Angraecum
Encyclopedia
The genus
Angraecum, abbreviated as Angcm in horticultural trade, common name Angrek (Indonesian
and Malay
) or Comet Orchid, contains about 220 species
, some of them among most magnificent of all orchids. They are quite varied vegetatively and florally and are adapted to dry tropical woodland habitat and have quite fleshy leaves as a consequence. Most are epiphyte
s, but a few are lithophyte
s.
Tropical Africa
and Madagascar
contain the majority of the genus with one outlier found on Sri Lanka, and three species once thought to belong to the genus in Japan and the Philippines. But these orchids can also be found on the Comoros
, the Seychelles
, and the Mascarenes. They occur between sea level and 2,000m in humid regions.
The long-lasting flowers are racemose and grow from the leaf axils. They are mostly white, but a few are yellow, green or ochre. They all have a long spur at the back of the labellum
(lip).
In the case of Angraecum sesquipedale
, a species from Madagascar, on observing the 30cm spur in the lip, Charles Darwin
made the hypothesis that, since the nectar was at the bottom of the spur, a pollinator
must exist with a tongue at least that long. Otherwise the orchid could never be pollinated. At the time, he was not believed. However, in 1903, the predicted pollinator was discovered, a hawk moth then named Xanthopan morganii praedicta
("praedicta" meaning "the predicted one"). It has an appropriately long proboscis. The specific name sesquipedale means "one foot and a half", referring to the length of the spur. This is a perfect example of mutual dependence of an orchid and a specific pollinator.
Angraecum Veitchii: a very rewarding orchid. In indirect light and watered/fed regularly this plant will produce blooms annually (usually in Late Winter to Spring - for Australia this occurs in August - excellent for those wanting to show their plants at Brisbane's Ekka! You will notice a few lovely specimens there in the Gardening Exhibits). The flowers last a while if kept in a sheltered position and their strong heady fragrance is delightful. They only release their perfume at night. Flowers are large (4 - 9 cm across), waxy, white to greenish cream in colour and borne on stems of seven to ten depending on the faithfulness of your fertilising, watering, and indirect light provision. The leaves are large, thick straps that alternately fan out from a central (monopodal) stem. Pups (keikis) form at the base of the stem and can either be divided from the parent plant once they have at least three roots of their own or alternatively, left on the plant these will make a stunning specimen as when mature will produce blooms with the parent plant - many award winning angraecum veitchiis are grown as such. In the right conditions these orchids are healthy and require little attention. As they are epiphites the potting mixture should be loose and free draining. Prolific roots are formed from the base and also amongst the lower half of the foliage. These are attractive although somewhat troublesome when moving plants to and from shows. Once your angraecum is big it is best to pot it in a heavy terracotta pot or place a brick in the bottom of the pot in order to ensure your beauty does not get top heavy and risk snapping when blown over in the wind (especially since they flower during the windier times of the year, this can be very sad). When watering a good soaking with a hose or watering-can is best (not just a misting from a spray gun) as this helps to flush away any salts from fertilisers that may be present in the potting mixture and also thoroughly wets the plant. Make sure the roots halfway up the stem get a soaking too, not just the potted roots. This is a great orchid and will give you years of pleasure. They're slow growing and require little attention. Very hard to kill.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Angraecum, abbreviated as Angcm in horticultural trade, common name Angrek (Indonesian
Indonesian language
Indonesian is the official language of Indonesia. Indonesian is a normative form of the Riau Islands dialect of Malay, an Austronesian language which has been used as a lingua franca in the Indonesian archipelago for centuries....
and Malay
Malay language
Malay is a major language of the Austronesian family. It is the official language of Malaysia , Indonesia , Brunei and Singapore...
) or Comet Orchid, contains about 220 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, some of them among most magnificent of all orchids. They are quite varied vegetatively and florally and are adapted to dry tropical woodland habitat and have quite fleshy leaves as a consequence. Most are epiphyte
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
s, but a few are lithophyte
Lithophyte
Lithophytes are a type of plant that grows in or on rocks. Lithophytes feed off moss, nutrients in rain water, litter, and even their own dead tissue....
s.
Tropical Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
and Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
contain the majority of the genus with one outlier found on Sri Lanka, and three species once thought to belong to the genus in Japan and the Philippines. But these orchids can also be found on the Comoros
Comoros
The Comoros , officially the Union of the Comoros is an archipelago island nation in the Indian Ocean, located off the eastern coast of Africa, on the northern end of the Mozambique Channel, between northeastern Mozambique and northwestern Madagascar...
, the Seychelles
Seychelles
Seychelles , officially the Republic of Seychelles , is an island country spanning an archipelago of 115 islands in the Indian Ocean, some east of mainland Africa, northeast of the island of Madagascar....
, and the Mascarenes. They occur between sea level and 2,000m in humid regions.
