Bract

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 often (but not always) 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. The state of having bracts is referred to as bracteate[1] or bracteolate, and conversely the state of lacking them is referred to as ebracteate[2] and ebracteolate, without bracts.

Yellow-rattle close 700
Papery (upper) and leafy bracts on hay rattle (Rhinanthus minor). All the "leaves" in this image are bracts.

Variants

Some bracts are brightly-coloured and serve the function of attracting pollinators, either together with the perianth or instead of it. Examples of this type of bract include Euphorbia pulcherrima (poinsettia) and Bougainvillea: both of these have large colourful bracts surrounding much smaller, less colourful flowers.

In grasses, each floret (flower) is enclosed in a pair of papery bracts, called the lemma (lower bract) and palea (upper bract), while each spikelet (group of florets) has a further pair of bracts at its base called glumes. These bracts form the chaff removed from cereal grain during threshing and winnowing.

Bats may detect acoustic signals from dish-shaped bracts such as those of Marcgravia evenia.[3]

A prophyll is a leaf-like structure, such as a bracteole, subtending (extending under) a single flower or pedicel. The term can also mean the lower bract on a peduncle.

The frequently showy pair of bracts of Euphorbia species in subgenus Lacanthis are the cyathophylls.

Bracts subtend the cone scales in the seed cones of many conifers, and in some cases, such as Pseudotsuga, they extend beyond the cone scales.

Bougainvillea glabra

Bracts of Bougainvillea glabra, differ in colour from the non-bract leaves, and attract pollinators.

Banana bract

Bracts along a banana flower stalk surround the rows of flowers

E milii vulcanii ies

Euphorbia milii var. vulcanii cyathia bearing a pair of pinkish cyathophylls.

Ananas bracteatus var tricolor

Colourful bracts of Ananas bracteatus.

IMG 1527Dogwood

Dogwood species Cornus florida inflorescence showing four large white bracts and central flower cluster.

2013-05-10 08 26 08 Closeup of pink dogwoods at the Brendan T. Byrne State Forest headquarters

Cornus florida dogwood with pink bracts surrounding small flower cluster.

Bracteole

A small bract is called a bracteole or bractlet. Technically this is any bract that arises on a pedicel instead of subtending it.

Involucral bracts

Leafy-bract-Beggar-ticks.we
Beggar-tick (Bidens comosa)

Bracts that appear in a whorl subtending an inflorescence are collectively called an involucre. An involucre is a common feature beneath the inflorescences of many Apiaceae, Asteraceae, Dipsacaceae and Polygonaceae. Each flower in an inflorescence may have its own whorl of bracts, in this case called an involucel. In this case they may be called chaff, paleas, or receptacular bracts and are usually minute scales or bristles. Many asteraceous plants have bracts at the base of each inflorescence.

The term involucre is also used for a highly conspicuous bract or bract pair at the base of an inflorescence. In the family Betulaceae, notably in the genera Carpinus and Corylus, the involucre is a leafy structure that protects the developing nuts. Beggar-tick (Bidens comosa) has narrow involucral bracts surrounding each inflorescence, each of which also has a single bract below it. There is then a pair of leafy bracts on the main stem and below those a pair of leaves.

Epicalyx

An epicalyx, which forms an additional whorl around the calyx of a single flower, is a modification of bracteoles[4] In other words, the epicalyx is a group of bracts resembling a calyx or bracteoles forming a whorl outer to the calyx.[5] It is a calyx-like extra whorl of floral appendages. Each individual segment of the epicalyx is called an episepal because they resemble the sepals in them.[6] They are present in the Malvaceae, the Hibiscus family. Fragaria (strawberries) may or may not have an epicalyx.

