botany Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...

, a bract is a modified or specialized

leaf A leaf (: leaves) is a principal appendage of the plant stem, stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leav ...

, associated with a reproductive structure such as a

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

axis or

cone scale A conifer cone, or in formal botanical usage a strobilus, : strobili, is a seed-bearing organ on gymnosperm plants, especially in conifers and cycads. They are usually woody and variously conic, cylindrical, ovoid, to globular, and have scale ...

. Bracts are usually different from foliage leaves in size, color, shape or texture. They also look different from the parts of the flower, such as the petals or

sepals A sepal () 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., p. 106 Etymology The term ''sepalum'' ...

. A plant having bracts is referred to as bracteate or bracteolate, while one that lacks them is referred to as ebracteate or ebracteolate.

Variants

Some bracts are brightly coloured which aid in the attraction of pollinators, either together with the

perianth The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower. It is a structure that forms an envelope surrounding the sexual organs, consisting of the calyx (sepals) and the corolla (petals) or tepal ...

or instead of it. Examples of this type of bract include those of '' Euphorbia pulcherrima'' (poinsettia) and ''

Bougainvillea ''Bougainvillea'' ( , ) is a genus of thorny ornamental vines, bushes, and trees belonging to the family, Nyctaginaceae. They are native to Brazil, Bolivia, Paraguay, Peru, and Argentina. There are between 4 and 22 species in the genus. The i ...

'': 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 Chaff (; ) is dry, scale-like plant material such as the protective seed casings of cereal grains, the scale-like parts of flowers, or finely chopped straw. Chaff cannot be digested by humans, but it may be fed to livestock, ploughed into soil ...

that is usually removed from

cereal A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize ( Corn). Edible grains from other plant families, ...

grain during

threshing Threshing or thrashing is the process of loosening the edible part of grain (or other crop) from the straw to which it is attached. It is the step in grain preparation after reaping. Threshing does not remove the bran from the grain. History of ...

and winnowing. Bats may detect acoustic signals from dish-shaped bracts such as those of '' Marcgravia evenia''. 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 ''Euphorbia'' is a large and diverse genus of flowering plants, commonly called spurge, in the family (biology), family Euphorbiaceae. Euphorbias range from tiny annual plants to large and long-lived trees, with perhaps the tallest being ''Eu ...

'' species in subgenus ''Lacanthis'' are the cyathophylls. Bracts subtend the cone scales in the seed cones of many

conifer Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

s, and in some cases, such as '' Pseudotsuga'', they extend beyond the cone scales. File:Castilleja levisecta bracts.jpg, Bright yellow bracts of '' Castilleja levisecta'' are more tightly pressed against the stem than bracts of other '' Castilleja'' species. File:Bougainvillea glabra.JPG, Bracts of '' Bougainvillea glabra'', differ in colour from the non-bract leaves, and attract pollinators. File:Banana bract.jpg, Bracts along a

banana A banana is an elongated, edible fruit – botanically a berry – produced by several kinds of large treelike herbaceous flowering plants in the genus '' Musa''. In some countries, cooking bananas are called plantains, distinguishing the ...

flower stalk surround the rows of flowers File:E milii vulcanii ies.jpg, '' Euphorbia milii'' var. ''vulcanii'' cyathia bearing a pair of pinkish cyathophylls. File:Ananas bracteatus var tricolor.jpg, Colourful bracts of '' Ananas bracteatus''. File:Erigeron peregrinus 6287.JPG, The many green

involucral bract In botany, a bract is a modified or specialized leaf, associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves in size, color, shape or texture. They also loo ...

s of '' Erigeron peregrinus'' are linear, loose, taper to a point, about the same length, and help to distinguish this species. File:Blooming Dogwood.jpg,

Dogwood ''Cornus'' is a genus of about 30–60 species of woody plants in the family Cornaceae, commonly known as dogwoods or cornels, which can generally be distinguished by their blossoms, berries, and distinctive bark. Most are deciduous ...

species ''

Cornus florida ''Cornus florida'', the flowering dogwood, is a species of flowering plant, flowering tree in the family Cornaceae native to eastern North America and northern Mexico. An endemic population once spanned from southernmost coastal Maine south to n ...

