Angiopteris evecta (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Angiopteris evecta (G. Forst.) Hoffm.

Protologue: Commentat. Soc. Regiae Sci. Gott. 12: 29, t. 5 (1796).

Family: Marattiaceae

Chromosome number: 2n= 80, 160

Polypodium evectum G. Forst. (1786), Angiopteris palmiformis (Cav.) C. Chr. (1937).

• King fern, giant fern, elephant fern (En, Am)
• Indonesia: paku gajah (general), sibakkat-laggai (Siberut)
• Malaysia: paku gajah
• Papua New Guinea: faflako (Wantipi, Sepik), sagonefos
• Philippines: pakong kalabaw (Tagalog), salagisog, andawigay (Binukid). Singapore: paku gajah
• Thailand: wan kip raet (general), wan kip ma, kip ma lom (northern).

A. evecta is widespread in the Old World tropics from Madagascar and tropical Asia, throughout South-East Asia, to Australia and Polynesia. Elsewhere it is sometimes naturalized, e.g. in Jamaica and Hawaii.

The starchy stipules of A. evecta have been eaten in times of starvation in Papua New Guinea and have been used for brewing alcohol, the young leaves are eaten in Ambon and croziers as an ingredient of stew in the Philippines. Many traditional medicinal uses are known: a decoction of the rhizome has been used to arrest the discharge of blood after a miscarriage and rhizome boiled with green beans to treat beriberi. In Siberut (Indonesia) a decoction of the leaves of A. evecta and Diplazium esculentum (Retz.) Swartz is given to pregnant women to treat backache, but to treat heavy backache a concoction is made of the root of A. evecta , the inflorescence of Etlingera punicea (Roxb.) R.M. Smith and Hedychium coronarium Koenig, and the leaves of Kaempferia galanga L. The rhizome is chewed together with ginger and betel to treat spitting blood, especially if caused by poisoning. The pounded stem is used as an ingredient for cough medicine and the stipules as a poultice for abdominal pain. In Papua New Guinea, leaves are bound to fractured limbs to aid healing and the mucilage from the leaves is also applied to the body to reduce high fevers; fresh leaves are used as a poultice for stomach-ache. In the Philippines pulverized young tender leaves are used as a poultice for swellings. A. evecta is cultivated as an ornamental in South-East Asia.

A. evecta is not cultivated commercially and no international trade exists. Plants grow wild or as an ornamental in domestic gardens.

No nutritional analysis of A. evecta is known; the stipules contain starch grains.

A fleshy, robust, terrestrial fern, developing a stout stem and tall bipinnate leaves (up to 6 m long). Rhizome short, fleshy, massive, erect, forming a clump up to 1 m tall and 0.5(-1) m in diameter, partly concealed by persistent fleshy stipules of previous and present leaves. Leaves clustered at rhizome apex; petiole about 1/3 of the leaf length, 1-1.5 m × 5 cm or more, base swollen, with a pair of fleshy, rounded stipules 5 cm long and 7 cm wide, dark green with scattered whitish streaks, glabrous but when young more or less covered with appressed, soft, brown, linear scales and hairs that are soon deciduous; blade arching, up to 6 m × 2 m, usually bipinnate, upper side dark green, slightly paler at underside; rachis green, sparsely and deciduously scaly like the petiole, especially on the underside; smaller rachides narrowly alate distally; stipes of pinnae and pinnules swollen at the base; pinnae oblong-oblanceolate in outline, 1 m long or longer, midrib with 3 grooves above, terete below; pinnules usually 30-36 on a side, 2-3 cm apart, linear-oblong, up to 20 cm × 2.5 cm, inequilateral at the base, margin serrate with a small, blunt tooth at each vein, apex acuminate-attenuate and serrulate; veins simple or forked, raised and translucent; recurrent veins slender, usually conspicuous between and parallel with main lateral veins. Sori short, submarginal in an irregular line 0.5-1.5 mm from the edge, on lateral veins, composed of a double row of 3-7 sporangia that dehisce by vertical slits to release several thousands of spores per sporangium; receptacular hairs branched, usually conspicuous. Spores trilete, globose, the surface low tuberculate to rugate.

A germinating spore of A. evecta produces a flat, large, glabrous, dark green gametophyte (prothallus) up to several cm long and resembling an anthocerotoid liverwort. The gametophyte is mycorrhizal and assumed to be as slow growing and long-lived in the wild as it is in cultivation. The young fern embryo (sporophyte) emerges through the dorsal surface of the gametophyte. The first leaves borne by the sporophyte are fan-shaped, later ones are pinnate, mature leaves are bipinnate. The leaves are long-lived. The degree of pinnation may be affected by environmental factors and varies within a leaf or between leaves. Immature leaves often bear sporangia. Plants are long-lived, e.g. one individual cultivated in the Bogor Botanical Garden (Indonesia) is over 50 years old.

