| Nerine | |
|---|---|
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Asparagales |
| Family: | Amaryllidaceae |
| Subfamily: | Amaryllidoideae |
| Subtribe: | Strumariinae |
| Genus: | Nerine Herb.,nom. cons.[1][2] |
| Type species | |
| Nerine sarniensis (L.) Herb. | |
| Species | |
| Synonyms[3] | |
Nerine/nɪˈraɪniː/[4] (nerines,Guernsey lily,Jersey lily,spider lily) is agenus offlowering plants belonging to thefamilyAmaryllidaceae, subfamilyAmaryllidoideae. They arebulbousperennials, someevergreen, associated with rocky and arid habitats. They bear spherical umbels of lily-like flowers in shades from white through pink to crimson. In the case ofdeciduous species, the flowers may appear on naked stems before the leaves develop.Native to South Africa, there are about 20–30species in the genus. Though described as lilies, they are not significantly related to the true lilies (Liliaceae), but more closely resemble their relatives,Amaryllis andLycoris. The genus was established by theRevd.William Herbert in 1820.
Nerines have been widely cultivated and muchhybridized worldwide, especiallyNerine bowdenii,N. masoniorum,N. sarniensis andN. undulata (previously known asN. flexuosa). The hybridcultivar 'Zeal Giant' has gained theRoyal Horticultural Society'sAward of Garden Merit. Most of the other 20 species are rarely cultivated and very little is known regarding their biology. Many species are threatened with extinction due to the loss or degradation of their habitat.
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Species ofNerine areherbaceousperennial bulbousflowering plants. In the case ofdeciduous species, theinflorescence may appear on naked stems before theleaves develop (hysteranthy), otherwise they appear together with theflowers (synanthy) or afterwards.[5][6][7]
The bulbs may have a short neck, but this is absent in other species. The leaves arefiliform (threadlike) (as inN. filifolia;Figure 1D) to linear and flat and strap-shaped (as inN. humilis;Figure 2C). Their flowers, which are few, are borne in sphericalumbels on a solid leafless stem (scape or peduncle). The stem may be slender or robust, and rarely minutelypuberulous (hairy), with twolanceolate (lance shaped)spathe-valves (spathal bracts) surrounding the inflorescence. Thepedicels (flower stalks) may be glabrous (hairy) or smooth, a feature used indifferentiating species.
Individual flowers are lily-like, generally with aperianth that iszygomorphic (with one plane of symmetry) but may beactinomorphic (radially symmetrical or "regular"). Each flower is flared, usually with a short extended or recurved perianth tube, consisting of six narrow white, pink or redtepals (perianth segments) joined at the base to form the tube. The free parts of the tepals are generally narrowlyoblanceolate (wider near tip) andundulate (wavy) withcrisped (curly) margins.[6][7]
The sixstamens may bedeclinate (curvy) or erect, are unequal and are inserted into the base of the tepals, and areconnate (fused) at their bases, frequently protruding from the flower. The stamen filaments are thin and filiform, but may beappendiculate (bearing appendages) at their base, a feature that is also important indifferentiating species. Theiranthers are versatile (swinging freely) and oblong and attach to the filament at the back (dorsifixed).[6][7] Thepollen isbisulcate (two grooves).[8]
Theinferior ovary issubglobose (slightly flattened sphere) and trilocular (three-lobed or threelocules), with one to fourovules in each loculus. Thestyle is filiform, straight or declinate and has an obscurelytricuspidate (three tipped)stigmatose apex.[6][7] Thefruit is a subglobose dry loculicidaldehiscentcapsule, that produces between one and a fewseeds per loculus that areglobose to ovoid, red-green and oftenviviparous (begin to develop before separating).[6][7][9]
Chromosome number: 11 (2n=22),[10][11][12][7] but rarely 2n=24 ortriploids.[13][14]
The first description was published in 1635 by French botanistJacques-Philippe Cornut, who examined 'Narcissus Iaponicus rutilo flore' (N. sarniensis), a plant he found in the garden of the Paris nurseryman Jean Morin in October 1634, assuming it was originally from Japan.[15] In 1680 Scottish botanistRobert Morison gave an account of 'Lilio-Narcissus Japonicus rutilo flore' that was said to have been washed ashore when a Dutch or English vessel coming from Japan was wrecked off Guernsey. In 1725James Douglas published an account in hisA Description of the Guernsay Lilly,[16] as it was known then. Douglas gave it the nameLilio-Narcissus Sarniensis Autumno florens.[17][a] Linnaeus called thisAmaryllis sarniensis in 1753, after Douglas' usage, one of nine species he assigned to this genus.[14][18]