Spathe

Anthurium scherzerianum 2
Anthurium scherzerianum inflorescence with spathe and spadix

A spathe is a large bract or pair of bracts forming a sheath to enclose the flower cluster of such plants as palms, arums, irises,[7] crocuses,[8] and dayflowers (Commelina). Habranthus tubispathus in the Amaryllidaceae derives its specific name from its tuberous spathe. In many arums (Araceae family), the spathe is petal-like, attracting pollinators to the flowers arranged on a type of spike called a spadix.

References

  1. ^ "the definition of bracteate". Dictionary.com. Archived from the original on 2017-04-28. Retrieved 2017-04-27.
  2. ^ "Definition of Ebractate". www.greengonzo.com. Archived from the original on 2017-04-28. Retrieved 2017-04-27.
  3. ^ Ralph Simon; Marc W. Holderied; Corinna U. Koch; Otto von Helversen. "Floral acoustics: Conspicuous echoes of a dish-shaped leaf attract bat pollinators". Science. 333 (6042): 631–633. doi:10.1126/science.1204210. PMID 21798950.
  4. ^ Darpan, Pratiyogita (June 2006). Competition Science Vision. Pratiyogita Darpan. p. 136.
  5. ^ "Archived copy" (PDF). Archived (PDF) from the original on 2010-12-14. Retrieved 2010-08-15.CS1 maint: Archived copy as title (link)
  6. ^ "epicalyx – Dictionary of botany". Botanydictionary.org. Archived from the original on 2012-05-01. Retrieved 2012-04-29.
  7. ^ Richard Lynch The Book of the Iris, p. 203, at Google Books
  8. ^ Alex Casha Flora of the Maltese Islands, p. 287, at Google Books
Abaca bract mosaic virus

Abaca bract mosaic virus (ABrMV) is a plant pathogenic virus of the family Potyviridae. Attempts have been made to sequence ABrMV.

Allium koreanum

Allium koreanum, the Korean rocky chive, is a species of Allium endemic to the Korean Peninsula.It has three to six leaves that are 20–54 cm (7.9–21.3 in) long and 2–7.4 cm (0.79–2.91 in) wide, and a sheath that is 7.6–22.4 cm (3.0–8.8 in) long. The pyxidium is obtuse, triangular and solid. Purple-red flowers bloom in August to November; 74 to 197 flowers form an umbel at the end of a 10–22.2 mm (0.39–0.87 in) long flower stalk. The bract is broadovate, with a caudate end. Perianth lobes are broadoval and 3.8–7.2 cm (1.5–2.8 in) long with a round end and green midrib on the underside.

Araceae

The Araceae are a family of monocotyledonous flowering plants in which flowers are borne on a type of inflorescence called a spadix. The spadix is usually accompanied by, and sometimes partially enclosed in, a spathe or leaf-like bract. Also known as the arum family, members are often colloquially known as aroids. This family of 114 genera and about 3750 known species is most diverse in the New World tropics, although also distributed in the Old World tropics and northern temperate regions.

The largest collection of living Araceae is maintained at the Missouri Botanical Gardens. Another large collection of living Araceae can be found at the Munich Botanical Garden, due to the efforts of researcher and aroid authority Josef Bogner.

Athrotaxis

Athrotaxis is a genus of two to three species (depending on taxonomic opinion) of conifers in the cypress family, Cupressaceae. The genus is endemic to western Tasmania, where they grow in high altitude temperate rainforests.They are medium-sized evergreen trees, reaching 10–30 m (rarely 40 m) tall and 1-1.5 m trunk diameter. The leaves are scale-like, 3–14 mm long, are borne spirally on the shoots. The cones are globose to oval, 1–3 cm diameter, with 15-35 scales, each scale with 3-6 seeds; they are mature in 7–9 months after pollination, when they open to release the seeds. The male (pollen) cones are small, and shed their pollen in early spring.They are very susceptible to bush fires, and have declined markedly in abundance due to accidental and deliberate fires since the European colonisation of Tasmania.

Banana bract mosaic virus

Banana bract mosaic virus (BBrMV) is a plant pathogenic virus of the family Potyviridae.

