Commelina

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Commelina
Two-blue-petals bgiu 02.jpg
Commelina communis flower with typical arrangement of floral parts: 3 staminodes are present above, 3 fertile stamens below with the central one differing in size and form, and a single style emerging between them (curved in this species).
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Clade: Commelinids
Order: Commelinales
Family: Commelinaceae
Tribe: Commelineae
Genus: Commelina
L.
Type species
Commelina communis
L.
Species

See List of Commelina species

Synonyms [1]
  • ErxlebiaMedik.
  • HedwigiaMedik.
  • LecheaLour.
  • AnanthopusRaf.
  • AllotriaRaf.
  • DirteaRaf.
  • EudipetalaRaf.
  • LarnallesRaf.
  • NephrallesRaf.
  • OvidiaRaf.
  • AllospermaRaf.
  • IsanthinaRchb. ex Steud.
  • HeterocarpusWight
  • DisecocarpusHassk.
  • OmphalothecaHassk.
  • PhaeosphaerionHassk.
  • SpathodithyrosHassk.
  • TrithyrocarpusHassk.
  • AthyrocarpusSchltdl. ex Benth. 1883 not Schltdl. 1855 nor Schltdl. ex Hassk. 1866
  • CommelinopsisPichon

Commelina is a genus of approximately 170 species [2] commonly called dayflowers due to the short lives of their flowers. They are less often known as widow's tears. It is by far the largest genus of its family, Commelinaceae. [3] The Swedish taxonomist Carl Linnaeus of the 18th century named the genus after the two Dutch botanists Jan Commelijn and his nephew Caspar, each representing one of the showy petals of Commelina communis . [2]

The dayflowers are herbs that may be either perennial or annual. They are characterised by their zygomorphic flowers and by the involucral bracts called spathes that surround the flower stalks. [4] These spathes are often filled with a mucilaginous liquid. Each spathe houses either one or two scorpioid cymes, with the upper cyme being either vestigial or bearing from one to several typically male flowers, and the lower cyme bearing several flowers. All members of the genus have alternate leaves. [2]

The Asiatic dayflower ( Commelina communis ) is probably the best known species in the West. It is a common weed in parts of Europe and throughout eastern North America. [2] Several species, such as Commelina benghalensis , are eaten as a leaf vegetable in Southeast Asia and Africa. [5]

Description

Floral diagram of a cyme of Commelina coelestis from Eichler's 1875 "Blutendiagramme" Commelina coelestis - Floral diagram.jpg
Floral diagram of a cyme of Commelina coelestis from Eichler's 1875 "Blütendiagramme"

Plants in the genus are perennial or annual herbs with roots that are usually fibrous or rarely tuberous or rhizomatous. The leaves are distichous (i.e. 2-ranked) or spirally arranged with blades that either lack or have a petiole. The ptyxis, or the way the leaf is folded in the bud, is either involute (i.e. having inrolled margins) or supervolute. [2] [6]

The inflorescences are terminal, meaning the stem terminates with an inflorescence, and often leaf opposed, meaning it emerges at the node with a leaf of a new axillary stem. The inflorescence is composed of one or two cincinni, also called scorpioid cymes, which are monochasia (i.e. cymes with a single branched main false axis) in which the lateral branches arise alternately on opposite sides of the false axis. The distal cincinnus may either be vestigial or contain one to several flowers that are typically male. The proximal cyme is always present and is multi-flowered. The cincinni are enclosed in a folded spathe, a modified leaf, which is often filled with a mucilaginous liquid. The spathe may either have completely distinct margins or they may be fused to varying degrees at the basal end. [2] [6]

The flowers are borne on pedicels and are strongly zygomorphic, meaning there is only a single plane of symmetry. Bracteoles occasionally subtend the pedicels, but they are usually absent. The flowers are either bisexual or male. There are three unequal sepals, which may either be free or the two lateral ones may be fused. The petals are free and unequal with the two upper ones being larger and clawed while the lower petal is typically reduced and often differs in colour from the other two. Flower colour is most typically blue, but lilac, lavender, yellow, peach, apricot and white also occur. There are three stamens and two to three staminodes, or infertile stamens, all of which have free, glabrous filaments. The staminodes occur posteriorly and have antherodes with four to six lobes. The stamens are anterior and are longer than the staminodes. The medial stamen differs in size and form from the lateral two, and when a central staminode is present it also differs from the other staminodes. The ovaries are bi- or trilocular and one to two ovules is present per locule. [2] [6]

The fruit is a capsule that is typically bi- or trilocular, but in rare cases may be unilocular, and it is bi- or trivalved. The locules may contain one or two seeds, or no seed at all. The seeds are uniseriate (i.e. arranged in a single row), have a linear hilum and a lateral embryotega. [6]

Related Research Articles

<span class="mw-page-title-main">Stamen</span> Male organ of a flower

The stamen is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium.

<span class="mw-page-title-main">Bract</span> Modified or specialized leaf

In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture. Typically, they also look different from the parts of the flower, such as the petals or sepals. A plant having bracts is referred to as bracteate or bracteolate, while one that lacks them is referred to as ebracteate and ebracteolate, without bracts.

