Narcissus (plant)
| Floral formula | |
| Br ✶ ☿ P3+3+Corona A3+3 G(3) Bracteate, Actinomorphic, Bisexual Perianth: 6 tepals in 2 whorls of 3 Stamens: 2 whorls of 3 Ovary: Superior – 3 fused carpels |
| Narcissus Temporal range: Late Oligocene – Recent | |
|---|---|
 | |
| Narcissus poeticus | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Asparagales |
| Family: | Amaryllidaceae |
| Subfamily: | Amaryllidoideae |
| Tribe: | Narcisseae |
| Genus: | Narcissus L.[1] |
| Type species | |
| Narcissus poeticus | |
| Subgenera | |
| Synonyms | |
|
List
| |
Narcissus is a genus of predominantly spring flowering perennial plants of the amaryllis family, Amaryllidaceae. Various common names including daffodil,[Note 1] narcissus (plural narcissi), and jonquil, are used to describe some or all members of the genus.
Narcissus has conspicuous flowers with six petal-like tepals surmounted by a cup- or trumpet-shaped corona. The flowers are generally white and yellow (also orange or pink in garden varieties), with either uniform or contrasting coloured tepals and corona.
Narcissi were well known in ancient civilisation, both medicinally and botanically, but were formally described by Linnaeus in his Species Plantarum (1753). The genus is generally considered to have about ten sections with approximately 70–80 species; the Plants of the World Online database currently accepts 76 species and 93 named hybrids.[3] The number of species has varied, depending on how they are classified, due to similarity between species and hybridisation.
The genus arose some time in the Late Oligocene to Early Miocene epochs, in the Iberian Peninsula and adjacent areas of southwest Europe. The exact origin of the name Narcissus is unknown, but it is often linked to a Greek word (ancient Greek ναρκῶ narkō, "to make numb") and the myth of the youth of that name who fell in love with his own reflection. The English word "daffodil" appears to be derived from "asphodel", with which it was commonly compared.[4]
The species are native to meadows and woods in southern Europe and North Africa with a centre of diversity in the Western Mediterranean. Both wild and cultivated plants have naturalised widely, and were introduced into the Far East prior to the tenth century. Narcissi tend to be long-lived bulbs, which propagate by division, but are also insect-pollinated. Known pests, diseases and disorders include viruses, fungi, the larvae of flies, mites and nematodes. Some Narcissus species have become extinct, while others are threatened by increasing urbanisation and tourism.
Historical accounts suggest narcissi have been cultivated from the earliest times, but became increasingly popular in Europe after the 16th century and by the late 19th century were an important commercial crop centred primarily in the Netherlands. Today, narcissi are popular as cut flowers and as ornamental plants. The long history of breeding has resulted in thousands of different cultivars. For horticultural purposes, narcissi are classified into divisions, covering a wide range of shapes and colours. Narcissi produce a number of different alkaloids, which provide some protection for the plant, but may be poisonous if accidentally ingested. This property has been exploited for medicinal use in traditional healing and has resulted in the production of galantamine for the treatment of Alzheimer's dementia. Narcissi are associated with a number of themes in different cultures, ranging from death to good fortune, and as symbols of spring. The daffodil is the national flower of Wales and the symbol of cancer charities in many countries. The appearance of wild flowers in spring is associated with festivals in many places.
