Asplenium × Microdon

''Asplenium'' is a genus of about 700 species of ferns, often treated as the only genus in the family Aspleniaceae, though other authors consider '' Hymenasplenium'' separate, based on molecular phylogenetic analysis of DNA sequences, a different chromosome count, and structural differences in the rhizomes. The type species for the genus is '' Asplenium marinum''.

The most common vernacular name is spleenworts, applied to the more "typical" species. '' A. nidus'' and several similar species are called bird's-nest ferns, the ''Camptosorus'' group is known as walking ferns, and distinct names are applied to some other particularly well-known species.

Etymology

From New Latin ''asplenium'' (“spleenworts”), Linnaeus's adjustment of Latin ''asplenon'' (“spleenwort”), from Ancient Greek ἄσπληνον (''ásplēnon'', “spleenwort”), from ἀ- (''a-'', “un-”) + σπλήν (''splḗn'', “spleen”) + -ον (''-on'', “-um”), from its use to cure anthrax in livestock.

Taxonomy and genetics

Many groups of species have been separated from ''Asplenium'' as segregate genera. These include ''Camptosorus'', ''Ceterach'', ''Phyllitis'', and ''Tarachia'', but these species can form hybrids with other ''Asplenium'' species and because of this are usually included in a more broadly defined ''Asplenium''.

Some of the older classifications elevate the Aspleniaceae to the taxonomic rank of order as Aspleniales. The newer classifications place it in the subordinal group called eupolypods within the order Polypodiales. Within the eupolypods, Aspleniaceae belongs to a clade informally and provisionally known as eupolypods II.

It has been found that in some species, the chloroplast genome has evolved in complex and highly unusual ways. This makes standard cladistic analyses unsuited to resolve the phylogeny of that particular group of ferns, and even very sophisticated computational phylogenetics methods yield little information. In addition to hybridization running rampant in parts of this genus, there are also some species like the mother spleenwort (''A. bulbiferum'') or '' A. viviparum'' which mainly reproduce asexually, essentially cloning themselves over and over again. While most are diploid or tetraploid, some species (e.g. '' A. shuttleworthianum'') are octoploid.

Uses

Both the scientific name and the common name "spleenwort" are derived from an old belief, based on the doctrine of signatures, that the fern was useful for ailments of the spleen, due to the spleen-shaped sori on the backs of the fronds. "-wort" is an ancient English term that simply means "plant" (compare German ''-wurz''). The plants were thought to cause infertility in women.

Vitruvius relates the story of the name thus:

... certain pastures in Crete, on each side of the river Pothereus, which separates the two Cretan states of Gnosus and Gortyna. There are cattle at pasture on the right and left banks of that river, but while the cattle that feed near Gnosus have the usual spleen, those on the other side near Gortyna have no perceptible spleen. On investigating the subject, physicians discovered on this side a kind of herb which the cattle chew and thus make their spleen small. The herb is therefore gathered and used as a medicine for the cure of splenetic people. The Cretans call it ἄσπληνον.

A few of these ferns have some economic importance in the horticulture trade. The bird's-nest ferns ('' A. nidus'' and several very similar, closely related species) are commonly found for sale as a house plant. The Australian mother spleenwort (''A. bulbiferum'') is sometimes available at greenhouses, and is of interest, along with the related '' A. viviparum'', for the many small bulblets borne on the fronds that may grow into new plants. This characteristic is also shared with the eastern North American walking fern (''A. rhizophyllum'') and several Mexican species including '' A. palmeri''. The ebony spleenwort ''A. platyneuron'' is also sometimes sold in nurseries as a hardy plant. However, many spleenworts are epipetric or epiphytic and difficult to cultivate.

''Asplenium'' species are used as food plants by the larvae of some Lepidoptera species including '' Batrachedra bedelliella'' which feeds exclusively on ''A. nidus''. For diseases of ''Asplenium'', see List of foliage plant diseases (Polypodiaceae).