The earliest published name for the genus wasImhofia, given byLorenz Heister in 1755.[19] The later nameNerine, published byWilliam Herbert in 1820, was widely used, resulting in a decision toconserve the nameNerine and reject the nameImhofia (nom. rej.). Herbert was unaware of Heister's work initially in 1820, but noting that Heister had not defined it and it had not been adopted, transferred the name toAmaryllis marginata, retainingNerine forN. sarniensis and renamingA. marginataImhofia marginata (nowBrunsvigia marginata).[20]
Herbert's main role was in untangling a number of distinct genera that Linnaeus had included underAmaryllis.[21][2] Although in Herbert's description ofNerine rosea there, he attempted to distinguish it fromN. sarniensis, the former is now accepted as a synonym of the latter, the accepted name.[22] When Herbert chose the name of these nymphs for the first species of the genus,Nerine sarniensis, he alluded to the story of how this South African species arrived on the island ofGuernsey in theEnglish Channel. It is said that a ship carrying boxes of the bulbs of this species destined for theNetherlands was shipwrecked on Guernsey. The boxes of bulbs were washed up on the island and the bulbs became established and multiplied around the coast.[23] Herbert eventually recognised nine species. At that timeAmaryllis (and henceNerine) were placed in the family Amaryllideae, following the classification ofde Candolle (1813).[24] Herbert's main interests were in the taxonomy of amaryllids, publishing a monograph on this in 1837,[25] considering Amaryllideae as one of seven suborders of Amaryllidaceae. He then further subdivided this suborder into groups, placing Nerine and Amaryllis together with twelve other genera into the Amaryllidiformes.[26] In his extensive treatment of Nerine he divided the nine species he recognised into two sections,Regulares andDistortae, of which onlyN. humilis andN. undulata are still in use. He had also begun a breeding program and described sevenhybrids he had raised.[27] His enthusiasm for the genus is evident in that he chose to illustrate the front of the book with one of his hybrids,N. mitchamiae (seeillustration).[28]
New species continued to be described so that by the timeTraub published his monograph in 1967, he identified 30 species.[13] Other authors, including Norris (1974)[29] and Duncan (2002),[30][12] have identified 31 and 25 species respectively. At one stage 53 species were described.[31] Snijman and Linder (1996), who used acladistic analysis of 33 characteristics and chromosome number, reduced this to 23, assigning many of these species tovarietal status. They consideredNerine to be characterised byzygomorphic flowers with attenuated tepals and crisped margins.[32]
In theAPG IV system (2016),[33] the genusNerine is placed in thesubfamilyAmaryllidoideae of a broadly definedfamilyAmaryllidaceae. Within the subfamily,Nerine is placed in the Southern AfricantribeAmaryllideae.[34] Thephylogenetic relationships of the Amaryllideae have been investigated throughmolecular analysis of DNA combined withmorphological data. Thiscladistic analysis has demonstrated thatNerine belongs to amonophyletic group formingsubtribeStrumariinae. The members of thisclade all originate from South Africa and often have prostrate leaves, fused stamens forming a tube towards the base of the flower, dehiscent fruit, and seeds with a well developedseed coat andchlorophyll. Within the Strumariinae,Nerine is most closely related toBrunsvigia Heist., Namaquanula D. & U. Müll.-Doblies andHessea Herb.[14][35]
The genera of Strumariinae are related as in thiscladogram, with number of species in each genus in (parentheses):[35]
| Strumariinae |
| |||||||||||||||||||||||||||||||||
Attempts to generate an infrageneric classification (such as those of Traub's four sections and Norris' twelve groups) based onmorphological characteristics alone relied on the presence of appendages to the bases of thestamen filaments, the presence of hairs on theovary,scape andpedicels, together with the shape and arrangement ofperianth segments.[14] Traub divided the genus into four subgenericsections,Nerine,Laticomae,Bowdeniae andAppendiculatae. For instance the six taxa ofLaticomae were grouped on the basis of filaments that were not distinctly appendiculate or otherwise modified at the base and scapes that were relatively short and stout.
