What is "disa"

disa \disa\ n. any orchid of the genus Disa, a genus of beautiful orchids with dark green leaves and usually hooded flowers; -- they are much prized as emblematic flowers in their native regions.

1. n. any orchid of the genus Disa; beautiful orchids with dark green leaves and usually hooded flowers; much prized as emblematic flowers in their native regions

2. a combat support agency in the Department of Defense responsible for developing and operating and supporting information systems to serve the needs of the President and the Secretary of Defense and the Joint Chiefs of Staff [syn: Defense Information Systems Agency]

Disa is a genus of flowering plants in the family Orchidaceae. It comprises about 182 species. Most of the species are indigenous to tropical and southern Africa, with a few more in the Arabian Peninsula, Madagascar, and Réunion. Disa bracteata is naturalized in Western Australia, where the local name is "African weed-orchid."

The species Disa uniflora is well known as an ornamental. It is a spectacular red orchid known as "The Pride of Table Mountain." Other commonly cultivated species include Disa aurata, Disa cardinalis, Disa crassicornis, Disa racemosa, Disa sagittalis, and Disa tripetaloides. Some of the species are grown only in African gardens.

The genus Disa was named by P.J. Bergius in 1767. It was named after Disa, the heroine of a Swedish legend.

The plants grow from a fleshy tuberous root which is a source of maltodextrins which are used as a sugar substitute. Some species attain a height of 90 cm. The flowers are solitary or arranged in racemes. The petals and the lip are small. The flowers consist essentially of the sepals. The flowers range in color from very light to dark red.

Disa exhibits a variety of pollination syndromes. Each species of Disa usually has a single species as pollinator and nearly every available pollinating insect is employed by some species of Disa. Species that adapted to the same pollinator often independently evolved a similar floral morphology which confounded the infrageneric classification of Disa until cladistic analysis was applied to DNA sequences from this genus.

Examples of convergent evolution in Disa include the following:

• flowers pollinated by butterflies have evolved twice, for example the pollination of Disa uniflora by the Table mountain Pride Butterfly Aeropetes tulbaghia ( Satyrinae)
• flowers with conspicuous deception, pollinated by carpenter bees, have evolved twice.
• long-spurred flowers, pollinated by long-tongued flies, have evolved four times.
• night-scented flowers, pollinated by moths, have evolved three times.

Disa serves as an example of how speciation can be caused by changes in pollinator availability and evolution.

Some Disa species are pollinated by sunbirds and have pollinaria that stick to the feet of the sunbirds when they perch on the inflorescence.

Once very rare in cultivation, Disa uniflora is gaining in popularity as a cut flower. However, they are difficult to grow, because of the needed mineral composition of the potting soil. Also, if exposed to excessive moisture, they can be easily killed by rot.

In Genera Orchidacearum volume 2, Disa and Schizodium compose the subtribe Disinae of the tribe Diseae. After that volume was published in 2001, molecular phylogenetic studies showed that Schizodium is nested within Disa. Schizodium comprises only six species, all endemic to South Africa.

In a classification of orchids that was published in 2015, Chase et alii placed Schizodium in synonymy under Disa. They also defined the subtribe Disinae as consisting of Pachites, Disa and Huttonaea. This version of Disinae is probably not monophyletic, but was created as a holding classification, to avoid the unnecessary designation of subtribes before further studies can clarify the relationships of these three genera.

Disa is the heroine of a Swedish legendary saga, which was documented by Olaus Magnus, in 1555. It is believed to be from the Middle Ages, but includes Old Norse themes.

It was elaborated by Johannes Messenius in his drama Disa, which was the first historic play in the Swedish language, and was played at the Disting of 1611. It was also presented in an exaggerated version by Olaus Rudbeck in his Atlantica (1685–89)

Disa is a heroine of Swedish mythology.

Disa or DISA may also refer to:

Disa is a female given name. It may be a short form of Hjördis and other names ending in -dis, or a variant of Desideria.

DISA is a company founded in Denmark (with the name Compagnie Madsen A/S) which since 1900 has produced metal casting products.

In 1936 it changed name from Dansk Rekyl Riffel Syndikat A/S to Dansk Industri Syndikat A/S and was a defence manufacturer most notable for producing the Madsen machine gun and Madsen M-50.