<span class="mw-page-title-main">Commelinaceae</span> Family of flowering plants

Commelinaceae is a family of flowering plants. In less formal contexts, the group is referred to as the dayflower family or spiderwort family. It is one of five families in the order Commelinales and by far the largest of these with about 731 known species in 41 genera. Well known genera include Commelina (dayflowers) and Tradescantia (spiderworts). The family is diverse in both the Old World tropics and the New World tropics, with some genera present in both. The variation in morphology, especially that of the flower and inflorescence, is considered to be exceptionally high amongst the angiosperms.

<span class="mw-page-title-main">Sabiaceae</span> Family of flowering plants

Sabiaceae is a family of flowering plants that were placed in the order Proteales according to the APG IV system. It comprises three genera, Meliosma, Ophiocaryon and Sabia, with 66 known species, native to tropical to warm temperate regions of southern Asia and the Americas. The family has also been called Meliosmaceae Endl., 1841, nom. rej.

<i>Commelina tuberosa</i> Species of flowering plant

Commelina tuberosa is an herbaceous perennial plant in the dayflower family which is native to Mexico but grown worldwide as an ornamental plant. It is characterized by its purple-splotched spathes with free margins, its bright blue petals of equal size, its tuberous roots, and its four to ten flowered lower cymes. In the wild, it is encountered in moist fields, open forests, or pine-oak forests. The species is sometimes considered to include the species Commelina coelestis, Commelina dianthifolia, and Commelina elliptica, such as in the Flora Mesoamericana. When these are treated as separate, they are often referred to as the "Commelina tuberosa complex". Horticulturally, the species are often treated as separate entities because of their differing habits and leaf shapes. In this sense, Commelina tuberosa is a low-growing plant with long narrow leaves.

<i>Commelina communis</i> Species of flowering plant

Commelina communis, commonly known as the Asiatic dayflower, is an herbaceous annual plant in the dayflower family. It gets its name because the blooms last for only one day. It is native throughout much of East Asia and northern parts of Southeast Asia. In China, the plant is known as yazhicao, roughly translating to "duckfoot herb", while in Japan it is known as tsuyukusa, meaning "dew herb". It has also been introduced to parts of central and southeastern Europe and much of eastern North America, where it has spread to become a noxious weed. It is common in disturbed sites and in moist soil. The flowers emerge from summer through fall and are distinctive with two relatively large blue petals and one very small white petal.

<i>Aneilema</i> Genus of flowering plants

Aneilema is a genus of monocotyledonous plants of approximately 60 species. The vast majority of the species are native to sub-Saharan Africa, but a few are found in Oceania and one, Aneilema brasiliense, is from South America. It is the third largest genus in the family Commelinaceae after Commelina and Tradescantia, and it is one of only six genera in the family to occur in both the Eastern Hemisphere and the Western Hemisphere.

<i>Commelina diffusa</i> Species of flowering plant

Commelina diffusa, sometimes known as the climbing dayflower or spreading dayflower, is a pantropical herbaceous plant in the dayflower family. It has been introduced to the southeastern United States where it is most common in wet disturbed soils. There are two recognised varieties, one being the type and the other being C. diffusa var. gigas, which is native to Asia and has been introduced to Florida. It flowers from spring to fall and is most common in disturbed situations, moist places and forests. In China the plant is used medicinally as a febrifuge and a diuretic. A blue dye is also extracted from the flower for paints. In the Hawaiian Islands, it is known as "honohono grass", although it is technically not a grass. "Honohono" refers to the alternating structure of the leaves. At least one publication lists it as an edible plant in New Guinea.

<i>Commelina caroliniana</i> Species of plant

Commelina caroliniana, sometimes known as the Carolina dayflower, is an herbaceous plant in the dayflower family native to India and Bangladesh. Both the scientific name and the common name are misleading as the plant was described based on specimens found in the southeastern United States before it was known that the plant had in fact been introduced from India. It was most likely introduced to South Carolina in the late 17th century along with rice seed from India. The plant has also been recently reported from South Korea. Its flowers emerge from summer to fall and rarely into the winter.

<i>Commelina benghalensis</i> Species of flowering plant

Commelina benghalensis, commonly known as the Benghal dayflower, tropical spiderwort, or wandering Jew, kanshira in Bengali, is a perennial herb native to tropical Asia and Africa. It has been widely introduced to areas outside its native range, including to the neotropics, Hawaii, the West Indies and to both coasts of North America. It has a long flowering period, from spring to fall in subtropical areas, and throughout the year closer to the equator. It is often associated with disturbed soils.

This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology. For other related terms, see Glossary of phytopathology, Glossary of lichen terms, and List of Latin and Greek words commonly used in systematic names.

<i>Commelina lukei</i> Species of flowering plant

Commelina lukei is a monocotyledonous, herbaceous plant in the dayflower family from East Africa. This blue-flowered herb has been recorded in lowland areas of Kenya, Tanzania, and Madagascar, where it is found in a variety of habitats ranging from forests to grasslands to roadsides. Described in 2008, the species was previously confused with Commelina mascarenica and Commelina imberbis. Despite this misinterpretation, a third similar species, Commelina kotschyi, is actually most closely related to C. lukei. The plant's distinctive features include a scrambling habit, capsules with a rounded extension at the apex, appendaged seeds, clasping leaf bases throughout, and solely needle-like hairs along the upper side of the leaf's midrib. The species was named in honour of the botanist W. Q. R. Luke, whose collection of the plant served as the type specimen and allowed for a complete illustration and description.

