|Angraecum sesquipedale subsp. var.||Darwin's orchid, Christmas orchid, Star of Bethlehem orchid, King of the Angraecums|
Angraecum sesquipedale (also called Darwin's orchid, Christmas orchid, Star of Bethlehem orchid, and King of the Angraecums) 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. It is noteworthy for its long spur and its association with the naturalist Charles Darwin who surmised that the flower was pollinated by a then undiscovered moth with a proboscis whose length was then unprecedented. His prediction had gone unverified until 21 years after his death when the moth was discovered and his conjecture vindicated. The story of its postulated pollinator has come to be seen as one of the celebrated predictions of the theory of evolution.Angraecum sesquipedale is a monocot with monopodial growth and can get to a height of 1 m ft 1. Its growth habit is rather similar to species in the genus Aerides.There are also two variations of this species known as A. sesquipedale var. sesquipedale and A. sesquipedale var. angustifolium. A. sesquipedale var. angustifolium tends to be smaller than A. sesquipedale and has narrower leaves. The chromosome number of A. sesquipedale is 2n=42. A. sesquipedale has also previously gone by the synonyms Aeranthes sesquipedalis Lindl. (1824), Macroplectrum sesquipedale Pfitzer (1889), Angorchis sesquepedalis Kuntze (1891), Mystacidium sesquipedale Rolfe (1904), and Angraecum bosseri Senghas (1973).
It is often found in lowlands in Madagascar at altitudes below 100 m ft , near the east coast of the island, and on trees that are at the edge of forests. Usually it is attached to trees with fewer leaves and to areas of the branch or trunk that are driest. This allows the plant to obtain a great deal of light and air movement. Rarely A. sesquipedale is also found growing as a lithophyte and sometimes even as a semi-terrestrial. The orchid lives in an environment with heavy rainfall, up to 150 in cm per year. There is no dry season so the growing season is continuous.
|Standard Cyclopedia of Horticulture|
Macroplectrum sesquipedale, Pfitz. (Angraecum sesquipedale, Thouars. Aeranthus sesquipedalis, Lindl.). Sts. 2-3 ft. tall: lvs. oblong-ligulate, 12 in. long and up to 2 in. broad, unequally 2-lobed: peduncle 2-5-fld.; fls. 5-7 in. across, fleshy, ivory-white; sepals and petals similar, acuminate; Up oblong-ovate, cordate, acuminate, irregularly serrate. Madagascar.
Star-like waxy flowers are produced on 30 cm in 1 inflorescences arising from the stem from June to November in the wild with most flowers wilting by August. When cultivated in Europe however, the plant flowers between December and January. This flowering habit is what lends the orchid several of its common names, such as "Comet orchid" due to the shape of its flower and "Christmas orchid" due to the timing of its flowering. Each flower opens up with a green color, but eventually turns white with tones of light green. The amount of green in each flower can vary from plant to plant. It is claimed that the age-dependent color change is more pronounced in wild A. sesquipedale than in greenhouse-grown plants. The sepals tend to stay green for a longer time than petals. As the flower ages further it goes from white to yellowish and then from orange to brown as it begins to wilt. A distinctive feature of the flowers is that they have a long green spur attached. The spur of the flower is 27 – 43 cm from its tip to the tip of the flower's lip. The specific name sesquipedale is Latin for "one and a half feet," referring to the spur length. At the end of the spur is a small amount of nectar usually about 40–300 µl in volume. In general, longer spurs tend to have greater concentrations of nectar. This nectar fills the spur up to within 7 to 25 cm from the bottom of the spur. The nectar has been found to contain the sugars fructose, sucrose, glucose, and raffinose. The flowers produce an extremely intense spicy scent that can easily fill a room; this fragrance is only present during the night. Usually 1 to 4 flowers are produced at a time.
Angraceum sesquipedale was first brought to the United Kingdom in 1855 to be grown outside of its natural environment. Subsequently, William Ellis achieved the first flowering of the plant in cultivation in 1857. The first Angraecum hybrid was created by John Seden, an employee of Veitch Nurseries, and exhibited for the first time on January 10, 1899. It was named Angcm. Veitchii, but it also commonly goes by the name the King of the Angraceum hybrids. The cross was between A. sesquipedale and A. eburneum subsp. superbum. Another common ciross involving A. sesquipedale is Angcm. Crestwood, which is a cross between Angcm. Veitchii and A. sesquipedale. Angraecum sesquipedale is seldom grown in private collections, despite its enormous importance to Darwin's concept of co-evolution and subsequently the fields of botany and evolutionary biology.
