| Phalaenopsis | |
|---|---|
 | |
| Phalaenopsis philippinensis | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Asparagales |
| Family: | Orchidaceae |
| Subfamily: | Epidendroideae |
| Tribe: | Vandeae |
| Subtribe: | Aeridinae |
| Genus: | Phalaenopsis Blume[1] |
| Type species | |
| Phalaenopsis amabilis Blume (1825) | |
| Species | |
About 70; seeList ofPhalaenopsis species | |
| Synonyms[1] | |
Phalaenopsis (/ˌfælɪˈnɒpsɪs/), also known asmoth orchids,[2] is agenus of about seventy species of plants in thefamilyOrchidaceae. Orchids in this genus aremonopodialepiphytes orlithophytes with long, coarse roots, short, leafy stems and long-lasting, flat flowers arranged in a flowering stem that often branches near the end. Orchids in this genus are native to Asia,New Guinea, and Australia, but mostly occur inIndonesia and thePhilippines.
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Orchids in the genusPhalaenopsis are monopodial epiphytic, sometimes lithophyticherbs with long, coarse roots withpneumatodes (which allow for gaseous exchange of thephotosynthetic roots),[3][4] and short leafy stems hidden by overlapping leaf bases. The leaves are usually arranged in two rows, relatively large and leathery, oblong to elliptic and sometimes succulent. A few to many, small to large, long-lasting, flat, often fragrant flowers are arranged on erect to hangingracemes orpanicles. Thesepals andpetals are free from and spread widely apart from each other. Thelateral sepals are usually larger than thedorsal sepal and the petals much wider than the sepals. Thelabellum is joined stiffly to thecolumn and has three lobes. The side lobes are erect and more or less parallel to each other and the middle lobe sometimes has a pair of appendages or antennae.[2][5][6][7]
Unlike most other angiosperms, the development of theovules is triggered bypollination. Therefore a temporal mismatch of male and femalegametes exists (i.e. the male structures are ready but the female structures have not yet been fully developed). In orchids,fertilisation occurs within days or months after the pollination event. After pollination occurs, thestigmatic cavity is often closed through swelling of thecolumn. As a result, thepollinia are completely enclosed. The pollen germinates after enclosure and tubes are produced. InPhalaenopsis aphrodite, pollen tubes entered the ovary within 3 days after pollination. Within 15 days, pollen tubes evenly spread throughout theplacental cavities. Within 60 days after the pollination event, 30.6% of the tips of the pollen tubes started to enter the micropyles (i.e. entry points) of the ovules. Finally, 65 to 70 days after the pollination event, fertilisation occurred.[8]
Phalaenopsis are unique in that in some species of the subgenusPolychilos, the flowers turn into green leaves after pollination. As in many other plants, the petals of the orchid flowers serve to attract pollinating insects and protect essential organs. Following pollination, petals usually will undergosenescence (i.e. wilt and disintegrate) because it is metabolically expensive to maintain them. However, in manyPhalaenopsis species, such asP. violacea, the petals and sepals find new uses following pollination, thus escapingprogrammed cell death. In producingchloroplasts, they turn green, become fleshy, and start to photosynthesize, as leaves do.[9]
Floral fragrance has been analysed for several species. The fragrance ofPhalaenopsis bellina has been shown to be composed of about 79 compounds, primarily of theterpenoid class. It was most intense in the morning.[10]
InPhalaenopsis,phenylpropanoid enzymes are enhanced in the process of plantacclimatisation at different levels of photosynthetic photon flux.[11]
The genusPhalaenopsis was first formally described in 1825 byCarl Ludwig Blume and the description was published inBijdragen tot de flora van Nederlandsch Indië.[1][12] The namePhalaenopsis is derived from theAncient Greek wordφαλαινα (phalaina) meaning 'a kind of moth'[13]: 535 with thesuffix-opsis meaning 'having the appearance of' or 'like'.[13]: 483 [14]
The genus name is abbreviatedPhal. horticulturally.[15]
The large monophyletic genusPhalaenopsis is divided into several sub-units. They are either regarded as subgenera or as sections. Not all of them are monophyletic.[citation needed]The subgenusPolychilos is monophyletic and it is divided into two subclades. The subgenusPhalaenopsis is paraphyletic under its current definition. Likewise the evidence shows that the subgeneraAphyllae andParishianae, as currently defined, are not monophyletic. The position of the monotypic subgenusProboscidioides, which only consists ofPhalaenopsis lowii, suggests a close relationship with the subgenusAphyllae.[16]
The followingphylogenetic tree is a simplified tree to show the general placement of the main infrageneric groups. It is meant to give an overview, despite the contended monophyly of some of the respective groups.[17][18][19][20]
