| Asplenium nidus | |
|---|---|
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| Asplenium nidus in thePhilippines | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Division: | Polypodiophyta |
| Class: | Polypodiopsida |
| Order: | Polypodiales |
| Suborder: | Aspleniineae |
| Family: | Aspleniaceae |
| Genus: | Asplenium |
| Species: | A. nidus |
| Binomial name | |
| Asplenium nidus | |
| Synonyms[2] | |
Asplenium nidus is anepiphyticspecies offern in thefamily Aspleniaceae,native to tropical southeastern Asia, eastern Australia, Hawaii (ʻēkaha inHawaiian),[3][4] Polynesia,[5] Christmas Island,[6] India,[7] and eastern Africa. It is known by thecommon namesbird's-nest fern[1][8] (a name shared by some other aspleniums) or simplynest fern.[8]
Asplenium nidus forms large simplefronds visually similar tobanana leaves, with the fronds growing to 50–150 centimetres (20–59 in) long and 10–20 centimetres (3.9–7.9 in) broad, with occasional individuals up to 6.6 feet (two meters) in length by up to two feet (61 centimeters) width[9] They are light green, often crinkled, with a black midrib, and exhibitcircinate vernation.Spores develop insori on the underside of the fronds. These sori form long rows extending out from the midrib on the back of the outer part of thelamina (frond). The fronds roll back as they brown and create a massive leaf nest in the branches and trunks of trees. The subspecies or variety A.n. taeniophyllum of thePhilippines has fronds up to 4ft 5 in (135 centimeters) in length while only 1.5 inches (3.7 centimeters) wide.[10]
Linnaeus was the first todescribe bird's-nest fern with thebinomialAsplenium nidus in hisSpecies Plantarum of 1753.[11]
A global phylogeny ofAsplenium published in 2020 divided the genus into eleven clades,[12] which were given informal names pending further taxonomic study.A. nidus belongs to the "Neottopteris clade",[13] members of which generally have somewhat leathery leaf tissue. While the subclades of this group are poorly resolved, several of them share a characteristic "bird's-nest fern" morphology with entire leaves and fused veins near the margin.[14] Both the 2020 study[14] and a 2015 molecular study found thatA. nidus is polyphyletic, meaning that some populations were not closely related to others—A. nidus from Madagascar, Vanuatu and New Guinea were more closely related to other species than each other. Hence a revision with sampling of the species across its range was required to delineate the taxon and identify cryptic species.[15]A. nidussensu lato forms a clade with the morphologically similarA. australasicum, but other bird's-nest ferns such asA. antiquum andA. phyllitidis form a separate subclade which is not particularly closely related.[13]
Asplenium nidus is native to east tropical Africa (in Tanzania, inclusive of theZanzibar Archipelago); temperate and tropical Asia (in Indonesia; East Timor; the island ofKyushu, and theRyukyu Islands of Japan; Malaysia; the Philippines; Taiwan; and Thailand); and in northern Australia and the Pacific Islands.[8]
Asplenium nidus can survive either as anepiphyte orterrestrial plant, but typically grows on organic matter. This fern often lives inpalm trees, where it collects water andhumus in itsleaf-rosette.[5] It thrives in warm, humid areas in partial to full shade. It dislikes direct sunlight and likes to be in full shade on a south facing garden wall when in the southern hemisphere and the north facing in the northern hemisphere.[16]
With a minimum temperature of 10 °C (50 °F),Asplenium nidus is widely cultivated intemperate regions as ahouseplant.[17] However, many plants sold asA. nidus are actually the relatedAsplenium australasicum.[18]Asplenium nidus has gained theRoyal Horticultural Society'sAward of Garden Merit.[19]
Asplenium nidus has been used locally in folk medicine forasthma,sores,weakness, andhalitosis.[20]
The sprouts ofA. nidus are eaten in Taiwan, known as 山蘇, pronouncedshansu. (山 meaning "mountain", as inmountain vegetables). They may be stir-fried or boiled and are a traditionalaboriginal vegetable,[21] now popular enough to appear even on the menus of chain restaurants.[22]
The young fronds are eaten in the Polynesian islands, known asLuku inNiue,Laukatafa inTuvalu andLaumea inTokelau where it is often cooked together and eaten with coconut cream. The large fronds are also used in the wrapping and cooking of food.[23]
In Hong Kong, this species is under protection based onForestry Regulations Cap. 96A.
Media related toAsplenium nidus at Wikimedia Commons
Data related toAsplenium nidus at Wikispecies