Commelina sphaerorrhizoma is a monocotyledonous, herbaceous plant in the dayflower family from south-central Africa. This blue-flowered herb has been recorded from western Zambia, central Angola, and the southern portion of the Democratic Republic of the Congo, although at the time of its description it was known only from 11 collections and may be more broadly distributed. It is found in a variety of habitats ranging from woodlands to grasslands to roadsides. The plant's most distinctive feature and the source of its scientific name is its moniliform rhizome composed of spherical segments that can form a bead-like chain. Other distinguishing characteristics include glaucous leaves with clasping bases, unfused and virtually hairless spathes, capsules composed of three, one-seeded locules, and very large seeds with a hairy surface.

<i>Commelina dianthifolia</i> Species of flowering plant

Commelina dianthifolia, known as the birdbill dayflower, is a perennial herb native to mountains in the south-western United States and northern Mexico. Petals are blue while sepals are green. The inflorescence is a scorpioid cyme and it is subtended by a boat-like spathe.

<i>Geogenanthus ciliatus</i> Species of flowering plant

Geogenanthus ciliatus is a flowering plant species in the family Commelinaceae. As currently circumscribed, the genus Geogenanthus includes two other species, G. poeppigii and G. rhizanthus.

<i>Cartonema</i> Genus of flowering plants

Cartonema is a genus of perennial or annual monocotyledonous flowering plants in the dayflower family. It is restricted to Australia and nearby Trangan Island, which is part of Indonesia. It is the earliest diverging member of its family and has a number of traits that are unique within it, such as non-succulent leaves and a lack of raphides. Its distinctive features led to the genus to once be considered part of its own separate family, Cartonemataceae. However, analysis of DNA sequences, as well as many common anatomical characters, has supported its relationship with the Commelinaceae. It contains about 11 species.

<i>Buforrestia</i> Genus of flowering plants

Buforrestia is a genus of perennial monocotyledonous flowering plants in the dayflower family. The genus contains three known species, with two found in West and Central Africa and one in northeastern South America.

<i>Coleotrype</i> Genus of flowering plants

Coleotrype is a genus of perennial monocotyledonous flowering plants in the dayflower family. It is found in Africa and Madagascar.

Commelina hockii is an herbaceous plant in the dayflower family found primarily in Central Africa, from southwestern Tanzania in the east, west through the Democratic Republic of the Congo and Zambia, and possibly extending further west to Angola. The species' distinctive features include its long, tapering spathes with unfused margins, its white flowers, and its many-flowered lower cymes. It can be found in grasslands and Brachystegia-dominated woodland. It is fairly unusual among Commelina species in having variation in the color of the antherodes, with some individuals having entirely yellow antherodes, while others contain a dark spot in the center. Also, it is one of the only Commelina species known to leave a papery residue of dried fluid inside its spathes; normally only fused-spathe species are known to produce this substance. Only one specimen from Angola resembles this species, but it has blue flowers, suggesting it may be a poorly understood and as-yet undescribed separate species. Commelina hockii is probably closely related to Commelina kituloensis, which shares a similar fruit type, the same tufted perennial habit, similar large spathes with dried fluid substance, and equally numerously flowered inflorescences. That species differs in having purplish flowers, hairy leaves, shorter spathes, and a preference for high altitude grassland.

<span class="mw-page-title-main">Floral morphology</span>

In botany, floral morphology is the study of the diversity of forms and structures presented by the flower, which, by definition, is a branch of limited growth that bears the modified leaves responsible for reproduction and protection of the gametes, called floral pieces.

References

  1. Kew World Checklist of Selected Plant Families
  2. 1 2 3 4 5 6 7 Faden, Robert (2006), "Commelina", Flora of North America online, vol. 22, New York & Oxford: Oxford University Press
  3. Acevedo-Rodriguez, Pedro; Strong, Mark T. (2005), "Monocotyledons and Gymnosperms of Puerto Rico and Virgin Islands", Contributions of the United States National Herbarium, 52: 157–158
  4. Hong, Deyuan; DeFillipps, Robert A. (2000), "Commelina diffusa", in Wu, Z. Y.; Raven, P.H.; Hong, D.Y. (eds.), Flora of China, vol. 24, Beijing: Science Press; St. Louis: Missouri Botanical Garden Press, p. 35
  5. Qaiser, M.; Jafri, S.M.H. (1975), "Commelina benghalensis", in Ali, S.I.; Qaiser, M. (eds.), Flora of Pakistan, vol. 84, St. Louis: University of Karachi & Missouri Botanical Garden, p. 10
  6. 1 2 3 4 Faden, Robert (1998), "Commelina", in Kubitzki, K. (ed.), The Families and Genera of Vascular Plants, vol. 4, Berlin: Springer, p. 126