Tepal

A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very similar appearance), as in Magnolia, or because, although it is possible to distinguish an outer whorl of sepals from an inner whorl of petals, the sepals and petals have similar appearance to one another (as in Lilium). The term was first proposed by Augustin Pyramus de Candolle in 1827 and was constructed by analogy with the terms "petal" and "sepal".[1][2] (De Candolle used the term perigonium or perigone for the tepals collectively; today this term is used as a synonym for "perianth".[3])

Mature flower diagram
Diagram showing the parts of a mature flower. In this example the perianth is separated into a calyx (sepals) and corolla (petals)

Origin

Zanlophator1a.UME
A Lilium flower showing the six tepals: the outer three are sepals and the inner three are petals.

Undifferentiated tepals are believed to be the ancestral condition in flowering plants. For example, Amborella, which is thought to have separated earliest in the evolution of flowering plants,[4] has flowers with undifferentiated tepals. Distinct petals and sepals would therefore have arisen by differentiation, probably in response to animal pollination. In typical modern flowers, the outer or enclosing whorl of organs forms sepals, specialised for protection of the flower bud as it develops, while the inner whorl forms petals, which attract pollinators.

Tepals formed by similar sepals and petals are common in monocotyledons, particularly the "lilioid monocots". In tulips, for example, the first and second whorls both contain structures that look like petals. These are fused at the base to form one large, showy, six-parted structure (the perianth). In lilies the organs in the first whorl are separate from the second, but all look similar, thus all the showy parts are often called tepals. Where sepals and petals can in principle be distinguished, usage of the term "tepal" is not always consistent – some authors will refer to "sepals and petals" where others use "tepals" in the same context.

In some plants the flowers have no petals, and all the tepals are sepals modified to look like petals. These organs are described as petaloid, for example, the sepals of hellebores. When the undifferentiated tepals resemble petals, they are also referred to as "petaloid", as in petaloid monocots, orders of monocots with brightly coloured tepals. Since they include Liliales, an alternative name is lilioid monocots.

Properties and shape

Terms used in the description of tepals include pubescent (with dense fine, short, soft hairs, downy), puberulent (minutely pubescent, hairs barely visible to the naked eye) and puberulous (dense covering of very short soft hairs). Tepal shape is described in similar terms to those used for leaves (see Glossary of leaf morphology).

Gallery

Magnolia-x-alba-bud-comparison

Flowers of Magnolia × alba showing tepals in various stages of development

2006-12-18Helleborus niger19

A hellebore flower showing the petaloid sepals

Sternbergia lutea showing the different parts of the flower

A Sternbergia lutea flower showing the two whorls of tepals

Tulip - floriade canberra02

A tulip flower showing the petal-like tepals

See also

References

  1. ^ Augustin Pyramus de Candolle (1827). Organographie végétale, ou Description raisonnée des organes des plantes; pour servir de suite et de développement a la théorie élémentaire de la botanique, et d'introduction a la physiologie végétale et a la physiologie végétale et a la description des familles. Paris: Deterville. p. 503.
  2. ^ Augustin Pyramus de Candolle (1841). Vegetable organography; or, An analytical description of the organs of plants. 2. Translated by Boughton Kingdon. London: Houlston & Stoneman. p. 90.
  3. ^ Stearn, William Thomas (2004). Botanical Latin (p/b ed.). David & Charles/Timber Press. ISBN 978-0-7153-1643-6. p. 39.
  4. ^ Ronse De Craene, L. P. (2007). "Are Petals Sterile Stamens or Bracts? The Origin and Evolution of Petals in the Core Eudicots". Annals of Botany. 100 (3): 621–630. doi:10.1093/aob/mcm076. PMC 2533615. PMID 17513305.

Botany: A Brief Introduction To Plant Biology - 5th ed. Thomas L. Rost; T. Elliot Weier - Wiley & Sons 1979 ISBN 0-471-02114-8.

Plant Systematics - Jones; Samuel - McGraw-Hill 1979 ISBN 0-07-032795-5.

Acute

Acute may refer to:

Acute accent

Acute angle

Acute triangle

Acute leaf shape

Acute tepal shape

Acute (medicine)

Acute (phonetic)

Acute toxicity

Allium lehmannii

Allium lehmannii is a plant species endemic to southern Italy. It is found only the Island of Sicily in the Mediterranean and in the nearby Calabria region of the Italian mainland.Allium lehmannii is a perennial, bulb-forming herb up to 30 cm tall. Leaves are very narrow and thread-like. Flowers are narrowly bell-shaped, the tepal tips spreading outwards but most of the tepals wrapping closely around the anthers and style. Tepals are white with a deep violet midvein.