Selected species

* '' Asplenium adiantum-nigrum'' L. – black spleenwort (= ''A. lucidum'' Burm.f.)
** ''Asplenium adiantum-nigrum'' ssp. ''adiantum-nigrum''
** ''Asplenium adiantum-nigrum'' ssp. ''serpentini'' (Tausch) Koch
* '' Asplenium adulterinum'' Milde – ladder spleenwort
* '' Asplenium aequibasis'' ( C.Chr.) J.P.Roux
* '' Asplenium aethiopicum'' ( Burm.f.) Bech.
* '' Asplenium africanum''
* '' Asplenium × alternifolium'' Wulf.
* '' Asplenium anceps'' owe ex Hook. et Grev. Page (1971)/small>
* '' Asplenium angustum'' Sw.
* '' Asplenium antiquum'' Makino
* '' Asplenium arcanum'' A.R.Sm.
* '' Asplenium ascensionis'' S.Watson
* '' Asplenium attenuatum'' Sw.
* '' Asplenium aureum'' (sometimes in ''Ceterach'')
* '' Asplenium auritum'' R.Br.
* '' Asplenium australasicum'' (J.Sm.) Hook. – crow's-nest fern
** ''Asplenium australasicum'' f. ''australasicum''
** ''Asplenium australasicum'' f. ''robinsonii''
* '' Asplenium azoricum'' Lovis, Rasbach & Reichst.
* '' Asplenium bifrons'' Sodiro
* '' Asplenium billottii'' – lanceolate spleenwort
* '' Asplenium bipinnatifidum''
* '' Asplenium brachycarpum''
* '' Asplenium bradleyi''
* '' Asplenium bulbiferum'' – mother spleenwort, hen and chickens fern, ''mouku'' ( Māori)
* '' Asplenium carnarvonense'' - Brownsey
* '' Asplenium caudatum''
* '' Asplenium ceterach'' – rustyback fern (sometimes in ''Ceterach'')
* '' Asplenium chathamense'' Brownsey
* '' Asplenium chihuahuense'' Baker
* '' Asplenium compressum'' Sw.
* '' Asplenium congestum'' C.Chr.
* ''Asplenium corderoanum''
* '' Asplenium crinicaule''
* '' Asplenium cristatum''
* '' Asplenium cuneifolium'' Viv. (= ''A. forsteri'' ''auct. non'' Sadl.) – serpentine spleenwort
* '' Asplenium cymbifolium''
* '' Asplenium daghestanicum'' H.Christ – Dagestanian spleenwort
* '' Asplenium dalhousiae'' (sometimes in ''Ceterach'')
* '' Asplenium dareoides''
* '' Asplenium daucifolium'' Lam. – Mauritius spleenwort
* '' Asplenium difforme'' R.Br.
* '' Asplenium fissum''
* '' Asplenium dimorphum'' Kunze – Norfolk Island Spleenwort
* '' Asplenium divaricatum''
* ''Asplenium dregeanum''
* '' Asplenium × ebenoides'' R.R.Scott
* '' Asplenium ecuadorense'' Stolze
* '' Asplenium feei'' Kunze ex Fée
* '' Asplenium fissum''
* '' Asplenium flabellifolium'' Cav. – necklace fern
* '' Asplenium flaccidum'' G.Forst. – weeping spleenwort, hanging spleenwort
* '' Asplenium fontanum'' (L.) Bernh. – smooth rock spleenwort
* '' Asplenium forisiense'' – rock spleenwort
* '' Asplenium formosum''
* '' Asplenium gemmiferum'' Schrad.
* '' Asplenium × germanicum''
* '' Asplenium gueinzii'' Mett.
* '' Asplenium goudeyi'' Lord Howe Island
*'' Asplenium haughtonii'' – Barn Fern
* '' Asplenium hemionitis''
* '' Asplenium hermannii-christii'' Fomin – Hermann Christ's asplenium
* '' Asplenium hookerianum'' Colenso
* '' Asplenium hybridum''
* '' Asplenium incisum''
* '' Asplenium × jacksonii'' Alston – Jackson's spleenwort (sterile, triploid hybrid between '' Asplenium adiantum-nigrum'' and '' Asplenium scolopendrium'')
* '' Asplenium × kenzoi'' - oni-hinokishida, cultivated in Japan
* '' Asplenium komarovii'' - Akasawa
* '' Asplenium laciniatum''
* '' Asplenium lamprophyllum'' Carse
* '' Asplenium laserpitiifolium'' – Johnston River fern
* '' Asplenium lepidum'' C.Presl
* '' Asplenium listeri'' – Christmas Island spleenwort
* '' Asplenium longissimum''
* '' Asplenium lucidum''
* '' Asplenium lunulatum'' – Hen-and-chicks
* '' Asplenium lyallii''
* '' Asplenium macedonicum''
* '' Asplenium majoricum''
* '' Asplenium marinum'' – sea spleenwort
