Whorl (botany)

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Photograph and axial plane floral diagram of Friesodielsia desmoides, showing the whorled pattern of multiple concentric objects. Photograph and axial plane floral diagram of Friesodielsia desmoides.jpg
Photograph and axial plane floral diagram of Friesodielsia desmoides , showing the whorled pattern of multiple concentric objects.
Leaf whorls on a herbaceous Lilium michiganense MichiganLilyStem.jpg
Leaf whorls on a herbaceous Lilium michiganense
Leaf whorls on a woody tree, Brabejum stellatifolium Brabejum stellatifolium - new growth.JPG
Leaf whorls on a woody tree, Brabejum stellatifolium

In botany, a whorl or verticil is a whorled arrangement of leaves, sepals, petals, stamens, or carpels that radiate from a single point and surround or wrap around the stem or stalk. [1] [2] A leaf whorl consists of at least three elements; a pair of opposite leaves is not called a whorl.

For leaves to grow in whorls is fairly rare except in plant species with very short internodes and some other genera ( Galium , Nerium , Elodea etc.). Leaf whorls occur in some trees such as Brabejum stellatifolium and other species in the family Proteaceae (e.g., in the genus Banksia ). In plants such as these, crowded internodes within the leaf whorls alternate with long internodes between the whorls.

The morphology of most flowers (called cyclic flowers) is based on four types of whorls:

  1. The calyx: zero or more whorls of sepals at the base
  2. The corolla: zero or more whorls of petals above the calyx
  3. The androecium: zero or more whorls of stamens, each comprising a filament and an anther
  4. The gynoecium: zero or more whorls of carpels, each consisting of an ovary, a style, and a stigma

A flower lacking any of these floral structures is said to be incomplete or imperfect. [3] Not all flowers consist of whorls since the parts may instead be spirally arranged, as in the family Magnoliaceae.

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<span class="mw-page-title-main">Hypanthium</span> Structure in angiosperms where basal portions form a cup-shaped tube

In angiosperms, a hypanthium or floral cup is a structure where basal portions of the calyx, the corolla, and the stamens form a cup-shaped tube. It is sometimes called a floral tube, a term that is also used for corolla tube and calyx tube. It often contains the nectaries of the plant. It is present in many plant families, although varies in structural dimensions and appearance. This differentiation between the hypanthium in particular species is useful for identification. Some geometric forms are obconic shapes as in toyon, whereas some are saucer-shaped as in Mitella caulescens.

<span class="mw-page-title-main">Petal</span> Part of most types of flower

Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the corolla. Petals are usually accompanied by another set of modified leaves called sepals, that collectively form the calyx and lie just beneath the corolla. The calyx and the corolla together make up the perianth, the non-reproductive portion of a flower. 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 colored tepals. Since they include Liliales, an alternative name is lilioid monocots.

<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">Sepal</span> Any of the separate parts of the calyx of a flower (excluding the bracts), usually green

A sepal is a part of the flower of angiosperms. Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom.

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

Lythraceae is a family of flowering plants, including 32 genera, with about 620 species of herbs, shrubs, and trees. The larger genera include Cuphea, Lagerstroemia (56), Nesaea (50), Rotala (45), and Lythrum (35). It also includes the members of the former families of the pomegranate and of the water caltrop. Lythraceae has a worldwide distribution, with most species in the tropics, but ranging into temperate climate regions as well.

<span class="mw-page-title-main">Tepal</span> One of the outer parts of a flower

A tepal is one of the outer parts of a flower. 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, 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. The term was first proposed by Augustin Pyramus de Candolle in 1827 and was constructed by analogy with the terms "petal" and "sepal".

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

The Canellaceae are a family of flowering plants in the order Canellales. The order includes only one other family, the Winteraceae. Canellaceae is native to the Afrotropical and Neotropical realms. They are small to medium trees, rarely shrubs, evergreen and aromatic. The flowers and fruit are often red.

<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">Plant reproductive morphology</span> Parts of plant enabling sexual reproduction

Plant reproductive morphology is the study of the physical form and structure of those parts of plants directly or indirectly concerned with sexual reproduction.

