Classification
 Nomenclature
Scientific Name:
Asplenium L., Sp. Pl. 1078 (1753)
Synonymy:
  • = Phyllitis Hill, Brit. Herb. 525 (1757)
  • = Caenopteris Bergius, Acta Acad. Sci. Imp. Petrop. 1782(2): 249, t. 7 (1786)
  • = Darea Juss., Gen. Pl. 15 (1789)
  • = Ceterach Willd., Anleit. Selbststud. Bot. 578 (1804)
  • = Tarachia C.Presl, Epimel. Bot. 74 (1851)
  • = Pleurosorus Fée, Mém. Foug., 5. Gen. Filic. 179, t. 16c (1852)
  • = Chamaefilix Hill ex Farw., Amer. Midl. Naturalist 12: 239 (1931)
Type Taxon:
Asplenium marinum L.
Etymology:
From the Greek a (without) and splen (spleen), a reference to the supposed medicinal properties of these plants in reducing an enlarged spleen.
Vernacular Name(s):
spleenwort
 Description

Terrestrial, rupestral or epiphytic ferns. Rhizomes erect or short- to long-creeping, bearing clathrate scales. Fronds monomorphic or rarely dimorphic. Laminae undivided or 1-pinnate to 4-pinnate-pinnatifid, membranous (not NZ) or herbaceous to coriaceous (NZ), usually bearing clathrate scales and sometimes hairs.  Veins usually free or rarely reticulate (not NZ). Sori elongate on veins, superficial, borne on abaxial surface, usually away from margins but sometimes submarginal; paraphyses absent; indusia rarely absent, usually elongate with free ends or rarely very short or pouched, usually attached to one side of vein or rarely back to back on both sides. Sporangia brown or rarely orange-brown. Spores monolete, dark brown; perispores winged, cristate, echinate or reticulate, with plain, fenestrate, or reticulate areoles.

 Taxonomy

Aspleniaceae is dominated by the genus Asplenium, which includes over 700 species (PPG 1 2016). Numerous attempts have been made to subdivide the genus, with up to 20 segregates proposed, mainly on rather minor morphological characters, but only a few small groups have been widely recognised. Rather more convincing is the phylogenetic analysis of Schneider et al. (2004), who identified eight major clades based on rbcL and trnL-F spacer sequences amongst 71 species from throughout the world. This was enhanced by analysis of sequences from the same chloroplast regions for 21 taxa of indigenous New Zealand species (Perrie & Brownsey 2005a), and a further 21 taxa from Australia (Ohlsen et al. 2014). Both studies supported the clades originally identified by Schneider et al. (2004), and both showed that Asplenium was not monophyletic in either New Zealand or Australia. In fact, five of the eight clades of Schneider et al. (2004) are present in the two countries. Ohlsen et al. (2014) recognised a total of 13 clades, with some of the original eight clades further subdivided. In particular, Clade VII of Schneider et al. (2004) comprises several distinct subclades, two of which occur in New Zealand and are here considered separate clades (Clades IX and XI). The major clades in Asplenium have yet to be recognised in a formal taxonomic sense, and it is uncertain whether they correspond to any of the previously named segregates, except that most of the bird’s nest ferns fall into a clade that might correspond to Thamnopteris (C.Presl) C.Presl, while the northern hemisphere A. ruta-muraria L. together with species previously assigned to Pleurosorus occupy another. The majority of New Zealand and Australian species fall within Clade V of Schneider et al. (2004) along with, rather surprisingly, the bird’s nest ferns (Perrie & Brownsey 2005a; Ohlsen et al. 2014).

Allan (1961) accepted 12 species of Asplenium and one of Pleurosorus in New Zealand. Brownsey (1977b) revised the group and recognised 14 species and four subspecies of Asplenium. Subsequently a further four new species were described (Brownsey & Jackson 1984; Brownsey 1985; Brownsey & de Lange 1997; Perrie & Brownsey 2016), three subspecies were raised to species rank (Ogle 1988), and three introduced species or hybrids were identified (Brownsey in Webb et al. 1988; Heenan et al. 2004; Perrie et al. 2005). A total of 21 indigenous species and three introduced species or named hybrids is accepted here, almost doubling the number in Allan’s Flora.