Allium macrum

Allium macrum, the rock onion, is an American species of wild onion native to the eastern and central parts of the US States of Oregon and Washington. It grows on gravelly soils at elevations up to 1400 m.Allium macrum produces round to egg-shaped bulbs up to 2 cm long. Flowers are white with a green stripe running the length of each tepal. Anthers and pollen are yellow.

Chionodoxa luciliae

Chionodoxa luciliae (syn. C. gigantea), the Bossier's glory-of-the-snow or Lucile's glory-of-the-snow, is a bulbous perennial from west Turkey flowering in early spring. After flowering, it goes into dormancy until the next spring. The Latin name is in honour of Lucile, the wife of the Swiss botanist Pierre Edmond Boissier.Like all members of the genus Chionodoxa, the bases of the stamens are flattened and closely clustered in the middle of the flower. In the related genus Scilla, the stamens are not flattened or clustered together. The differences are not considered by some botanists as sufficient to create a separate genus, so they include this species in Scilla.Each bulb produces two leaves, up to 8 cm long and 2 cm wide, and at most one flowering stem, up to 10 cm long. The flowers are produced in a loose pyramidal raceme, with 2–3 flowers per stem, which face upwards. Each flower is up to 3.5 cm across. The base of each tepal is white (as are the stamen filaments), producing a white 'eye'. The outer part of the tepals is violet-blue. The species can be distinguished from the commonest form grown in gardens, C. siehei, by the much smaller number of slightly larger flowers per stem.Under its synonym Scilla luciliae this plant has gained the Royal Horticultural Society's Award of Garden Merit. (confirmed 2017).

Colchicum byzantinum

Colchicum byzantinum (Byzantine meadow saffron) is a species of flowering plant in the family Colchicaceae with a long history of cultivation, and no certain place of origin, which means it could be a hybrid of other species. Therefore its correct designation may be Colchicum × byzantinum (unresolved).It shares many traits with Colchicum cilicicum. The flowers have no scent and are light pink with a prominent central white stripe. Each tepal has a purple tip, even white selections. This plant is very reliable in gardens, and has gained the Royal Horticultural Society’s Award of Garden Merit (confirmed 2017).

Crocus sieberi

Crocus sieberi, Sieber's crocus, also referred to as the Cretan crocus or snow crocus (as is Crocus chrysanthus), is a plant of the genus Crocus in the family Iridaceae. A small, early blooming crocus, it easily naturalises, and is marked by a brilliant orange which is mostly confined to the stamens and style, fading through the bottom third of the tepal. It grows wild generally in the Balkans and Greece, especially in the island Crete. There are four subtypes: sieberi (Crete), atticus (Attica area around Athens), nivalis and sublimis. Its cultivars are used as ornamental plants. Height: 3–4 inches (7.6–10.2 cm).

Epicephala vitisidaea

Epicephala vitisidaea is a moth of the family Gracillariidae. It is found in Fujian, China and on the Ryukyu Archipelago.

The larvae feed on the seeds of Breynia vitis-idaea. The adult is the pollinator of the host plant. Eggs are placed in the interspace between the tepal and ovary, so the ovipositor does not penetrate floral tissue.

Fritillaria lusitanica

Fritillaria lusitanica is a European plant in the lily family, native to Spain and Portugal.Fritillaria lusitanica is a bulb-forming perennial. The flowers are nodding (hanging), purple, sometimes with a green stripe along the central part of each tepal.

SubspeciesFritillaria lusitanica subsp. lusitanica

Fritillaria lusitanica subsp. stenophylla (Boiss. & Reut.) K.Richtformerly includedSeveral other names have been coined at the varietal and subspecific levels for taxa once thought to be parts of the species Fritillaria lusitanica but now considered better suited to other species.

Fritillaria lusitanica var. algeriensis, now called Fritillaria oranensis

Fritillaria lusitanica subsp. macrocarpa, now called Fritillaria macrocarpa

Fritillaria lusitanica var. neglecta, now called Fritillaria messanensis subsp. neglecta

Fritillaria lusitanica subsp. neglecta, now called Fritillaria messanensis subsp. neglecta

Fritillaria lusitanica subsp. oranensis, now called Fritillaria oranensis

Fritillaria rhodocanakis

Fritillaria rhodocanakis is a Greek species of plants in the lily family. In its pure form, it is found only on Hydra Island (also called Ydra or Hydrea or Ύδρα) and on small neighboring islands. Additional populations occur in the Peloponnisos region of mainland Greece, though the specimens there show some degree of hybridization with F. spetsiotica and F. graeca. In 1987, some of the hybrids were described with the name Fritillaria rhodocanakis subsp. argolica, but this is now generally referred to as Fritillaria × spetsiotica Kamari.Fritillaria rhodocanakis is a bulb-forming perennial herb. Flowers are nodding (hanging downwards), each tepal purple with a yellow tip.The species is listed as endangered by the IUCN.