Much of the modern understanding of the genus comes from the work ofGraham Duncan and colleagues atSANBI, Kirstenbosch. In 2002 Duncan grouped the species ofNerine by growth cycle, with three distinct patterns.[30][30]Nerine species can be eitherevergreen ordeciduous, the deciduous species either growing during the winter or the summer. Zonnefeld and Duncan (2006)[14] examined the total amount ofnuclearDNA byflow cytometry in 81accessions from 23 species. When the species were arranged by DNA content, five groupings (A–E) were apparent, that correlated with growth cycle and leaf width, but only two of the other characteristics (filament appendages and hairy pedicels). Traub's sections were not confirmed, although a slightly better agreement was found with Norris' groups. Leaf width fell into two main groups, narrow (1–4 mm) or broad (6–37 mm). When taken together these characteristics confirm Duncan's original three groups based on growth cycle alone.
The first of these is the largest of these groups, corresponding to DNA groups A, B and C, with 13 species, and contains narrow-leafed evergreen nerines that retain their leaves throughout the summer and winter. They contain the lowest amount of DNA per nucleus. The second group corresponds to DNA group D with four broad-leafed deciduous winter growing species. They contain an intermediate amount of DNA. A third group (DNA group E) has six broad-leafed summer growing deciduous species that have no leaves in the winter. They contain the highest amount of DNA.[14] The two broad-leaved groups are also distinguished by the absence of filamentous appendages and glabrous pedicels, although two of the species have hairs on the pedicels, but these are minute or sparse.
The first group (the evergreens) can then be considered to have three subgroups corresponding to DNA groups A, B and C but also by other characteristics.N. marincowitzii is an outlier being summer growing but narrow-leafed. The other outlier isN. pusilla which is narrow-leafed despite being summer growing.N. duparquetiana has at times been considered to be a synonym ofN. laticoma but was restored to species status here.N. huttoniae is another species whose status is disputed, but here is treated (as Traub did) as a subspecies ofN. laticoma, a status subsequently confirmed.[36] Two species of doubtful status were not accessed,N. transvaalensis andN. hesseoides.[14]
Based on morphology, geography and DNA content they concluded that there were in fact 23 species, in contrast to the large number ofsubspecies considered by Traub.[37][14]
As of 2016[update], theWorld Checklist of Selected Plant Families (WCLSPF) recognises 24 species[38] andThe Plant List (TPL), 25[39] (for explanation of the discrepancy, see Notes). Species accepted by the WCLSPF and arrangedsensu Zonnefeld & DuncanTable 2[14] are:[b]
Some known hybrids, along with the parent species, are the following:
SomeNerine species have been used to produce a hybrid with members of the genusAmaryllis, which are included in the hybrid genus (nothogenus) × Amarine. One of these hybrids is × Amarine tubergeniiSealy, which comes from a cross betweenAmaryllis belladonna andNerine bowdenii.[38]
The genus name given to it by Herbert in 1820 derives from theNereids (sea-nymphs) ofGreek mythology that protected sailors and their ships. Herbert combinedMorison's account of the plant being washed ashore from a shipwreck with Renaissance poetry, alluding to the rescue ofVasco da Gama’s ship by a Nereid in the epic poem ofCamões,Os Lusiadas.[46] Although bearing the name "lily" in thevernacular,Nerine is only distantly related to the true lilies (Lilium) of the lily family,Liliaceae,sensu stricto. Instead they are one of many genera placed in the amaryllid lily family, Amaryllidaceae, such as the closely relatedAmaryllis, andLycoris. These were once part of the much larger construction of Liliaceaesensu lato. The name "spider lily" is shared by a number of different genera within Amaryllidaceae. For instance,Lycoris aurea may be sold under its earlier synonym,Nerine aurea.[40]