In addition, Brownsey (1977a) recognised 19 different hybrids that occurred naturally in the New Zealand flora, a number that has since doubled to 37 combinations (see Hybrid combinations, Table 1). All produce abnormally formed or aborted spores and are thought to be effectively sterile. Hybrids between species of Asplenium account for more than half the total number of hybrid fern combinations recorded in New Zealand (Breitwieser et al. 2012), but despite these 37 different combinations, five indigenous species (A. flabellifolium, A. pauperequitum, A. polyodon, A. subglandulosum and A. trichomanes) are not known to hybridise with any other species in New Zealand. The species that do hybridise are now known to belong to Clade V of Ohlsen et al. (2014), whereas those that do not hybridise belong to Clades III, VI, IX, and XI, reinforcing the view that the eight groupings have real phylogenetic significance.

Brownsey (1977b) showed that polyploidy had been of considerable importance in the evolution of Asplenium in New Zealand, as in other parts of the world (Kramer & Viane 1990). There are no diploids in New Zealand, and all taxa are either tetraploid (11), hexaploid (2), or octoploid (10); A. trichomanes has both tetraploid and hexaploid cytotypes, and A. flabellifolium both hexaploid and octoploid cytotypes. Evidence from morphology (Brownsey 1977b, Brownsey 1977a) and DNA sequencing (Perrie & Brownsey 2005b; Shepherd et al. 2008) strongly suggests that seven octoploid species have arisen by allopolyploidy and one by autopolyploidy, in each case with at least one of the tetraploid parents still extant in New Zealand. Some have originated more than once from the same parent species (Perrie et al. 2010).

New Zealand indigenous species are assigned to the following Clades of Ohlsen et al. (2014; also see Schneider et al. 2004; Perrie & Brownsey 2005a):

Clade III: A. subglandulosum (1 species).

Clade V:  A. appendiculatum, A. bulbiferum, A. chathamense, A. cimmeriorum, A. decurrens, A. flaccidum, A. gracillimum, A. hookerianum, A. lamprophyllum, A. lepidotum, A. lyallii, A. oblongifolium, A. obtusatum, A. richardii, A. scleroprium, A. shuttleworthianum (16 species).

Clade VI: A. polyodon (1 species).

Clade IX: A. flabellifolium, A. pauperequitum (2 species).

Clade XI: A. trichomanes (1 species)