Gagea divaricata

Gagea divaricata is an Asian species of plants in the lily family, native to Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan, and Xinjiang Province of western China.Gagea divaricata is a bulb-forming perennial up to 5 cm tall. Flowers are yellow with a green stripe on the backside of each tepal.

Gagea pratensis

Gagea pratensis, called the yellow star-of-Bethlehem, is a European and Mediterranean plant species in the lily family. It is widespread across much of Europe as well as Turkey and Morocco. It was first described to science by Persoon in 1794.Gagea pratensis is a bulb-forming perennial. Flowers are generally yellow, sometimes with a green stripe along the backside of each tepal.

formerly includedGagea pratensis var. paczoskii, now called Gagea transversalis

Glaucium corniculatum

Glaucium corniculatum, the blackspot hornpoppy or red horned-poppy, is a species of the genus Glaucium in the poppy family (Papaveraceae). It is an annual flowering plant, occurring in southern Europe, and grows up to 1 foot (30 cm) high. The stem and leaves are hairy, the capsule fruit is covered with stiff hair, the flower is red, with a black spot on the base of the tepal bract, which has a yellow margin around it. The flower appears from June until August.

Leucojum vernum

Leucojum vernum, called spring snowflake, is a perennial bulbous flowering plant species in the family Amaryllidaceae (the daffodils). It is native to central and southern Europe from Belgium to Ukraine. It is considered naturalized in north-western Europe, including Great Britain and parts of Scandinavia, and in the US states of Georgia and Florida. It is cultivated as a spring-flowering ornamental bulbous plant. Usually a single white flower with greenish marks near the tip of each tepal is borne on a stem about 10–20 cm tall, occasionally more.

Maianthemum

Maianthemum (Latin Māia "May" and Greek ánthemon "flower"; including former Smilacina) is a genus of rhizomatous, herbaceous, perennial flowering plants, native to the understory of woodlands. It is widespread across much of North America, Europe and Asia.In the APG III classification system, Maianthemum is placed in the family Asparagaceae, subfamily Nolinoideae (formerly the family Ruscaceae).Because of genetic similarity, similar fruits, and evidence that the 4-tepal species evolved from a 6-tepal species, the genus Smilacina was combined with Maianthemum in the late 20th century.Like many lilioid monocots, both Maianthemum and Smilacina were formerly included in the family Liliaceae. The genus has also been placed in the former family Convallariaceae, and resembles the closely related Polygonatum, hence the common name "false Solomon's seal".Flowers have six tepals, reduced to four in M. canadense, M. bifolium and M. dilatatum.

Obtuse

Obtuse may refer to:

Obtuse angle, an angle of between 90 and 180 degrees

Obtuse triangle, a triangle with an internal angle of between 90 and 180 degrees

Obtuse leaf shape

Obtuse tepal shape

Obtuse barracuda, a ray-finned fish

Obtuse, a neighborhood in Brookfield, Connecticut

Persoonia myrtilloides

Persoonia myrtilloides, commonly known as myrtle geebung, is a shrub species that is endemic to New South Wales in Australia. It grows to between 0.5 and 2.5 metres (1.6 and 8.2 ft) in height and has leaves that are between 12 and 50 millimetres (0.47 and 1.97 in) long and 4 to 30 millimetres (0.16 to 1.18 in) wide. Yellow flowers appear between December and April in the species' native range.Persoonia myrtilloides was first formally described in 1827. Two subspecies are currently recognised, distinguished by the shape of leaves and tepals:

P. myrtilloides subsp. cunninghamii (R.Br.) L.A.S.Johnson & P.H.Weston which has broader leaves and reflexed tepal tips.

P. myrtilloides Sieber ex Schult. & Schult.f. subsp. myrtilloides which has narrower leaves and recurved tepal tips.Hybrids with P. acerosa, P. levis and P. recedens have been reported where the parent species both occur.The species occurs in the Blue Mountains from Wentworth Falls northwards to Capertee. Subspecies cunninghamii is found in the Wollemi National Park and the catchment of the Cudgegong River.Both subspecies are understory plants in open forests on sandstone-based soils. Subspecies myrtilloides is associated with trees such as sydney peppermint (Eucalyptus piperita), narrow-leaved peppermint (E. radiata) and silvertop ash (E. sieberi), and a shrubby

