Corsia | |
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Corsia ornata from Bird's Head Peninsula, Western New Guinea | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Monocots |
Order: | Liliales |
Family: | Corsiaceae |
Genus: | Corsia Becc. [1] |
Type species | |
Corsia ornata | |
Species | |
See text |
Corsia is a little-studied plant genus from the monocotyledon family Corsiaceae. It was first described in 1877 by Italian naturalist Odoardo Beccari and contains 25 species, all of which lack chlorophyll and parasitize fungi for nutrition. All 25 species are distributed through New Guinea, the Bismarck Archipelago, the Solomon Islands and Queensland, Australia.
In terms of appearance, the species of Corsia are quite uniform except for the flowers. [2] Chromosome counts are known only from two species: Corsia cornuta and C. clypeata. Both have a diploid number (2n) of 18. [2] [3]
Corsia exist largely underground; [4] only the seldom-formed flower stems develop above ground. The fine, thread-like and hairless root system is weakly branched and whitish, spreading widely just beneath the surface. Several hairless, unbranched and upright flowering stems sprout from a rhizome and are visible above ground. They are usually reddish in color and are 10 to 28 cm (3.9 to 11.0 in) high. The xylem is woody and not perforated.
The foliage along the stem is evenly distributed, and consists of three to seven broadly ovate pointed leaves. Those on the rhizomes are less developed than the reddish leaves on the flowering stems. Along the stem the leaves grow alternately, at their bases they sheath the stem almost entirely. [4]
The growth of Corsia flowers appears to be triggered by combination of rain and drought, usually by a prolonged rainy season followed by several dry days. The zygomorphic, trimerous, nodding flowers grow singly and are terminal on the stems. [4] The tepals are colored pale red to brownish red, sometimes with a bit of pale yellow and rarely brownish-green.
The six tepals are approximately of the same shape and size, with the exception of the uppermost tepal, termed the labellum, which is considerably larger and usually heart-shaped. [4] The tepals of the species of section Sessilis are 4 to 15 mm (0.16 to 0.59 in) long and 0.5 to 2.5 mm (0.020 to 0.098 in) wide. The tepals of the section Unguiculatis are 3 to 8.5 mm (0.12 to 0.33 in) long and 1 to 3.5 mm (0.039 to 0.138 in) wide. The labellum is about 5 to 25 mm (0.20 to 0.98 in) long and 4 to 22 mm (0.16 to 0.87 in) wide. The labellum encloses the floral bud until its opening, thereby protecting immature floral parts. The labellum is usually simple, but is occasionally bifurcated at the tip of the midrib.
The labellum of Corsia is similar in appearance to the labellum of some orchids, but is not homologous to them; [5] in orchids the labellum is formed from an inner tepal (petal), but in Corsiaceae it forms from an outer tepal (sepal). In Corsia, unlike the orchids, all six stamens are fertile. [5]
After pollination (possibly by flies), the peduncles extend and a 3.5 cm (1.4 in) long and slender cylindrical yellowish brown capsule fruit forms. The small dust-like seeds are about 1 to 3.2 mm (0.039 to 0.126 in) long, 0.3 mm (0.012 in) thick and colored pale to dark brown. The seed coat tightly encloses the endosperm and its surface is finely grooved longitudinally. [6] Although the native habitat of Corsia is relatively calm, seed dispersal is presumed to be facilitated by wind (anemochory). [3]
Species of Corsia are generally found in floodplains and mountain forests at altitudes of 400 to 2,700 m (1,300 to 8,900 ft) above sea level. They grow in humus-rich soils in shaded areas of high humidity among decaying leaves. [4]
The center of diversity for the genus is New Guinea. All species are endemic to New Guinea (including the Bismarck Archipelago), the Solomon Islands, and Australia. [7]
Like other members of Corsiaceae, Corsia species lack chlorophyll and are thus incapable of photosynthesis. Instead, they are myco-heterotrophs, relying exclusively on parasitizing arbuscular mycorrhizal fungi for nutrition. [8] Myco-heterotrophs were once mistakenly thought to be saprotrophic plants. It is now known that they do not obtain nourishment directly from decaying organic matter, instead they digest the hyphae of saprotrophic fungi with enzymes and absorb the resulting nutrients. [9]
The host species of Corsia, and whether Corsia are even host specific, remains unknown. Corsia are sometimes found growing in association with other myco-heterotrophic plants like Burmannia , Sciaphila , and Cotylanthera tenuis .[ citation needed ]