Coeloglossum

Coeloglossum is a genus of orchids. It has long been considered to have only one species, Coeloglossum viride, the frog orchid. Some recent classifications regard Coeloglossum as part of the larger genus, Dactylorhiza, so that C. viride becomes Dactylorhiza viridis. Other sources continue to keep Coeloglossum viride separate.Under either name, the species has a wide distribution across the cooler parts of the Northern Hemisphere, covering much of Europe, non-tropical Asia (Russia, Japan, China, the Himalayas, etc.), much of Canada and parts of the United States (Alaska, Northeast, the Appalachians, Great Lakes Region, Northern Great Plains, and Rocky Mountains). It is typically found growing in moist, rich soil in wet meadows, moist or wet deciduous woods and thickets, and is frequently found on steep slopes.

Conifer cone

A cone (in formal botanical usage: strobilus, plural strobili) is an organ on plants in the division Pinophyta (conifers) that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity. The name "cone" derives from the fact that the shape in some species resembles a geometric cone. The individual plates of a cone are known as scales.

The male cone (microstrobilus or pollen cone) is structurally similar across all conifers, differing only in small ways (mostly in scale arrangement) from species to species. Extending out from a central axis are microsporophylls (modified leaves). Under each microsporophyll is one or several microsporangia (pollen sacs).

The female cone (megastrobilus, seed cone, or ovulate cone) contains ovules which, when fertilized by pollen, become seeds. The female cone structure varies more markedly between the different conifer families, and is often crucial for the identification of many species of conifers.

Cornus nuttallii

Cornus nuttallii, the Pacific dogwood or mountain dogwood, is a species of dogwood native to western North America from the lowlands of southern British Columbia to the mountains of southern California, with an inland population in central Idaho. Cultivated examples are found as far north as Haida Gwaii. It is a small to medium-sized deciduous tree, reaching 10–25 m tall.

The leaves are opposite, simple, oval, 8–12 cm long, and 5–8 cm broad. The flowers are individually small and inconspicuous, 2–3 mm across, produced in a dense, rounded, greenish-white flowerhead 2 cm diameter; the 4-8 large white "petals" are actually bracts, each bract 4–7 cm long and broad. The fruit is a compound pink-red berry about 3 cm diameter, containing 50-100 small seeds; it is edible, though not very palatable.

Like the related Cornus florida, it is very susceptible to dogwood anthracnose, a disease caused by the fungus Discula destructiva. This has killed many of the larger plants in the wild and also restricted its use as an ornamental tree.

Cornus nuttallii is named after Thomas Nuttall, an English botanist and zoologist who worked in North America in the nineteenth century.

Some Plateau Indian tribes used the bark as a laxative and emetic.

Corylus heterophylla

Corylus heterophylla, the Asian hazel, is a species of hazel native to eastern Asia in northern and central China, Korea, Japan, and southeastern Siberia.It is a deciduous shrub or small tree growing to 7 m (23 ft) tall, with stems up to 20 cm (8 in) thick grey bark. The leaves are rounded, 4–13 cm (1 1⁄2–5 in) long and 2.5–10 cm (1–4 in) broad, with a coarsely double-serrated to somewhat lobed margin and an often truncated apex. The flowers are wind-pollinated catkins; the male (pollen) catkins are pale yellow, 4 cm (1 1⁄2 in) long, while the female catkins are bright red and only 1–3 mm (1⁄16–1⁄8 in) long. The fruit is a nut produced in clusters of 2–6 together; each nut is 0.7–1.5 cm (1⁄4–1⁄2 in) diameter, partly enclosed in a 1.5–2.5 cm (1⁄2–1 in) long, bract-like involucre (husk).It is very similar to the closely related common hazel (C. avellana) of Europe and western Asia, differing in the leaves being somewhat more lobed.

Fir

Firs (Abies) are a genus of 48–56 species of evergreen coniferous trees in the family Pinaceae. They are found through much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range. Firs are most closely related to the genus Cedrus (cedar). Douglas firs are not true firs, being of the genus Pseudotsuga.