understory of old man banksia (Banksia serrata), Phyllota squarrosa, paperbark teatree (Leptospermum trinervium) and mountain devil (Lambertia formosa). It is also found in heath. Subspecies cunninghamii is associated with the trees scribbly gum species Eucalyptus rossii and E. sclerophylla, rough-barked apple (Angophora floribunda), Callitris species, and mallees such as Eucalyptus multicaulis and narrow-leaved mountain mallee (E. apiculata).Currawongs and possibly kangaroos and possums are thought to eat the fruit, the seeds of which are then scattered in droppings. Insects recorded foraging at flowers of subspecies myrtilloides include members of the genera Exoneura, Hylaeus and Odyneurus, Homalictus holochorus, colletid bees of the genus Leioproctus subgenus Cladocerapis, including Leioproctus carinatifrons, L. raymenti, L. speculiferus and Trigona carbonaria.

Petal

Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals, that collectively form the calyx and lie just beneath the corolla. The calyx and the corolla together make up the perianth. When the petals and sepals of a flower are difficult to distinguish, they are collectively called tepals. Examples of plants in which the term tepal is appropriate include genera such as Aloe and Tulipa. Conversely, genera such as Rosa and Phaseolus have well-distinguished sepals and petals. When the undifferentiated tepals resemble petals, they are referred to as "petaloid", as in petaloid monocots, orders of monocots with brightly coloured tepals. Since they include Liliales, an alternative name is lilioid monocots.

Although petals are usually the most conspicuous parts of animal-pollinated flowers, wind-pollinated species, such as the grasses, either have very small petals or lack them entirely.

Sepal

A sepal ( or ) is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom. The term sepalum was coined by Noël Martin Joseph de Necker in 1790, and derived from the Greek σκέπη (skepē), a covering.Collectively the sepals are called the calyx (plural calyces), the outermost whorl of parts that form a flower. The word calyx was adopted from the Latin calyx, not to be confused with calix, a cup or goblet. Calyx derived from the Greek κάλυξ (kalyx), a bud, a calyx, a husk or wrapping, (cf Sanskrit kalika, a bud) while calix derived from the Greek κύλιξ (kylix), a cup or goblet, and the words have been used interchangeably in botanical Latin.After flowering, most plants have no more use for the calyx which withers or becomes vestigial. Some plants retain a thorny calyx, either dried or live, as protection for the fruit or seeds. Examples include species of Acaena, some of the Solanaceae (for example the Tomatillo, Physalis philadelphica), and the water caltrop, Trapa natans. In some species the calyx not only persists after flowering, but instead of withering, begins to grow until it forms a bladder-like enclosure around the fruit. This is an effective protection against some kinds of birds and insects, for example in Hibiscus trionum and the Cape gooseberry. In other species, the calyx grows into an accessory fruit.

Morphologically, both sepals and petals are modified leaves. The calyx (the sepals) and the corolla (the petals) are the outer sterile whorls of the flower, which together form what is known as the perianth.The term tepal is usually applied when the parts of the perianth are difficult to distinguish, e.g. the petals and sepals share the same color, or the petals are absent and the sepals are colorful. When the undifferentiated tepals resemble petals, they are referred to as "petaloid", as in petaloid monocots, orders of monocots with brightly coloured tepals. Since they include Liliales, an alternative name is lilioid monocots. Examples of plants in which the term tepal is appropriate include genera such as Aloe and Tulipa. In contrast, genera such as Rosa and Phaseolus have well-distinguished sepals and petals.The number of sepals in a flower is its merosity. Flower merosity is indicative of a plant's classification. The merosity of a eudicot flower is typically four or five. The merosity of a monocot or palaeodicot flower is three, or a multiple of three.

The development and form of the sepals vary considerably among flowering plants. They may be free (polysepalous) or fused together (gamosepalous). Often, the sepals are much reduced, appearing somewhat awn-like, or as scales, teeth, or ridges. Most often such structures protrude until the fruit is mature and falls off.

Examples of flowers with much reduced perianths are found among the grasses.

In some flowers, the sepals are fused towards the base, forming a calyx tube (as in the Lythraceae family, and Fabaceae). In other flowers (e.g., Rosaceae, Myrtaceae) a hypanthium includes the bases of sepals, petals, and the attachment points of the stamens.

Spur (botany)

The botanical term “spur” is given to outgrowths of tissue on different plant organs. The most common usage of the term in botany refers to nectar spurs in flowers.

nectar spur (flower)

spur (stem)

spur (leaf)

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