Corsia is classified under the family Corsiaceae of the order Liliales. It is one of the three genera currently classified under Corsiaceae, the other two being Corsiopsis of China and Arachnitis of South America. [9] It differs from the latter two in having several shoots arising from creeping rhizomes. [10]
Corsia was first described in 1877 by the Italian naturalist Odoardo Beccari from specimens from New Guinea. He named it after the Marquis Bardo Corsi Salviati. It was classified under Burmanniaceae by the English botanist George Bentham in 1883 and grouped together with orchids (family Orchidaceae). [11]
In 1938, Fredrik Pieter Jonker separated Arachnitis and Corsia from Burmanniaceae based on their strongly zygomorphic floral characteristics. Kores et al. (1978) also separated Corsia from Burmanniaceae after comparing the chromosome numbers of C. cornuta and C. clypeata (2n = 18) with the rest of Burmanniaceae (2n=32 to 136). Dahlgren & Clifford (1982) tentatively reclassified Corsiaceae as closer to lilies (order Liliales) than to orchids. Cribb et al. (1995) noted the significant differences between Corsia and the only other member of Corsiaceae then - Arachnitis. In 1996, Ibisch et al. challenged the monophyly of Corsiaceae, positing that Arachnitis may actually be more closely related to Orchidaceae than Corsia and recommended the separation of the former into its own family, Arachnitaceae. [11] [12]
Corsiopsis was discovered in 1999 by Zhang et al. and became the third genus included in the family Corsiaceae. Zhang also remarked that Corsiopsis seem to be more closely related to Corsia than to Arachnitis. Based on phylogenetic studies and reexamination of previous morphological studies, Neyland & Hennigan (2003) concluded that Corsia is not closely related to Arachnitis. The former probably has closer affinities with Campynemataceae of Liliales, while the latter may be more closely related to Thismia and/or Burmannia of Dioscoreales. [9] [11] [13] However, Chase et al. (2006) concluded that Arachnitis falls within Liliales while Rudall & Eastman (2002) puts Corsia closer to either Campynemataceae or Thismia. As such, the taxonomic placement of Corsia and Corsiaceae remains problematic though they have been tentatively included in Liliales. [14]
Corsia contains two sections, Unguiculatis and Sessilis, with 25 species. They are listed below along with their distribution ranges: [7] [15] [16] [17]
SectionUnguiculatisP.Royen
SectionSessilisP.Royen
Corsiaceae is a family of monocotyledonous flowering plants. The APG II system (2003) treats the family in the order Liliales, in the clade monocots. This is a slight change from the APG system, of 1998, which left the family unplaced as to order, but did assign it also to the monocots.
Corybas, commonly known as helmet orchids, is a genus of about 120 species of plants in the orchid family, Orchidaceae. Helmet orchids are small, perennial, deciduous herbs and are nearly always terrestrial. They have a single leaf at their base and a single flower on a short stalk, the flower dominated by its large dorsal sepal and labellum. Species of Corybas are found in Australia, New Zealand, New Guinea, Southeast Asia, the Himalayas, southern China, many Pacific islands and a few sub-Antarctic islands.
Didymoplexis, commonly known as crystal orchids or as 双唇兰属 , is a genus of terrestrial leafless orchids in the family Orchidaceae, about twenty species of which have been described. Orchids in this genus have swollen, fleshy rhizomes and thin, pale, upright fleshy flowering stems with resupinate, bell-shaped white or pale yellowish brown flowers. They are native to Africa, Madagascar, Southeast Asia, Australia and various islands of the Pacific.
Bulbophyllum rhodoglossum is a species of orchid in the genus Bulbophyllum, first described by Rudolf Schlechter in 1913 in Repertorium Specierum Novarum Regni Vegetabilis. It is an epiphyte growing in Papua New Guinea on trees in mountain forests around 1000 metres in elevation. The flowers are white, and the labellum red with a yellow tip.
Dendrobium johannis, commonly known as the chocolate tea tree orchid, is a species of epiphytic or lithophytic orchid native to Australia and New Guinea. It has spindle-shaped pseudobulbs, between five and ten dark green leaves with purplish markings and flowering stems with up to fifteen chocolate brown flowers with a yellow labellum.
Brachypeza, commonly known as sage orchids, is a genus of flowering plants from the orchid family, Orchidaceae. Orchids in this genus have short stems with fleshy leaves and arching flowering stems with short-lived flowers. The sepals and petals are similar in size and shape and the labellum is pouch-like and suspended at the base of the flower. Sage orchids occur in tropical areas from Indochina to New Guinea.
