite or granite.

Pellaea nana, P. falcata and P. paradoxa

1a. rachis scales and hairs mid- to dark-brown, spreading = 2

1b. rachis scales and whitish to pale-brown appressed = 3

2a. rachis scales mostly 3–4 mm long, pinnae 22–56 mm long = Pellaea falcata

2b. rachis scales mostly 1–2.5 mm long, pinnae 5–25 mm long = Pellaea nana

3a. pinnae 20–60 mm long; all lateral pinnae the same length = Pellaea paradoxa

3b. pinnae 14–30 mm long; lateral pinnae reducing in length and width towards the frond apex = Pellaea calidirupium