Description
[edit]
.jpg)
_-_8.jpg)
General
[edit]Narcissus is a genus of perennial herbaceous bulbiferous geophytes, which die back after flowering to an underground storage bulb. They regrow in the following year from brown-skinned ovoid bulbs with pronounced necks, and reach heights of 5–80 centimetres (2.0–31.5 in) depending on the species. Dwarf species such as N. asturiensis have a maximum height of 5–8 centimetres (2.0–3.1 in), while Narcissus tazetta may grow as tall as 80 centimetres (31 in).[5][6]
The plants are scapose, having a single central leafless hollow flower stem (scape). Several green or blue-green, narrow, strap-shaped leaves arise from the bulb. The plant stem usually bears a solitary flower, but occasionally a cluster of flowers (umbel). The flowers, which are usually conspicuous and white or yellow, sometimes both or rarely green, consist of a perianth of three parts. Closest to the stem (proximal) is a floral tube above the ovary, then an outer ring composed of six tepals (undifferentiated sepals and petals), and a central disc to conical shaped corona. The flowers may hang down (pendant), or be erect. There are six pollen-bearing stamens surrounding a central style. The ovary is inferior (below the floral parts) consisting of three chambers (trilocular). The fruit consists of a dry capsule that splits (dehisces) releasing numerous black seeds.[6]
The bulb lies dormant after the leaves and flower stem die back and has contractile roots that pull it down further into the soil. The flower stem and leaves form in the bulb, to emerge the following season. Most species are dormant from summer to late winter, flowering in the spring, though a few species are autumn flowering.[6]
Specific
[edit]Vegetative
[edit]- Bulbs
The pale brown-skinned ovoid tunicate bulbs have a membranous tunic and a corky stem (base or basal) plate from which arise the adventitious root hairs in a ring around the edge, which grow up to 40 mm (1.6 in) in length. Above the stem plate is the storage organ consisting of bulb scales, surrounding the previous flower stalk and the terminal bud. The scales are of two types, true storage organs and the bases of the foliage leaves. These have a thicker tip and a scar from where the leaf lamina became detached. The innermost leaf scale is semicircular, only partly enveloping the flower stalk (semisheathed). (see Hanks Fig 1.3). The bulb may contain a number of branched bulb units, each with two to three true scales and two to three leaf bases. Each bulb unit has a life of about four years.[6][7]
Once the leaves die back in summer, the roots also wither. After some years, the roots shorten, pulling the bulbs deeper into the ground (contractile roots). The bulbs develop from the inside, pushing the older layers outwards which become brown and dry, forming an outer shell, the tunic or skin. Up to 60 layers have been counted in some wild species. While the plant appears dormant above the ground the flower stalk, which will start to grow in the following spring, develops within the bulb surrounded by two to three deciduous leaves and their sheaths. The flower stem lies in the axil of the second true leaf.[6]
- Stems
The single leafless plant stem or scape, appearing from early to late spring depending on the species, bears from 1 to 20 blooms.[8] Stem shape depends on the species; some are highly compressed with a visible seam, while others are rounded. The stems are upright and located at the centre of the leaves. In a few species such as N. hedraeanthus the stem is oblique. The stem is hollow in the upper portion but towards the bulb is more solid and filled with a spongy material.[9]
- Leaves
Narcissus plants have one to several basal leaves which are linear, ligulate or strap-shaped (long and narrow), sometimes channelled adaxially to semiterete, and may (pedicellate) or may not (sessile) have a petiole stalk.[10] The leaves are flat and broad to cylindrical at the base and arise from the bulb.[11] The emerging plant generally has two leaves, but the mature plant usually three, rarely four, and they are covered with a cutin-containing cuticle, giving them a waxy appearance. Leaf colour is light green to blue-green. In the mature plant, the leaves extend higher than the flower stem, but in some species, the leaves are low-hanging. The leaf base is encased in a colourless sheath. After flowering, the leaves turn yellow and die back once the seed pod (fruit) is ripe.[6]