 Key
1Laminae undivided2
Laminae 1-pinnatifid or more divided3
2Laminae usually <120 mm long; lamina bases cuneate; sori attached on one side of a vein (very rarely, plants of oblongifolium will also key here, but can be distinguished by their hair-like scales)lepidotum
Laminae usually >120 mm long; lamina bases with two expanded lobes clasping the stipe; sori attached on both sides of a veinscolopendrium
3Laminae densely covered in glandular or non-glandular hairssubglandulosum
Laminae often scaly but never hairy4
4Stipes and rachises dark brown throughout except for the extreme distal tip5
Stipes and rachises green in at least the distal half8
5Primary pinnae in 1–5 pairs, with a broad undivided apical segmentpauperequitum
Primary pinnae in 5 or more pairs, with a small pinnate or pinnatifid apical segment6
6Laminae at least 2-pinnateaethiopicum
Laminae 1-pinnate; pinnae often toothed but not deeply divided7
7Laminae <20 mm wide; abaxial and adaxial surfaces of similar colour; pinna margins entire or shallowly crenate or serratetrichomanes
Laminae >40 mm wide; abaxial surface paler green than adaxial surface; pinna margins doubly and often deeply serratepolyodon
8Laminae 1-pinnate; primary pinna margins toothed but not divided more than halfway to the costa9
Lamina 1-pinnate-pinnatifd or more divided; at least one pair of primary pinnae lobed or divided more than halfway to the costa16
9Longest primary pinnae >10 times as long as broadflaccidum subsp. flaccidum
Longest primary pinnae <10 times as long as broad10
10Primary pinnae flabellate, about as long as broad; rachises extended distally and rooting at tipsflabellifolium
Primary pinnae oblong, narrowly elliptic or narrowly ovate, at least twice as long as broad; rachises not extended distally or rooting at tips11
11Margins of primary pinnae prominently and regularly toothed; sori almost reaching margins at sinusesscleroprium
Margins of primary pinnae entire or shallowly toothed; sori not reaching margins12
12Scales on stipe and rachis very narrow, with long hair-like apices; pinna apices acuminate to acute or rarely obtuse; perispores reticulateoblongifolium
Scales on stipe and rachis ovate or narrowly ovate, lacking long hair-like apices; pinna apices acute to obtuse or rounded; perispores winged or ridged but not reticulate13
13Adaxial surfaces of pinnae bearing abundant scales; plants growing on base-rich soils in inland areas14
Adaxial surfaces of pinnae lacking scales except sometimes on the costae; plants of coastal habitats growing in immediate vicinity of salt spray15
14Terminal pinna undivided or with a proximal pinnatifid lobe, incised no more than primary pinnae; spores 37–42 μm long, 23–28 μm wide*lepidotum
Terminal pinna pinnatifid, or more deeply incised than the distal margins of the primary pinnae; spores 40–54 μm long, 27–35 μm wide*lyallii
15Scales on stipe and rachis narrowly ovate, with short filiform apices; laminae 23–370 (470) mm long, 15–160 (210) mm wide; spores 45–52 μm long, 29–33 μm wide*; plants growing from Kermadec Islands to north Taranakidecurrens
Scales on stipe and rachis ovate, with very short filiform apices; laminae 27–540 mm long, 23–290 mm wide; spores 40–43 μm long, 24–27 μm wide*; plants growing from Kapiti Island to the subantarctic islandsobtusatum
16Laminae bearing bulbils on adaxial surface17
Laminae lacking bubils19
17Primary pinnae dimorphic, the fertile narrower and more divided than the sterile, occurring distally; spores aborted×lucrosum
Primary pinnae not dimorphic; spores normal18
18Laminae often bearing abundant bulbils; stipe scales ovate or broadly ovate, lacking filiform apices; spores 34–37 μm long, 23–26 μm wide*bulbiferum
Laminae usually bearing only scattered bulbils; stipe scales ovate or narrowly ovate, with filiform apices; spores 41–48 μm long, 28–32 μm wide*gracillimum
19Rhizomes short-creeping20
Rhizomes erect21
20Laminae glossy green on adaxial surface, 140–590 mm long; indusia 2–10 mm long; free margins of indusia entirelamprophyllum
Laminae dull green on adaxial surface, 10–78 mm long; indusia 1.5–3.5 mm long; free margins of indusia sometimes irregularly incisedcimmeriorum
21Basal acroscopic secondary pinna on each primary pinna much longer and more divided than the others22
Secondary pinnae on each primary pinna all about the same size, or decreasing gradually in size and division towards the distal end23
22Fronds firm and upright; spores 40–49 μm long, 26–33 μm wide*; plants of coastal rocks and cliffs, or low epiphytes on Metrosideros, in northern North Island and Kermadec Islandsflaccidum subsp.haurakiense
Fronds limp and pendulous; spores 35–46 μm long, 21–30 μm wide*; epiphytic plants of forest throughout New Zealandflaccidum subsp. flaccidum
23Sori away from pinna margins24
Sori submarginal27
24Indusia 3–14 mm long; laminae never more than 2-pinnatelyallii
Indusia 1–4 mm long; laminae often more than 2-pinnate25
25Laminae with 3–18 pairs of pinnae; secondary pinnae with long slender stalkshookerianum
Laminae with 6–40 pairs of pinnae; secondary pinnae sessile or with short, broad stalks26
26Stipe scales ovate or broadly ovate, lacking filiform apices; spores 34–37 μm long, 23–26 μm wide*bulbiferum
Stipe scales ovate or narrowly ovate with filiform apices; spores 41–48 μm long, 28–32 μm wide*gracillimum
27Laminae 1-pinnate-pinnatifid28
Laminae at least 2-pinnate29
28Secondary segments on each primary pinna all linear and about equal in sizeflaccidum subsp. flaccidum
Secondary segments on each primary pinna decreasing in size and/or division towards its distal endappendiculatum
29Ultimate lamina segments slightly expanded around the sori; plants confined to Kermadec Islandsshuttleworthianum
Ultimate lamina segments not expanded around the sori; plants not occurring on the Kermadec Islands30
30Ultimate lamina segments usually <1mm wide; indusia 1–4 mm long31
Ultimate lamina segments usually >1 mm wide; indusia 2–10 mm long32
31Primary pinnae flattened in one plane; ultimate lamina segments 0.3–0.5 mm wide; spores 31–37 µm long, 23–27 µm wide*hookerianum
Primary pinnae not flattened in one plane; ultimate lamina segments 0.5–1.0 mm wide; spores 44–49 µm long, 32–36 µm wide*richardii
32Plants confined to coastal areas on Chatham Islandschathamense
Plants of main islands of New Zealandappendiculatum

* Spore measurements are the range of mean values for sampled individuals.