The long-lasting flowers are racemose and grow from the leaf axils. They are mostly white, but a few are yellow, green or ochre. They all have a long spur at the back of the labellum
Labellum
Labellum is the Latin diminutive of labium, meaning lip. These are anatomical terms used descriptively in biology, for example in Entomology and botany.-Botany:...
(lip).
In the case of Angraecum sesquipedale
Angraecum sesquipedale
Angraecum sesquipedale is an epiphytic orchid in the genus Angraecum that is endemic to Madagascar. The orchid was first discovered by the French botanist Louis-Marie Aubert du Petit-Thouars in 1798, but was not described until 1822...
, a species from Madagascar, on observing the 30cm spur in the lip, Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
made the hypothesis that, since the nectar was at the bottom of the spur, a pollinator
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...
must exist with a tongue at least that long. Otherwise the orchid could never be pollinated. At the time, he was not believed. However, in 1903, the predicted pollinator was discovered, a hawk moth then named Xanthopan morganii praedicta
Xanthopan morgani
Xanthopan morgani, or Morgan's Sphinx, is a very large hawk moth from West Africa and Madagascar. It is the sole member of its genus, and little is known of the biology, though the adults have been found to visit orchids .In January 1862 while researching insect pollination of orchids, Charles...
("praedicta" meaning "the predicted one"). It has an appropriately long proboscis. The specific name sesquipedale means "one foot and a half", referring to the length of the spur. This is a perfect example of mutual dependence of an orchid and a specific pollinator.
Angraecum Conservation
Many species of Angraecum orchid are considered to be at risk of extinction in the wild and are protected from international trade under CITES. The genus Angraecum is listed as one of the top conservation priorities by the International Union for Conservation of Nature and Natural Resources (IUCN) Orchid Specialist Group. Many of the species, such as Angraecum sororium, are endemic to Madagascar and are threatened from over collecting, loss of hawkmoth pollinators, habitat fragmentation, and fire.Growing Angraecums
Much like all other orchids, Angraecums have no need for special care or attention. Like all other orchids it is best to water in the mornings to avoid fungal rot due to overnight dampness. Feeding as per other orchids and similar light conditions: in humid and hot regions (sub tropical) feed fortnightly during growing season (Summer) with a certified orchid fertiliser following directions on packet, weaker solutions are also okay if you're worried. In summer water weekly or more depending on situation. Angraecums flower best when in a lighter position. Keep out of direct sunlight as this can damage (and eventually kill) the plant. Most Angraecums will have their leaves for a number of years so any sun burn spots are ugly for a significant period and also may expose your plant to disease. In indirect sunlight the Angraecums will reward you with blooms and attractive growth.Angraecum Veitchii: a very rewarding orchid. In indirect light and watered/fed regularly this plant will produce blooms annually (usually in Late Winter to Spring - for Australia this occurs in August - excellent for those wanting to show their plants at Brisbane's Ekka! You will notice a few lovely specimens there in the Gardening Exhibits). The flowers last a while if kept in a sheltered position and their strong heady fragrance is delightful. They only release their perfume at night. Flowers are large (4 - 9 cm across), waxy, white to greenish cream in colour and borne on stems of seven to ten depending on the faithfulness of your fertilising, watering, and indirect light provision. The leaves are large, thick straps that alternately fan out from a central (monopodal) stem. Pups (keikis) form at the base of the stem and can either be divided from the parent plant once they have at least three roots of their own or alternatively, left on the plant these will make a stunning specimen as when mature will produce blooms with the parent plant - many award winning angraecum veitchiis are grown as such. In the right conditions these orchids are healthy and require little attention. As they are epiphites the potting mixture should be loose and free draining. Prolific roots are formed from the base and also amongst the lower half of the foliage. These are attractive although somewhat troublesome when moving plants to and from shows. Once your angraecum is big it is best to pot it in a heavy terracotta pot or place a brick in the bottom of the pot in order to ensure your beauty does not get top heavy and risk snapping when blown over in the wind (especially since they flower during the windier times of the year, this can be very sad). When watering a good soaking with a hose or watering-can is best (not just a misting from a spray gun) as this helps to flush away any salts from fertilisers that may be present in the potting mixture and also thoroughly wets the plant. Make sure the roots halfway up the stem get a soaking too, not just the potted roots. This is a great orchid and will give you years of pleasure. They're slow growing and require little attention. Very hard to kill.
Hybrids
- Angraecum cv.CultivarA cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
'Lemforde White Beauty' (Angcm. sesquipedale × Angcm. magdalenae). - Angraecum × veitchii (cv. 'White Star') (Angcm. sesquipedale × Angcm. eburneum).
External links
- http://www.orchids.mu/Species/Angraecum/Images/Angraecum_veitchii.jpg
- http://research.kahaku.go.jp/database/tukuba_ran/angr.gif