Jonquils usually have dark green, round, rush-like leaves.[12]
Reproductive
[edit]- Inflorescence
The inflorescence is scapose, the single stem or scape bearing either a solitary flower or forming an umbel with up to 20 blooms.[8] Species bearing a solitary flower include section Bulbocodium and most of section Pseudonarcissus. Umbellate species have a fleshy racemose inflorescence (unbranched, with short floral stalks) with 2 to 15 or 20 flowers, such as N. papyraceus (see illustration, left) and N. tazetta (see Table I).[13][14] The flower arrangement on the inflorescence may be either with (pedicellate) or without (sessile) floral stalks.[9]
Prior to opening, the flower buds are enveloped and protected in a thin, dry, papery or membranous (scarious) spathe. The spathe consists of a singular bract that is ribbed, and which remains wrapped around the base of the open flower. As the bud grows, the spathe splits longitudinally.[15][16] Bracteoles are small or absent.[9][15][14][17]
- Flowers
The flowers of Narcissus are hermaphroditic (bisexual),[18] have three parts (tripartite), and are sometimes fragrant (see Fragrances).[19] The flower symmetry is actinomorphic (radial) to slightly zygomorphic (bilateral) due to declinate-ascending stamens (curving downwards, then bent up at the tip). Narcissus flowers are characterised by their, usually conspicuous, corona (trumpet).[9]
The three major floral parts (in all species except N. cavanillesii in which the corona is virtually absent - Table I: Section Tapeinanthus) are:
- (i) the proximal floral tube (hypanthium),
- (ii) the surrounding free tepals, and
- (iii) the more distal corona (paracorolla, paraperigon, paraperigonium).[20]
All three parts may be considered to be components of the perianth (perigon, perigonium). The perianth arises above the apex of the inferior ovary, its base forming the hypanthial floral tube.[20]
The floral tube is formed by fusion of the basal segments of the tepals (proximally connate). Its shape is from an inverted cone (obconic) to funnel-shaped (funneliform) or cylindrical, and is surmounted by the more distal corona. Floral tubes can range from long and narrow (in sections Apodanthi and Jonquilla) to rudimentary (N. cavanillesii).[21]
Surrounding the floral tube and corona and reflexed (bent back) from the rest of the perianth are the six spreading tepals or floral leaves, in two whorls which may be distally ascending, reflexed (folded back), or lanceolate. Like many monocotyledons, the perianth is homochlamydeous, which is undifferentiated into separate calyx (sepals) and corolla (petals), but rather has six tepals. The three outer tepal segments may be considered sepals, and the three inner segments petals. The transition point between the floral tube and the corona is marked by the insertion of the free tepals on the fused perianth.[7]
The corona, or paracorolla, is variously described as bell-shaped (funneliform, trumpet), bowl-shaped (cupular, crateriform, cup-shaped) or disc-shaped with margins that are often frilled, and is free from the stamens. Rarely is the corona a simple callose (hardened, thickened) ring. The corona is formed during floral development as a tubular outgrowth from stamens which fuse into a tubular structure, the anthers becoming reduced. At its base, the fragrances which attract pollinators are formed. All species produce nectar at the top of the ovary.[13] Coronal morphology varies from the tiny pigmented disk of N. serotinus (see Table I) or the rudimentary structure in N. cavanillesii to the elongated trumpets of section Pseudonarcissus (trumpet daffodils, Table I).[10][13][14][7]
While the perianth may point forwards, in some species such as N. cyclamineus it is folded back (reflexed, see illustration, left), while in some other species such as N. bulbocodium (Table I), it is reduced to a few barely visible pointed segments with a prominent corona.[20]
The colour of the perianth is white, yellow or bicoloured, with the exception of the night flowering N. viridiflorus, which is green. In addition, the corona of N. poeticus has a red crenulate margin (see Table I).[11] Flower diameter varies from 12 mm (N. bulbocodium) to over 125 mm (N. nobilis=N. pseudonarcissus subsp. nobilis).[21]
Flower orientation varies from pendent or deflexed (hanging down) as in N. triandrus (see illustration, left), through declinate-ascendant as in N. alpestris = N. pseudonarcissus subsp. moschatus, horizontal (patent, spreading) such as N. gaditanus or N. poeticus, erect as in N. cavanillesii, N. serotinus and N. rupicola (Table I), or intermediate between these positions (erecto-patent).[9][11][13][14][17][22][21]