| Phalaenopsis |
| 2 pollinia clade 4 pollinia clade | |||||||||||||||||||||||||||
The former genusOrnithochilus was merged withPhalaenopsis and is considered by some to be a subgenus. Its members have distinctly 4-lobed, fringed labella with a short, curved spur situated near the middle of the lip as opposed to the base.Ornithochilus formerly had three known species, native toChina, theHimalayas andSoutheast Asia:[21][22]
The former generaSedirea andHygrochilus were incorporated intoPhalaenopsis subgen.Hygrochilus. The interspecific relationships within the subgenusHygrochilus are poorly understood and are a source of confusion. The type species of the subgenus isPhalaenopsis hygrochila.[18] The species of this subgenus are morphologically distinct from the other subgenera, due to their four pollinia and spurred flowers, as well as their unusually long stems.[citation needed]
SeeList ofPhalaenopsis species
SeeList ofPhalaenopsis species
Species ofPhalaenopsis are found from India tosouthern China,Indochina,Malaysia and fromIndonesia to thePhilippines andNew Guinea. There is a single species,Phalaenopsis rosenstromii,endemic toQueensland, Australia.[23]Phalaenopsis stuartiana has become naturalised in Costa Rica, Panama, and Suriname.[24]
Pollination ofPhalaenopsis pulcherrima through bees, specificallyAmegilla nigritar, has been recorded in China.[25] This species employs a deceptive pollination strategy. The orchid does not provide rewards to pollinators. It benefits from blooming in the same period as rewarding species.Amegilla is the most important pollinator, but diurnal insects – such as four species of bees, two species of butterflies, one species of moth and two other unidentified insects – have also been observed to interact with the flowers.[26]
Many species are highly threatened. For instancePhalaenopsis lindenii is categorized as endangered,[27]Phalaenopsis violacea is categorized as vulnerable[28] andPhalaenopsis micholitzii is categorized as critically endangered.[29] Some species, likeP. javanica, are believed to be extinct in the wild.[30][31]
Phalaenopsis, abbreviatedPhal in thehorticultural trade,[32] are among the most popular orchids sold as potted plants, owing to the ease of propagation and flowering under artificial conditions. They were among the first tropical orchids inVictorian collections. Since the advent of thetetraploid hybridPhalaenopsis Doris, they have become extremely easy to grow and flower in the home, as long as some care is taken to provide them with conditions that approximate their native habitats. Their commercial production has become an industry.
If very healthy, aPhalaenopsis plant may have up to ten or more leaves. They bloom in their full glory for several weeks. If kept in the home, the flowers may last two to three months after which aPhalaenopsis orchid will need to conserve energy for further leaf, bud, and root development.[33]
In nature,Phalaenopsis species are typically fond of warm temperatures, thriving in temperatures around 20 to 35°C (68–95 °F), but are adaptable to conditions more comfortable for human habitation in temperate zones (15 to 30 °C or 59–86 °F); at temperatures below 18 °C (64.4 °F) overwatering causes root rot and the plants will also drop their leaves if they experience temperatures below 60 °F for extended periods.Phalaenopsis prefer moderate humidity (60–70%) and low light of 12,000 to 20,000lux. However, Phalaenopsis orchids can adapt to the lower humidity found in most homes. They are also typically hardier than other species of orchids, and this makes them particularly popular among first-time orchid growers.[34]
The flower spikes appear from the pockets near the base of each leaf. The first sign is a light green "mitten-like" object that protrudes from the basal leaf tissue. Over approximately three months the spike elongates until it begins to swell fat buds that will bloom.[citation needed]
It previously was believed that flowering is triggered by a night-time drop in temperature of around 5 to 6 degrees over two to four consecutive weeks, usually in the fall, and a day-time drop in temperature to below 29 °C (84 °F). Using twoPhalaenopsis clones, Matthew G. Blanchard and Erik S. Runkle (2006) established that, other culture conditions being optimal, flower initiation is controlled by daytime temperatures declining below 27 °C (81 °F), with a definite inhibition of flowering at temperatures exceeding 29 °C (84 °F). The long-held belief that reduced evening temperatures control flower initiation inPhalaenopsis was shown to be false. Rather, lower daytime temperatures influence flowering, while night time temperatures do not appear to have any effect.[35]
In cultivation in the United Kingdom, the following have been awarded theRoyal Horticultural Society'sAward of Garden Merit:
Media related toPhalaenopsis at Wikimedia Commons