'' inflorescence showing four large white bracts and central flower cluster. File:2013-05-10 08 26 08 Closeup of pink dogwoods at the Brendan T. Byrne State Forest headquarters.jpg, ''

'' dogwood

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

with pink bracts surrounding small flower cluster. File:豔紅苞鳳梨 20190712192436.jpg, The red bracts of '' Aechmea bracteata''. File:女王鬱金 20190715203108 01.jpg, The pink bracts of '' Curcuma petiolata''. File:火鶴 20190729181532.jpg, The pink bract of a new cultivar: ''

Anthurium andraeanum ''Anthurium andraeanum'' is a flowering plant species in the family Araceae that is native to Colombia and Ecuador. It is a winner of the Royal Horticultural Society's Award of Garden Merit. Names Common names for plants in the genus ''Anthurium ...

'' 'Pink Lady'. File:豔山姜花序總苞 20190508131956.jpg, The inflorescence of '' Alpinia zerumbet'' protected by two bracts before flower bloom. File:地湧金蓮 Musella lasiocarpa 20201028130818 01.jpg, The golden bracts of '' Musella lasiocarpa''.

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

Bracts that appear in a

whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). In nature File:Photograph and axial plane floral diagra ...

subtending an

are collectively called an involucre. An involucre is a common feature beneath the inflorescences of many families like

Apiaceae Apiaceae () or Umbelliferae is a family of mostly aromatic flowering plants named after the type genus ''Apium,'' and commonly known as the celery, carrot, or parsley family, or simply as umbellifers. It is the 16th-largest family of flowering p ...

(carrot family), Asteraceae(sunflower or the daisy family), Dipsacaceae and

Polygonaceae The Polygonaceae are a Family (biology), family of flowering plants known Common name, informally as the knotweed family or smartweed—buckwheat family in the United States. The Botanical name, name is Basionym, based on the genus ''Polygonum'', ...

. Each flower in an inflorescence may have its own whorl of bracts, in this case called an involucel.They can 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 Hornbeams are hardwood trees in the plant genus ''Carpinus'' in the family Betulaceae. Its species occur across much of the temperate regions of the Northern Hemisphere. Common names The common English name ''hornbeam'' derives from the hard ...

'' 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( forms an additional whorl around the calyx of a single flower) is a modification of bracteoles. In other words, the epicalyx is a ''group of bracts resembling a calyx'' or ''bracteoles forming a whorl outer to the calyx''. 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. They are present in the hibiscus family,

Malvaceae Malvaceae (), or the mallows, is a family of flowering plants estimated to contain 244 genera with 4225 known species. Well-known members of economic importance include Theobroma cacao, cacao, Cola (plant), cola, cotton, okra, Hibiscus sabdariffa, ...

. ''

Fragaria ''Fragaria'' () is a genus of flowering plants in the rose family, Rosaceae, commonly known as strawberries for their edible fruits. There are more than 20 described species and many Hybrid plant, hybrids and cultivars. The most common strawberr ...

'' (strawberries) may or may not have an epicalyx.

Spathe

A ''spathe'' is a large bract or a pair of bracts that forms a sheath to enclose the flower cluster of plants such as

palm Palm most commonly refers to: * Palm of the hand, the central region of the front of the hand * Palm plants, of family Arecaceae ** List of Arecaceae genera **Palm oil * Several other plants known as "palm" Palm or Palms may also refer to: Music ...

s, arums, irises,Richard Lynch

crocus ''Crocus'' (; plural: crocuses or croci) is a genus of seasonal flowering plants in the family Iridaceae (iris family) comprising about 100 species of perennial plant, perennials growing from corms. They are low growing plants, whose flower stem ...

esAlex Casha and dayflowers ('' Commelina''). '' Zephyranthes tubispatha'' in the

Amaryllidaceae The Amaryllidaceae are a family of herbaceous, mainly perennial and bulbous (rarely rhizomatous) flowering plants in the monocot order Asparagales. The family takes its name from the genus '' Amaryllis'' and is commonly known as the amaryl ...

derives its specific name from its tubular spathe. In many arums (family

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 ...

), the spathe is petal-like, attracting pollinators to the flowers arranged on a type of spike called a spadix.

References