Adiantum philippense

Pteridaceae

Adiantum philippense L.

Link to Australian Plant Name Index for publication details and synonyms: https://id.biodiversity.org.au/name/apni/116281

Maidenhair Fern

Rhizome short-creeping, erect or suberect, to 5 mm diam.; scales yellow to dark red-brown, often bicolorous, with entire or scarcely serrate margins and blunt apical seta. Fronds tufted, arching, to 40 cm long. Stipe to 15 cm long, glabrous. Lamina 1-pinnate, narrowly triangular, 10–22 cm long, 3–6 cm wide; rachis glabrous, occasionally extended past lamina and ending in proliferous bud. Pinnules subdimidiate, rounded-trapeziform or semi-circular to almost lunate, glabrous; basal angle acute on upper pinnules, usually obtuse on lower ones; distal margin entire or irregularly lobed, scarcely denticulate when sterile; stalks articulated to rachis. Sori 1–10 per segment, occupying entire lobe margin; soral flaps linear to sublunate, glabrous. Spores 64 per sporangium, dark brown; perine granulate, loosely adhering to exine; largest diam. (35–) 52.3 (–68) µm. 

In Australia this species occurs between Torres Strait, Halifax Bay and Chillagoe.

Terrestrial or lithophytic in low altitude rainforest, open forest or open sclerophyll woodland, usually near rocks or the base of trees near a watercourse. This species is often deciduous, even in wet areas. It spreads prolifically from the apices of fronds to form colonies.

This is cultivated ornamental fern in tropical, subtropical and temperate areas. It can be grown in a container or in the ground in a greenhouse or in semi-shaded to shaded areas of the garden. It is usually winter or drought deciduous. This species is readily reproduced from offsets that form where the fronds touch the ground.

Key to some Adiantum species of tropical Australia.

1a. Fronds pinnate = Adiantum philippense

1b. Fronds bipinnate or higher = 2

2a. Pinnules flabellate to rounded = 3

2b. Pinnules obliquely oblong to rhomboid = 5

3a. Soral flaps broadly attached to lamina and situated on the ends of lobes with incisions between them = Adiantum capillus-veneris

3b. Soral flaps reniform and narrowly attached to lamina and situated in incisions of the lamina margin with lobes between them = 4

4a. Rhizome long creeping, rhizome scales translucent with entire margins, plants stoloniferous and spreading, pinnae pale bright green when mature = Adiantum aethiopicum

4b. Rhizome short creeping, rhizome scales opaque with denitculate margins, not stoloniferous plants tufted, pinnae dark green when mature = Adiantum atroviride

5a. Rhizome long creeping, fronds scattered = 6

5b. Rhizome not long creeping, fronds tufted = 7

6a. Primary pinnae progressively reducing in length from base to apex of frond resulting in a triangular lamina = Adiantum formosum

6b. Primary pinnae equal in length resulting in an ovate lamina = Adiantum silvaticum

7a. Pinnae soft and membraneous with fine black hairs on the undersurface, root tubers present, often proliferous, stipe smooth = Adiantum diaphanum

7b. Pinnae herbaceous to coreaceous with white hairs, root tubers absent, not proliferous, stipe not smooth = Adiantum hispidulum