Nerine are native toSouthern Africa, theirdistribution range being from theCape Peninsula in the south toBotswana,Eswatini,Lesotho,Namibia to the northwest and northeast ofSouth Africa, occupying all nine provinces of South Africa. (see distribution maps in Zonneveld & Duncan, 2006).[14][23] They prefer rocky, arid andmesic habitats, and most species are found in thesummer rainfall region.[32]
Nerine species form three distinct growth patterns, namely winter-growing, summer-growing and evergreen species.[23] While the flowers are generally pink, a red colour is an adaptation to apollinator, the butterflyAeropetes tulbaghia.[7]
SomeNerine species from Eastern Cape Province are naturally rare, but they are not considered to be in immediate danger of extinction. These include the winter-growing speciesN. pudica that inhabits inaccessible locations in theDu Toitskloof and Sonderend mountains, and the summer-growingN. marincowitzii that originates from the semi-aridKaroo region.
A number of evergreen nerine species from areas of South Africa that have summer rain are in danger due to the loss or degradation of their habitat and at least two or three of them are on the verge of extinction.Nerine masoniorum is probably the most critically threatened and it may even have become extinct as the area occupied by the only surviving colony has been used for the construction of housing.[47] Another species that is seriously threatened isN. gibsonii from Eastern Cape Province as the grasslands that it grows in have been seriously damaged by overgrazing anderosion resulting from the construction of paths and roads. In addition, this species rarely produces seeds as grazing cattle eat the flowers as soon as they appear.[48]
Various measures have been taken to relieve the threat of extinction from these species. One of these measures, thanks to their ease of cultivation, is theex situ conservation of a number of populations ofN. filamentosa,N. gibsonii,N. gracilis,N. huttoniae andN. masoniorum in theKirstenbosch botanical garden.[49] Another measure, this time relating toin situ cultivation is the official protection of some species in nature reserves, such as has happened forN. platypetala in the south ofMpumalanga.[50]
In Guernsey, the national flower isNerine sarniensis, and the island collection of nerines is seeking recognition byNational Council for the Conservation of Plants and Gardens as a national collection.[51]
Breeding and hybridisation of Nerine began as early as the beginning of the nineteenth century with the work ofWilliam Herbert. A number of the species of this genus are cultivated asornamentals, such asN. sarniensis,N. undulata (N. flexuosa) andNerine bowdenii.[12]N. sarniensis is, probably, the best known species of the genus and it has been cultivated in Europe since the beginning of the 17th century.N. bowdenii was introduced to England at the end of the 19th century and used as an ornamental since the first decade of the 20th century.[52] Along withNerine bowdenii they have been extensively used in plant breeding programmes that have produced the majority of the commercially available hybrids.[11] The hybridcultivar 'Zeal Giant' has gained theRoyal Horticultural Society'sAward of Garden Merit.[53]
The bulbs ofNerine species need a minimum of two years growth and development in order to produce their first flowers. The largest bulbs can give rise to two stems or more if they have been grown under suitable conditions. They are used ascut flowers as they can survive up to 14 days in a vase with water without showing any staining.[12]
Nerine species and hybrids with their colourful long-lasting blooms are grown commercially for the cut-flower industry and sale of ornamental bulbs.[14][31]
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