They are large trees, reaching heights of 10–80 m (33–262 ft) tall with trunk diameters of 0.5–4 m (1 ft 8 in–13 ft 1 in) when mature. Firs can be distinguished from other members of the pine family by the way in which their needle-like leaves are attached singly to the branches with a base resembling a suction cup, and by their cones, which, like those of true cedars (Cedrus), stand upright on the branches like candles and disintegrate at maturity.

Identification of the different species is based on the size and arrangement of the leaves, the size and shape of the cones, and whether the bract scales of the cones are long and exserted, or short and hidden inside the cone.

Glume

In botany, a glume is a bract (leaf-like structure) below a spikelet in the inflorescence (flower cluster) of grasses (Poaceae) or the flowers of sedges (Cyperaceae). There are two other types of bracts in the spikelets of grasses: the lemma and palea.

In grasses, two bracts known as "glumes" form the lowermost organs of a spikelet (there are usually 2 but 1 is sometimes reduced; or rarely, both are absent). Glumes may be similar in form to the lemmas, the bracts at the base of each floret.

In sedges, by contrast, a glume is a scale at the base of each flower in a spikelet.

Inflorescence

An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed. The modifications can involve the length and the nature of the internodes and the phyllotaxis, as well as variations in the proportions, compressions, swellings, adnations, connations and reduction of main and secondary axes.

Inflorescence can also be defined as the reproductive portion of a plant that bears a cluster of flowers in a specific pattern.

The stem holding the whole inflorescence is called a peduncle and the major axis (incorrectly referred to as the main stem) holding the flowers or more branches within the inflorescence is called the rachis. The stalk of each single flower is called a pedicel. A flower that is not part of an inflorescence is called a solitary flower and its stalk is also referred to as a peduncle. Any flower in an inflorescence may be referred to as a floret, especially when the individual flowers are particularly small and borne in a tight cluster, such as in a pseudanthium.

The fruiting stage of an inflorescence is known as an infructescence.

Inflorescences may be simple (single) or complex (panicle). The rachis may be one of several types, including single, composite, umbel, spike or raceme.

Libocedrus bidwillii

Libocedrus bidwillii, also called pāhautea, kaikawaka or New Zealand cedar, is a species of Libocedrus, endemic to New Zealand in both the North and South Islands; in the North Island, it occurs from Te Aroha southward. It grows at 250–1,200 m altitude in temperate rainforests.It is an evergreen coniferous tree growing to 25 m tall, with a trunk up to 1.5 m diameter. The foliage is arranged in flattened sprays; the leaves are scale-like, 1.5–2 mm long and 1 mm broad, arranged in opposite decussate pairs on the shoots. The seed cones are cylindrical, 8–12 mm long, with four scales each with a prominent curved spine-like bract; they are arranged in two opposite decussate pairs around a small central columella; the outer pair of scales is small and sterile, the inner pair large, bearing two winged seeds. They are mature about six to eight months after pollination. The pollen cones are 2.5–5 mm long.

The timber seldom becomes commercially available. It is very light in weight and a distinct light purple when cut. The timber in small dimension sizes is prone to spiral and twist when cut. It is sometimes used for lightweight sailing boat construction. It glues and holds ring nails well.

This species is named after J. C. Bidwill, the New Zealand botanist and explorer.

Libocedrus chevalieri

Libocedrus chevalieri is a species of conifer in the cypress family, Cupressaceae. It is endemic to New Caledonia, occurring in three small, isolated populations on low mountain summits at 650–1,620 m altitude in cloud forest scrub on serpentine soils. It is threatened by habitat loss.It is an evergreen coniferous shrub (rarely a small tree) growing to 5 m tall, often multi-stemmed, with trunks up to 10 cm diameter. The foliage is arranged in flattened sprays; the leaves are scale-like, 2.5–5 mm long and 2–2.5 mm broad, arranged in opposite decussate pairs on the shoots. The seed cones are cylindrical, 12–16 mm long, with four scales each with a prominent curved spine-like bract; they are arranged in two opposite decussate pairs around a small central columella; the outer pair of scales is small and sterile, the inner pair large, each bearing two winged seeds. They are mature about six to eight months after pollination. The pollen cones are 8–10 mm long.