 Distribution

A genus of around 700 species, subcosmopolitan in tropical, temperate, and subpolar regions of the world (Kramer & Viane 1990); 57 indigenous species in temperate South America (Zuloaga et al. 2008), c. 32 in southern Africa (Crouch et al. 2011), 90 in China (Lin & Viane 2013), 32 in Australia (Brownsey 1998) and c. 60 in the Pacific; 23 species in New Zealand; 10 endemic, 11 indigenous, two naturalised or casual, and one casual hybrid.

 Biostatus
Indigenous (Non-endemic)
Number of species and named hybrids in New Zealand within Asplenium L.
CategoryNumber
Indigenous (Endemic)10
Indigenous (Non-endemic)11
Exotic: Fully Naturalised2
Exotic: Casual1
Total24
 Hybridisation

Hybridism is widespread in Asplenium, with 37 different combinations listed here, based on specimens that can be identified with reasonable certainty (Table 1). In addition there is one casual hybrid, A. ×lucrosum, (Perrie et al. 2005). Plants of hybrid origin can be identified by their abnormally formed spores. Determining parentage is much more difficult and depends not only on morphology but also on field observations of what species were growing in the immediate vicinity of the putative hybrid. Even then it is virtually impossible to determine with certainty the parentage of any particular specimen.   

Brownsey (1977a) listed 19 different combinations. Additional combinations have been identified subsequently as new taxa have been described (Brownsey 1983, 1985; Brownsey & de Lange 1997; Perrie & Brownsey 2004; Perrie & Brownsey 2016) and as detailed lists of taxa have been compiled for specific areas, especially offshore islands (de Lange et al. 2011; de Lange 2015). A further eight combinations are listed here for the first time. Representative voucher specimens in AK, CHR and WELT are documented for each combination.

The taxon that hybridises most frequently is A. flaccidum subsp. flaccidum, with 11 combinations, followed by A. bulbiferum and A. gracillimum with eight combinations each. By contrast, there are five indigenous species (A. flabellifolium, A. pauperequitum, A. polyodon, A. subglandulosum and A. trichomanes) that are not known to hybridise with any other species in New Zealand and that appear to be phylogenetically distinct from those that do (see Taxonomy under Asplenium).

Asplenium hybrid combinations recorded in New Zealand.
Hybrid combinationRecorded byRepresentative specimens
Asplenium appendiculatum subsp. appendiculatum

 

×bulbiferum

not previously recorded

AK 210852-3

WELT P011407

  

×flaccidum subsp. flaccidum

Brownsey 1977b

AK 159295

CHR 250240

WELT P016224

 

×gracillimum

Brownsey 1983

AK 180698

CHR 446188

WELT P021336

 

×hookerianum

Brownsey 1977b

AK 126904

CHR 222410

WELT P016237

 

×lepidotum

[or possibly lepidotum × lyallii]

Perrie & Brownsey 2016

AK 30344-5

 

×lyallii

Brownsey 1977b

CHR 619027

WELT P016229

 

×richardii

Brownsey 1977b

CHR 633317

WELT P001982-3

Asplenium appendiculatum subsp. maritimum

 

×flaccidum subsp. flaccidum

Brownsey 1977b

AK 232178

CHR 308956

WELT P016227

 

×gracillimum

not previously recorded

WELT P021334

Asplenium bulbiferum

 

×cimmeriorum

Brownsey & de Lange 1997

AK 252567

CHR 418942

WELT P020244

 

×flaccidum subsp. flaccidum

Brownsey 1977b

AK 101042

CHR308933

WELT P005128

 

×gracillimum

not previously recorded

AK 172974, 357229

CHR 208670

WELT P022485, P021333

 

×hookerianum

Brownsey 1977b

WELT P016232

 

×lamprophyllum

Brownsey 1977b

AK 181450

CHR 290561

WELT P016236

 

×oblongifolium

Brownsey 1977b

AK 134804

CHR 478432

WELT P016235

 

×obtusatum

Brownsey 1977b

AK 211007, AK 211008

CHR 368721

WELT P004984

Asplenium chathamense

 

×flaccidum subsp. flaccidum

not previously recorded

AK 300982

WELT P022277

 

×lyallii

Brownsey 1985

AK 172941

CHR 403173

WELT P012511

 

×obtusatum

Brownsey 1985

AK 358174

CHR 436602

WELT P027547

Asplenium decurrens

 

×oblongifolium

Brownsey 1977b

AK 23036, 330845

CHR 353481

WELT P009341

 

×shuttleworthianum

Brownsey 1977b

AK 292899

CHR 326907

WELT P001967/A

Asplenium flaccidum subsp. flaccidum

 

×gracillimum

de Lange et al. 2011

AK 300999

WELT P016242

 