Cryptostylis, commonly known as tongue orchids, is a genus of flowering plants from the orchid family. Tongue orchids are terrestrial herbs with one to a few stalked leaves at the base of the flowering stem, or leafless. One to a few dull coloured flowers are borne on an erect flowering stem. The most conspicuous part of the flower is the labellum, compared to the much reduced sepals and petals. At least some species are pollinated by wasps when they attempt to mate with the flower. There are about twenty five species found in South Asia, Southeast Asia and the South Pacific.
Dryadorchis is a genus of flowering plants from the orchid family, Orchidaceae. It is endemic to New Guinea.
Thelasis, commonly known as fly orchids, is a genus of flowering plants from the orchid family, Orchidaceae. Plants in this genus are usually epiphytes, sometimes lithophytes or rarely terrestrials. Some species have pseudobulbs with up to three leaves, whilst others have several leaves in two ranks. A large number of small, white or greenish yellow flowers are borne on a thin, arching flowering stem. There are about thirty species, distributed from tropical and subtropical Asia to the southwest Pacific.
Octarrhena, commonly known as grub orchids, is a genus of flowering plants from the orchid family, Orchidaceae. Plants in this genus are small, orchids with short stems, thin roots, short, thick, fleshy leaves arranged in two ranks and tiny flowers. The labellum is rigidly attached to the base of the column. There are about fifty species native to areas from Sri Lanka and Malesia to the Western Pacific.
Peristylus, sometimes commonly known as ogre orchids or bog orchids is a genus of flowering plants from the orchid family, Orchidaceae. It consists of over 100 known species found across much of eastern and southern Asia as well as in Australia and on many islands of the Indian and Pacific Oceans.
Pomatocalpa, commonly known as bladder orchids, or 鹿角兰属 , is a genus of about twenty five species from the orchid family, Orchidaceae. Plants in this genus are epiphytes or lithophytes with thick, leathery leaves and a large number of small flowers with a three-lobed labellum. There are about twenty five species found from tropical and subtropical Asia to the south-west Pacific.
Saccolabiopsis, commonly known as pitcher orchids, is a genus of flowering plants from the orchid family, Orchidaceae. Plants in this genus are small epiphytes with short, fibrous stems, smooth, thin roots, a few thin, oblong to lance-shaped leaves in two ranks and large numbers of small green flowers on an unbranched flowering stem. There are about fifteen species found from the eastern Himalayas to the south-west Pacific.
Schoenorchis, commonly known as flea orchids, or 匙唇兰属 in Chinese, is a genus of flowering plants from the orchid family, Orchidaceae. Plants in this genus are small epiphytes with thin roots, thin leafy stems with leaves in two ranks and tiny fragrant, almost tube-shaped flowers with a prominently spurred labellum. There are about twenty five species found from tropical and subtropical Asia to the Western Pacific.
Arthrochilus irritabilis, commonly known as clubbed elbow orchid, is a flowering plant in the orchid family (Orchidaceae) and is endemic to Queensland. It has up to five leaves and up to thirty light greenish or reddish, insect-like flower with reddish, hair-like glands on its labellum. There is a single record of this species from Papua New Guinea.
Arthrochilus laevicallus is a species of flowering plant in the orchid family (Orchidaceae) and is endemic to Papua New Guinea. It is leafless but has up to seven green, insect-like flowers with dark reddish glands on its labellum.
Trachoma, commonly known as spectral orchids, is a genus of flowering plants in the family Orchidaceae. Orchids in this genus are epiphytic plants with leafy stems, crowded, leathery leaves arranged in two ranks and a large number of relatively small, short-lived flowers that often open in successive clusters. The sepals and petals are free from and more or less similar to each other, except that the petals are often smaller. The labellum is rigidly fixed to the column and is more or less sac-shaped. There are about 17 species distributed from Assam to the Western Pacific Ocean. Most species grow in rainforests, often on emergent trees such as hoop pine.
Corsia ornata is a species of flowering plant in the genus Corsia of the small family Corsiaceae, part of the monocot order Liliales. They are saprophytes (Myco-heterotrophs), lacking the ability to photosynthesise, being dependent on other organisms for their nutrition. The plant lives underground, sending up purplish stems above ground in order to flower. The leaves are reduced to scales. One of the six petal-like tepals named the labellum, is specialised, being enlarged and hanging protectively over the reproductive organs. It was discovered in New Guinea in 1875, but has since been sighted in Queensland, Australia.