Dietes
Encyclopedia
Dietes is a genus
of rhizomatous
plant
s of the family Iridaceae
. Common names include Fortnight lily, African iris, Morea or Moraea iris, Japanese iris and Butterfly iris, each of which may be used differently in different regions for one or more of the four species
within the genus.
Most species are native to southern Africa
, with one (Dietes robinsoniana
) native to Lord Howe Island
off the coast of Australia
.
These plants were formerly placed in the genus Moraea
, but were reclassified because they are rhizomatous
. Like Moraea, they differ from Iris
in having flowers with six free tepal
s that are not joined into a tube at their bases.
Some references mention the species Dietes vegeta or D. vegeta variegata, springing from some confusion with Moraea vegata (which grows from a corm
, not a rhizome). The name D. vegeta is commonly misapplied to both D. grandiflora or D. iridioides.
The genus name is derived from the Greek
words di-, meaning "two", and etes, meaning "affinities".
Species include:
D. bicolor has cream or yellow flowers. D. grandiflora and D. iridioides both have white flowers marked with yellow and violet, and appear similar in photographs, but they are quite different: those of grandiflora are much larger, last three days, and have dark spots at the base of the outer tepals, while those of iridioides are small, last only one day, and lack the spots. D. grandiflora is also a larger plant overall.
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...
of rhizomatous
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
s of the family Iridaceae
Iridaceae
The Iris family or Iridaceae is a family of perennial, herbaceous and bulbous plants included in the monocot order Asparagales, taking its name from the genus Iris. Almost worldwide in distribution and one of the most important families in horticulture, it includes more than 2000 species...
. Common names include Fortnight lily, African iris, Morea or Moraea iris, Japanese iris and Butterfly iris, each of which may be used differently in different regions for one or more of the four 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...
within the genus.
Most species are native to southern 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...
, with one (Dietes robinsoniana
Dietes robinsoniana
Dietes robinsoniana, the Lord Howe Wedding Lily is only found naturally growing at Lord Howe Island. It grows on cliff faces, often in exposed situations. Found also on forest margins and the tops of Mount Gower and Mount Lidgbird and behind the beaches on Lord Howe Island.This is the largest plant...
) native to Lord Howe Island
Lord Howe Island
Lord Howe Island is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, directly east of mainland Port Macquarie, and about from Norfolk Island. The island is about 11 km long and between 2.8 km and 0.6 km wide with an area of...
off the coast of Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
Taxonomic history
Dietes is probably the most primitive member of the Old World tribe Irideae. It shares characteristics of both Iris and the African genus Moraea and is most likely close to the ancestral stock that gave rise to these more specialized genera.These plants were formerly placed in the genus Moraea
Moraea
Moraea is a genus of plants in the family Iridaceae. The genus name is a tribute to the English botanist Robert Moore.The technical botanical material in this entry is abstracted largely from “The Genera of Southern African Flowering Plants”-Description:...
, but were reclassified because they are rhizomatous
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
. Like Moraea, they differ from Iris
Iris (plant)
Iris is a genus of 260-300species of flowering plants with showy flowers. It takes its name from the Greek word for a rainbow, referring to the wide variety of flower colors found among the many species...
in having flowers with six free tepal
Tepal
Tepals are elements of the perianth, or outer part of a flower, which include the petals or sepals. The term tepal is more often applied specifically when all segments of the perianth are of similar shape and color, or undifferentiated, which is called perigone...
s that are not joined into a tube at their bases.
Some references mention the species Dietes vegeta or D. vegeta variegata, springing from some confusion with Moraea vegata (which grows from a corm
Corm
A corm is a short, vertical, swollen underground plant stem that serves as a storage organ used by some plants to survive winter or other adverse conditions such as summer drought and heat ....
, not a rhizome). The name D. vegeta is commonly misapplied to both D. grandiflora or D. iridioides.
The genus name is derived from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
words di-, meaning "two", and etes, meaning "affinities".
Species
Dietes comprises six species, five African and one remarkable disjunct on Lord Howe Island between Australia and New Zealand, D. robinsoniana. The South African D. bicolor appears more closely related to D. robinsoniana than to the other African species, and these two share several characters primitive in the genus. The remaining four African species include the wide-ranging D. iridioides, which extends from the southern Cape to Ethiopia, and three more localized eastern southern African species.Species include:
- Dietes bicolorDietes bicolorDietes bicolor is a clump-forming rhizomatous perennial plant with long sword-like pale-green leaves, growing from multiple fans at the base of the clump. This species belongs to the Iridaceae family. It can form large clumps if left undisturbed for years...
(Yellow Wild Iris, Peacock Flower, Butterfly Iris) - Dietes grandifloraDietes grandifloraDietes grandiflora is a rhozomatous perennial plant with long, rigid, sword-like green leaves belonging to the Iridaceae family. This species is common in horticulture in its native South Africa, where it is often used in public gardens, beautification of commercial premises and along...
(Wild Iris, Large Wild Iris, Fairy Iris) - Dietes iridioidesDietes iridioidesDietes iridioides is an ornamental plant in the Iridaceae family....
(Wild Iris, African Iris, Cape Iris, Fortnight Lily, Morea Iris) - Dietes robinsonianaDietes robinsonianaDietes robinsoniana, the Lord Howe Wedding Lily is only found naturally growing at Lord Howe Island. It grows on cliff faces, often in exposed situations. Found also on forest margins and the tops of Mount Gower and Mount Lidgbird and behind the beaches on Lord Howe Island.This is the largest plant...
(Wedding Lily)
D. bicolor has cream or yellow flowers. D. grandiflora and D. iridioides both have white flowers marked with yellow and violet, and appear similar in photographs, but they are quite different: those of grandiflora are much larger, last three days, and have dark spots at the base of the outer tepals, while those of iridioides are small, last only one day, and lack the spots. D. grandiflora is also a larger plant overall.