<span class="mw-page-title-main">Alismataceae</span> Family of flowering plants comprising the water-plantains

The water-plantains (Alismataceae) are a family of flowering plants, comprising 20 genera and 119 species. The family has a cosmopolitan distribution, with the greatest number of species in temperate regions of the Northern Hemisphere. Most of the species are herbaceous aquatic plants growing in marshes and ponds.

<span class="mw-page-title-main">Perianth</span> Collective term for the sepals and petals, or either of them if one is absent

The perianth is the non-reproductive part of the flower, and structure that forms an envelope surrounding the sexual organs, consisting of the calyx (sepals) and the corolla (petals) or tepals when called a perigone. The term perianth is derived from Greek περί and άνθος, while perigonium is derived from περί and γόνος . In the mosses and liverworts (Marchantiophyta), the perianth is the sterile tubelike tissue that surrounds the female reproductive structure.

<span class="mw-page-title-main">Gynoecium</span> Female organs of a flower

Gynoecium is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of pistils and is typically surrounded by the pollen-producing reproductive organs, the stamens, collectively called the androecium. The gynoecium is often referred to as the "female" portion of the flower, although rather than directly producing female gametes, the gynoecium produces megaspores, each of which develops into a female gametophyte which then produces egg cells.

Merosity refers to the number of component parts in a distinct whorl of a plant structure. The term is most commonly used in the context of a flower where it refers to the number of sepals in a whorl of the calyx, the number of petals in a whorl of the corolla, the number of stamens in a whorl of the androecium, or the number of carpels in a whorl of the gynoecium. The term may also be used to refer to the number of leaves in a leaf whorl.

This page provides a glossary of plant morphology. Botanists and other biologists who study plant morphology use a number of different terms to classify and identify plant organs and parts that can be observed using no more than a handheld magnifying lens. This page provides help in understanding the numerous other pages describing plants by their various taxa. The accompanying page—Plant morphology—provides an overview of the science of the external form of plants. There is also an alphabetical list: Glossary of botanical terms. In contrast, this page deals with botanical terms in a systematic manner, with some illustrations, and organized by plant anatomy and function in plant physiology.

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.

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

Lepidobotryaceae is a family of plants in the order Celastrales. It contains only two species: Lepidobotrys staudtii and Ruptiliocarpon caracolito.

A cyclic flower is a flower type formed out of a series of whorls; sets of identical organs attached around the axis at the same point. Most flowers consist of a single whorl of sepals termed a calyx; a single whorl of petals termed a corolla; one or more whorls of stamens ; and a single whorl of carpels termed the gynoecium. This is a cyclic arrangement.

<span class="mw-page-title-main">Connation</span> Term in botanical morphology

Connation in plants is the developmental fusion of organs of the same type, for example, petals to one another to form a tubular corolla. This is in contrast to adnation, the fusion of dissimilar organs. Such organs are described as connate or adnate, respectively. When like organs that are usually well separated are placed next to each other, but not actually connected, they are described as connivent.

<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.

Sedum sekiteiense Yamamoto is a Taiwan-endemic species of the family Crassulaceae in the Sedum genus. It is also one of the few wild plants named after Shiding. The species was first published by Yoshimatsu Yamamoto in 1934 in the Supplementa Iconum Plantarum Formosanarum. Although its taxonomic status has been stable, little is known about its ecological habits due to its rarity, limited distribution, and habitats that are often located on steep and inaccessible cliffs that are difficult to observe. The species is classified as “Vulnerable (VU)” in “The Red List of Vascular Plants of Taiwan, 2017.”

References

  1. "whorl". thedictionary. Retrieved 19 August 2012.
  2. Lindley, John. A Glossary of Technical Terms Used in Botany , p.100, Bradbury and Evans, London, 1848.
  3. Beentje, H.; Williamson, J. (2010). The Kew Plant Glossary: an Illustrated Dictionary of Plant Terms. Royal Botanic Gardens, Kew: Kew Publishing.