For Angiopteris Hoffm. about 200 species have been described (including for example in South-East Asia, A. amboinensis de Vriese, A. angustifolia C. Presl, A. ceracea Alderw., A. lygodiifolia Rosenst., A. palmiformis (Cav.) C. Chr.), but the specific classification is still in confusion. Some authors consider all described species as variations of only one species A. evecta . The general characters of all so-called species are very much alike but they differ in details. The original A. evecta was found in Tahiti. In South-East Asia most specimens belong to A. evecta , with pinnules usually 2.5 cm wide and the recurrent veins not translucent beyond the sori. Specimens with pinnules about 1.5 cm wide and recurrent veins translucent almost to the midrib of the pinnule have been classified as A. angustifolia Presl which is commonly considered as a distinct species growing particularly in mountainous regions of over 1200 m altitude. The "recurrent veins" are lines which run from the margin between the true veins, starting in the sinus between two marginal teeth; they are often translucent; their structure is the same as that of the edge of the leaflet and possibly they indicate that once Angiopteris had more finely divided leaves but the finer divisions have joined together, the edge-characters persisting in the junctions. Plants with dense scales borne on podia on the petiole, or with simply pinnate leaves, or much broader pinnules, are referred to other species. Sterile plants of the closely related genus Marattia Swartz may be confused with Angiopteris .

A. evecta is a plant of wet tropical and subtropical primary and secondary forests. It often occurs on shady stream and river banks or steep clay slopes, along trails and edges of open areas in the forest, from sea-level up to 1200 m altitude. Introduced in gardens outside its natural distribution area, A. evecta is known to escape easily and grows from spores transported over large distances (over 50 km) when the climate is favourable. On the Hawaiian island Maui, the spores were dispersed by wind to several nature reserves and it is feared that the fern may soon spread to new areas and occupy niches formerly occupied by endemic Hawaiian ferns on all the islands.

Propagation of A. evecta from spores is slow. Vegetative propagation through the growth of adventitious buds on the stipules is very effective and may be seen in wild plants whose stipules have been damaged by foraging pigs. Plantlets developing from the swollen leaf bases can be removed and planted separately in loamy soil, rich in humus. Portions of the stipule placed with the cut side down on soil or compost and kept damp, will eventually sprout.

A. evecta is not cultivated commercially, but it is a handsome and impressive garden ornamental. It tolerates warm to cool conditions, but should not be exposed directly to the sun. Leaves droop dramatically under drought stress and the fern does not tolerate dry conditions. Adequate water and humidity appear more important than shade.

A. evecta grown in a greenhouse sometimes suffers from southern blight by Corticium rolffsii . A gall mite causes a kind of erineum of a callus nature on the underside of the leaves.

Neither germplasm collections nor breeding programmes are known for A. evecta .

The medicinal value of parts of A. evecta that are used in traditional medicine may merit further pharmaceutical investigation. The use of the starch in the stipules for famine food or brewing alcohol has apparently been superseded by the availability of better sources of starch. The prospects for ornamental use of A. evecta are good.

• Bidin, A.A., 1987. Paku-pakis ubatan di semenanjung Malaysia [Medicinal ferns of Peninsular Malaysia]. Dewan Bahasa dan Pustaka, Kementerian Pendidikan Malaysia, Kuala Lumpur, Malaysia. pp. 28-30.
• Holdsworth, D.K., 1974. Medicinal plants of Papua New Guinea. Technical Paper No 175. South Pacific Commission, Noumea, New Caledonia. p. 71.
• Holttum, R.E., 1966. A revised flora of Malaya. 2nd Edition. Vol. 2. Ferns of Malaya. Government Printing Office, Singapore. pp. 43-45.
• Tagawa, M. & Iwatsuki, K., 1979. Marattiaceae. In: Tagawa, M. & Iwatsuki, K. (Volume editors), 1979-1989. Pteridophytes. In: Smitinand, T., Larsen, K. (Series editors): Flora of Thailand. Vol. 3. Forest Herbarium, Royal Forest Department, Bangkok, Thailand. pp. 41-43.
• Zamora, P.M. & Co, L., 1986. Guide to Philippine flora and fauna. Vol. 2. Economic ferns, endemic ferns, gymnosperms. Natural Resources Management Center, Ministry of Natural Resources and University of the Philippines, Goodwill Bookstore, Manila, The Philippines. p. 19.

W. P. de Winter & P.C.M. Jansen