×hookerianum

Brownsey 1977b

CHR 586417

WELT P025514

 

×lepidotum

Perrie & Brownsey 2016

WELT P027644

 

×lyallii

de Lange et al. 2011

CHR 483251

WELT P012179

 

[AK 300982 cited by de Lange et al. (2011) from the Chatham Islands is not this hybrid but A. chathamense × flaccidum]

 

×oblongifolium

Brownsey 1977b

AK 185480

CHR 219816

WELT P016238

 

×obtusatum

Brownsey 1977b

CHR 362100

WELT P017879

 

×scleroprium

Brownsey 1977b

AK 170081

CHR 359220

WELT P016230

Asplenium flaccidum subsp. haurakiense

 

×decurrens

not previously recorded

AK 161183-4

AK 242181

WELT P011810

 

×oblongifolium

Brownsey 1977b

AK 171136

CHR 308963

WELT P012487

Asplenium flaccidum

 

×shuttleworthianum

not previously recorded

AK 242168

CHR 418609

Asplenium gracillimum

 

×hookerianum

Brownsey 1977

AK 209298

CHR 226519

WELT P016231

 

×lyallii

de Lange et al. 2011

Brownsey 1977b

AK 296136

CHR 195055

WELT P025550

 

×obtusatum

not previously recorded

WELT P021295

 

×richardii

not previously recorded

WELT P021335

Asplenium hookerianum

 

×oblongifolium

Perrie & Brownsey 2004

WELT P020550

Asplenium lyallii

 

×obtusatum

Brownsey 1977b

AK 115021

CHR 308949

WELT P025243

Named hybrids:

Asplenium appendiculatum subsp. appendiculatum × richardii

= Asplenium ×canterburiense J.B.Armstr., Trans. & Proc. New Zealand Inst. 14: 361 (1882)

Asplenium bulbiferum var. canterburiense (J.B.Armstr.) C.Chr., Index Fil. 104 (1905)

Holotype: Mount Arrowsmith, 4000 ft, J.F. Armstrong, March 1869, CHR 633317!

Brownsey (1977b) examined the holotype of Asplenium canterburiense and concluded that it was probably a hybrid between A. terrestre (= A. appendiculatum) and A. richardii, based on its morphology and aborted spores.

Asplenium bulbiferum × obtusatum

= Asplenium bulbiferum var. integra Kirk, Trans. & Proc. New Zealand Inst. 17: 232 (1885)

Lectotype (selected by Brownsey & Perrie 2017): Ulva [Island, Stewart Island], 14.12.1883, Herb. T. Kirk, WELT P004984 (on two sheets)!

Kirk (1885) described Asplenium bulbiferum var. integra from Ulva Island, Stewart Island. Syntype material from Kirk’s visit to Ulva in 1883 is in AK and WELT. All four sheets have fronds with aborted spores – probably derived from A. bulbiferum and A. obtusatum, but possibly involving A. gracillimum or A. scleroprium.

Cultivars: A number of cultivars of Asplenium are sold in the horticultural trade. Asplenium ×lucrosum is widely cultivated and usually sold as "Asplenium bulbiferum". Another common cultivar, "Maori Princess", may be a hybrid between A. bulbiferum and A. oblongifolium or A. obtusatum; it is possible that both combinations are present within "Maori Princess" as it is variable.

Incertae sedis

Asplenium bulbiferum var. decomposita Kirk, Trans. & Proc. New Zealand Inst. 17: 232 (1885)

Type: Ulva Island, T. Kirk [not located in AK, CHR, K, MEL, WELT]

Asplenium bulbiferum var. pseudolucidum Kirk, Trans. & Proc. New Zealand Inst. 17: 232 (1885)

Type: Ulva Island, T. Kirk [not located in AK, CHR, K, MEL, WELT]

Asplenium obtusatum var. pseudofalcatum Kirk, Trans. & Proc. New Zealand Inst. 17: 231 (1885)

Type: Mason Bay, Stewart Island, T. Kirk [not located in AK, CHR, K, MEL, WELT]

Asplenium tremulum Hombr. in Hombron & Jacquinot, Voy. Pôle Sud, Bot., Atlas t. 3b, f. Δ (1843)

Asplenium bulbiferum var. tremulum (Hombr.) Domin, Biblioth. Bot. 20(85): 104 (1913)

Type: said to be from "Isles Mascaraignes, Tavaï, N’elle Zél’de" [not located in P]

 Cytology

The base chromosome number in Asplenium is x = 36 (Kramer & Viane 1990; Smith et al. 2006).

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