The flowers of Narcissus demonstrate exceptional floral diversity and sexual polymorphism,[17] primarily by corona size and floral tube length, associated with pollinator groups (see for instance Figs. 1 and 2 in Graham and Barrett[13]). Barrett and Harder (2005) describe three separate floral patterns:
- "Daffodil" form
- "Paperwhite" form
- "Triandrus" form.[20]
The predominant patterns are the 'daffodil' and 'paperwhite' forms, while the "triandrus" form is less common. Each corresponds to a different group of pollinators (See Pollination).[17]
The "daffodil" form, which includes sections Pseudonarcissus and Bulbocodium, has a relatively short, broad or highly funnelform tube (funnel-like), which grades into an elongated corona, which is large and funnelform, forming a broad, cylindrical or trumpet-shaped perianth. Section Pseudonarcissus consists of relatively large flowers with a corolla length of around 50 mm (2.0 in), generally solitary but rarely in inflorescences of 2–4 flowers. They have wide greenish floral tubes with funnel-shaped bright yellow coronas. The six tepals sometimes differ in colour from the corona and may be cream coloured to pale yellow.[18]
The "paperwhite" form, including sections Jonquilla, Apodanthi and Narcissus, has a relatively long, narrow tube and a short, shallow, flaring corona. The flower is horizontal and fragrant.[17]
The "triandrus" form is seen in only two species, N. albimarginatus (a Moroccan endemic) and N. triandrus. It combines features of both the "daffodil" and "paperwhite" forms, with a well-developed, long, narrow tube and an extended bell-shaped corona of almost equal length. The flowers are pendent.[17]
There are six stamens in one to two rows (whorls), with the filaments separate from the corona, attached at the throat or base of the tube (epipetalous), often of two separate lengths, straight or declinate-ascending (curving downwards, then upwards). The anthers are basifixed (attached at their base).[10][7]
The ovary is inferior (below the floral parts) and trilocular (three chambered) and there is a pistil with a minutely three lobed stigma and filiform (thread like) style, which is often exserted (extending beyond the tube).[23][7]
- Fruit
The fruit consists of dehiscent loculicidal capsules (splitting between the locules) that are ellipsoid to subglobose (almost spherical) in shape and are papery to leathery in texture.[9]
- Seeds
The fruit contains numerous subglobose seeds which are round and swollen with a hard coat, sometimes with an attached elaiosome. The testa is black[10] and the pericarp dry.[14]
Most species have 12 ovules and 36 seeds, although some species such as N. bulbocodium have more, up to a maximum of 60. Seeds take five to six weeks to mature. The seeds of sections Jonquilla and Bulbocodium are wedge-shaped and matt black, while those of other sections are ovate and glossy black. A gust of wind or contact with a passing animal is sufficient to disperse the mature seeds.[citation needed]
Chromosomes
[edit]Chromosome numbers include 2n=14, 22, 26, with numerous aneuploid and polyploid derivatives. The basic chromosome number is 7, with the exception of N. tazetta, N. elegans and N. broussonetii in which it is 10 or 11; this subgenus (Hermione) was in fact characterised by this characteristic. Polyploid species include N. papyraceus (4x=22) and N. dubius (6x=50).[7]
Phytochemistry
[edit]Alkaloids
[edit]As with all Amaryllidaceae genera, Narcissus contains unique isoquinoline alkaloids. The first alkaloid to be identified was lycorine, from N. pseudonarcissus in 1877. These are considered a protective adaptation and are utilised in the classification of species. Nearly 100 alkaloids have been identified in the genus, about a third of all known Amaryllidaceae alkaloids, although not all species have been tested. Of the nine alkaloid ring types identified in the family, Narcissus species most commonly demonstrate the presence of alkaloids from within the Lycorine (lycorine, galanthine, pluviine) and Homolycorine (homolycorine, lycorenine) groups. Hemanthamine, tazettine, narciclasine, montanine and galantamine alkaloids are also represented. The alkaloid profile of any plant varies with time, location, and developmental stage.