It's often recommended that A. sesquipedale be grown under warm to intermediate conditions and given as much light as possible without burning the leaves. Angraecum sesquipedale is commonly found to have a slow growth habit, but the orchid can be expected to produce flowers even before it has reached an adult size. Angraecum sesquipedale is notorious for having sensitive roots. The roots of the plant should be disturbed as little as possible and one should be especially careful during repotting. Disturbing the roots can cause the plant to sulk for 2 to 4 years or even to cause it to die. It is advisable to plant the orchid in a coarse medium to minimize disturbances to the roots. Also planting it in a basket or large pot is best since this allows the orchid to grow for many years before having to have its roots disturbed.
Pests and diseases
- Angcm. Orchidglade (A. sesquipedale x A. giryamae)
- Angcm. Appalachian Star (A. sesquipedale x A. praestans)
- Angcm. Dianne's Darling (A. sesquipedale x Angcm. Alabaster)
- Angcm. Malagasy (A. sesquipedale x A. sororium)
- Angcm. North Star (A. sesquipedale x A. leonis)
- Angcm. Sesquibert (A. sesquipedale x A. humbertii)
- Angcm. Star Bright (A. sesquipedale x A. didieri)
- Angcm. Rose Ann Carroll (A. eichlerianum x A. sesquipedale)
- Angcm. Sesquivig (A. viguieri x A. sesquipedale)
- Angcm. Veitchii (A. eburneum subsp. superbum x A. sesquipedale)
- Angcm. Crestwood (Angcm. Veitchii x A. sesquipedale)
- Angcm. Ol Tukai (A. comorense x A. sesquipedale)
- Angcm. Lemförde White Beauty (A. magdalenae x A. sesquipedale)
- Chouara Kaohsiung Dream (A. sesquipedale x Dtps. Ruey Lih Beauty)
- Eugcm. Lydia (A. sesquipedale x Echn. rothschildiana)
- Angth. Sesquimosa (Aerth. ramosa x A. sesquipedale)
- ↑ Petit-Thouars, Histoire Particulière des Plantes Orchidées Recueillies sur les trois Isles Australs d'Afrique (1822)
- ↑ 2.0 2.1 2.2 William Ellis (1858). Three Visits to Madagascar during the years 1853-1854-1856, including a journey to the capital; with notices of the natural history of the country and of the present civilisation of the people.
- ↑ Bosser & Morat, Adansonia, n.s., 12: 77 (1972).
- ↑ The Kew checklist lists A. sesquipedale var. sesquipedale, but it doesn't provide any references to the literature in which it is described and so its possible that this variation simply doesn't exist.
- ↑ 5.0 5.1 Joyce Stewart, Johan Hermans, and Bob Campbell, (2006). Angraecoid Orchids: Species from the African Region [ILLUSTRATED] (Hardcover), Timber Press, ISBN 0881927880.
- ↑ Jones, Keith. The Chromosomes of Orchids: II: Vandeae Lindl., p.151
- ↑ Flora 68: 381. 1885.
- ↑ Die Natürlichen Pflanzenfamilien 2(6): 215. 1889.
- ↑ Revisio Generum Plantarum 2: 651. 1891.
- ↑ Orchid Review 12: 47. 1904.
- ↑ 11.0 11.1 11.2 Charles Marden Fitch (2004). The best orchids for indoors, Brooklyn Botanic Garden, ISBN 1889538604.
- ↑ Cite error: Invalid
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- ↑ In a paper published by Wasserthal in 1997 he quoted a spur length of 33.3±4.6 cm (N=15). The spur was measured from the rostellum at the spur entrance to the end of the spur lumen.
- ↑ David, Jeffrey C., Sugar Content in Floral and Extrafloral Exudates of Orchids: Pollination, Myrmecology and Chemotaxonomy Implication, p. 192
- ↑ 15.0 15.1 Gard. Chron. 1899, vol. xxv. p. 31.
- ↑ Alec Pridgeon (2006). The Illustrated Encyclopedia of Orchids, Timber Press. ISBN 0881928011.
- ↑ There is some ambiguity in the literature as to the parentage of this hybrid. Some sources claim that the seed parent is A. eburneum subsp. superbum, while others like the Royal Horticultural Society claims it's simply A. eburneum and that (A. eburneum subsp. superbum x A. sesquipedale) should be called Angcm. Memoria Mark Aldridge.
- ↑ The Royal Horticultural Society,The International Orchid Register.
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963