* '' Asplenium × microdon'' T Moore – Moore's spleenwort (hybrid between ''Asplenium scolopendrium'' and ''Asplenium obovatum'' subsp ''lanceolatum'')
* '' Asplenium milnei'' Carruth
* '' Asplenium montanum'' – mountain spleenwort
* '' Asplenium musifolium''
* '' Asplenium nidus'' – bird's-nest fern
* '' Asplenium normale''
* '' Asplenium obliquum''
* '' Asplenium oblongifolium'' Colenso – shining spleenwort (= ''A. lucidum'' ''auct. non'' Burm.f., ''sensu'' G.Forst.)
* '' Asplenium obovatum''
* '' Asplenium obtusatum'' G.Forst.
** ''Asplenium obtusatum'' ssp. ''northlandicum'' (Brownsey) Ogle (possibly distinct species)
** ''Asplenium obtusatum'' 'Chile' (possibly distinct species, sometimes included in ''A. obliquum'')
* '' Asplenium oligolepidum'' C.Chr. (= ''A. lucidum'' ''auct. non'' Burm.f., ''sensu'' G.Forst.)
* '' Asplenium oligophlebium''
* '' Asplenium onopteris'' L. – western black spleenwort, Irish spleenwort (sometimes included in ''A. adiantum-nigrum'')
* '' Asplenium pacificum''
* '' Asplenium paleaceum'' R.Br. – chaffy spleenwort
* '' Asplenium palmeri''
* '' Asplenium parvum''
* '' Asplenium petrarchae''
* '' Asplenium pinnatifidum'' – lobed spleenwort
* '' Asplenium planicaule''
* '' Asplenium platybasis'' Kunze ex Mett.
* '' Asplenium platyneuron'' – ebony spleenwort
* '' Asplenium polyodon'' G.Forst. – sickle spleenwort
* '' Asplenium praemorsum''
* '' Asplenium prolongatum'' Hook.
* '' Asplenium pteridoides'' Baker
* '' Asplenium resiliens'' – black-stemmed spleenwort
* '' Asplenium rhizophyllum'' – American walking fern (sometimes in ''Camptosorus'')
* '' Asplenium richardii''
* '' Asplenium ruprechtii'' – Asian walking fern (sometimes in ''Camptosorus'')
* '' Asplenium ruta-muraria'' L. – wall-rue
* '' Asplenium rutifolium''
* '' Asplenium sagittatum'' – Mule's spleenwort (sometimes in ''Phyllitis'')
* '' Asplenium sandersonii'' Hook.
* '' Asplenium × sarniense'' Sleep Guernsey Spleenwort
* '' Asplenium schizotrichum'' Copel.
* '' Asplenium schweinfurthii''
* '' Asplenium scleroprium''
* '' Asplenium scolopendrium'' – hart's-tongue fern (sometimes in ''Phyllitis'')
** ''Asplenium scolopendrium'' var. ''americanum'' – American Hart's-tongue
* '' Asplenium seelosii''
* '' Asplenium septentrionale'' – forked spleenwort, northern spleenwort
* '' Asplenium septentrionale × trichomanes'' Wulf.
* '' Asplenium serra''
* '' Asplenium serratum'' – wild bird's-nest fern
* '' Asplenium sessilifolium''
* '' Asplenium shuttleworthianum'' Kunze
* '' Asplenium simplicifrons'' F.Muell.
* '' Asplenium splendens''
* '' Asplenium surrogatum'' P.S.Green
* '' Asplenium tenerum'' G.Forst.
* '' Asplenium terrestre''
* '' Asplenium theciferum'' (Kunth) Mett.
* '' Asplenium thunbergii''
* ''Asplenium trichomanes'' – maidenhair spleenwort
** ''Asplenium trichomanes'' ssp. ''quadrivalens'' D.E. Meyer
** ''Asplenium trichomanes'' ssp. ''trichomanes''
** ''Asplenium trichomanes'' subsp. ''coriaceifolium''
* '' Asplenium trilobum ''Cav.
* '' Asplenium tutwilerae'' B.R.Keener & L.J.Davenport
* '' Asplenium unisorum'' (Wagner) Viane
* '' Asplenium vespertinum''
* '' Asplenium vieillardii'' Mett.
* '' Asplenium virens''
* '' Asplenium viride'' – green spleenwort
* '' Asplenium vittiforme''
* '' Asplenium viviparum''
* '' Asplenium yoshinagae'' Makino

See also

* Mount Asplenium
* '' Phyllocladus aspleniifolius'' (Celery-top Pine, a conifer with ''Asplenium''-like leaves)
* ''Asplenium'' hybrids

References

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Epiphytes
Fern genera
Taxa named by Carl Linnaeus