Libocedrus yateensis

Libocedrus yateensis is a species of Libocedrus, endemic to New Caledonia, occurring in a few small, isolated populations in low altitude riverside sites at 150–600 m altitude in rainforest scrub. It is threatened by habitat loss.It is an evergreen coniferous shrub or small tree growing to 12 m tall, sometimes multi-stemmed, with trunks up to 30 cm diameter. The foliage is arranged in flattened sprays; the leaves are scale-like, arranged in opposite decussate pairs on the shoots; the facial leaves are 1.5–2 mm long and 1 mm broad, and the lateral leaves slightly larger, 2–5 mm long and 1–2 mm broad. The seed cones are cylindrical, 9–10 mm long, with four scales each with a prominent curved spine-like bract; they are arranged in two opposite decussate pairs around a small central columella; the outer pair of scales is small and sterile, the inner pair large, each bearing two winged seeds. They are mature about six to eight months after pollination. The pollen cones are 5–8 mm long.

List of banana cultivars

The following is a list of banana cultivars and the groups into which they are classified. Almost all modern cultivated varieties (cultivars) of edible bananas and plantains are hybrids and polyploids of two wild, seeded banana species, Musa acuminata and Musa balbisiana. Cultivated bananas are almost always seedless (parthenocarpic) and hence sterile, so they are propagated vegetatively (cloned). They are classified into groups according to a genome-based system introduced by Ernest Cheesman, Norman Simmonds, and Ken Shepherd, which indicates the degree of genetic inheritance from the two wild parents and the number of chromosomes (ploidy). Cultivars derived from Musa acuminata are more likely to be used as dessert bananas, while those derived from Musa balbisiana and hybrids of the two are usually plantains or cooking bananas.

Mentzelia involucrata

Mentzelia involucrata is a species of Mentzelia native to the Mojave and Sonoran deserts of North America. Its common names include kuʼu, sand blazing star and white-bract blazing star.

Oxytheca perfoliata

Oxytheca perfoliata is a species of flowering plant in the buckwheat family known by the common names round-leaf puncturebract and roundleaf oxytheca. It is native to the southwestern United States, where it is a common plant of the deserts and some woodland and valley areas. It is an annual herb producing a leafless stem up to about 20 centimeters in maximum height in the spring; during the winter the plant is a small rosette of oblong or spoon-shaped leaves a few centimeters wide. The plant is red-veined green, or often brown to maroon or magenta in color. The inflorescence atop the stem is punctuated by nodes at which the bracts are fused to form a cup or band up to about 2.5 centimeters wide. At the end of each branching of the stem is a similar cup of bracts partially fused around a cluster of flowers. The bracts are tipped in spinelike awns. The flowers are white to yellow-green and hairy in texture.

Spadix (botany)

In botany, a spadix ( SPAY-diks; plural spadices SPAY-dih-seez, spay-DY-seez) is a type of spike inflorescence having small flowers borne on a fleshy stem. Spadices are typical of the family Araceae, the arums or aroids. The spadix is typically surrounded by a leaf-like curved bract known as a spathe. For example, the "flower" of the well known Anthurium spp. is a typical spadix with a large colorful spathe.Monoecious aroids have unisexual male and female flowers on the same individual and the spadix is usually organized with female flowers towards the bottom and male flowers towards the top. Typically, the stigmas are no longer receptive when pollen is released which prevents self-fertilization.

We also have Compound Spadix Inflorescence in which the axis is branched. Usually whole Inflorescence is covered by a stiff boat shaped path for example- Coconut.

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