Sessility (botany)

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The perennial wildflower Trillium cernuum possesses three leaves that are sessile at the top of the stem. Trillium cernuum 1-eheep (5098010914).jpg
The perennial wildflower Trillium cernuum possesses three leaves that are sessile at the top of the stem.

In botany, sessility (meaning "sitting", in the sense of "resting on the surface") is a characteristic of plant organs such as flowers or leaves that have no stalk. [1] [2] Plant parts can also be described as subsessile, that is, not completely sessile.

A sessile flower is one that lacks a pedicel (flower stalk). A flower that is not sessile is pedicellate. For example, the genus Trillium is partitioned into multiple subgenera, the sessile-flowered trilliums (Trillium subgen. Sessilia) and the pedicellate-flowered trilliums.

The term "sessility" is also used in mycology to describe a fungal fruit body that is attached to or seated directly on the surface of the substrate, lacking a supporting stipe or pedicel. [3]

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

Trillium is a genus of about fifty flowering plant species in the family Melanthiaceae. Trillium species are native to temperate regions of North America and Asia, with the greatest diversity of species found in the southern Appalachian Mountains in the southeastern United States.

<i>Trillium chloropetalum</i> Species of flowering plant

Trillium chloropetalum, also known as giant trillium, giant wakerobin, or common trillium, is a species of flowering plant in the family Melanthiaceae. It is endemic to the western U.S. state of California, being especially frequent in and around the San Francisco Bay Area.

<i>Trillium erectum</i> Species of flowering plant

Trillium erectum, the red trillium, also known as wake robin, purple trillium, bethroot, or stinking benjamin, is a species of flowering plant in the family Melanthiaceae. The plant takes its common name "wake robin" by analogy with the European robin, which has a red breast heralding spring. Likewise Trillium erectum is a spring ephemeral plant whose life-cycle is synchronized with that of the forests in which it lives. It is native to the eastern United States and eastern Canada from northern Georgia to Quebec and New Brunswick.

<span class="mw-page-title-main">Panicle</span> Term used in botany to describe a branching of flower heads

A panicle is a much-branched inflorescence. Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers be pedicellate. The branches of a panicle are often racemes. A panicle may have determinate or indeterminate growth.

<span class="mw-page-title-main">Raceme</span> Unbranched, indeterminate type of inflorescence bearing pedicellate flowers along its axis

A raceme or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the shoot grows in height, with no predetermined growth limit. Examples of racemes occur on mustard, radish, and orchid plants.

<span class="mw-page-title-main">Peduncle (botany)</span> Stalk of a plant bearing an inflorescence or solitary flower

In botany, a peduncle is a stalk supporting an inflorescence or a solitary flower, or, after fecundation, an infructescence or a solitary fruit. The peduncle sometimes has bracts at nodes. The main axis of an inflorescence above the peduncle is the rachis. There are no flowers on the peduncle but there are flowers on the rachis.

<i>Trillium luteum</i> Species of plant

Trillium luteum, the yellow trillium or yellow wakerobin, is a species of flowering plant in the bunchflower family Melanthiaceae. It is a member of the Trillium cuneatum complex, a closely related group of sessile-flowered trilliums. The species is endemic to the southeastern United States, especially in and around the Great Smoky Mountains of eastern Tennessee and western North Carolina.

<i>Trillium undulatum</i> Species of flowering plant

Trillium undulatum, commonly called painted trillium, painted lady, or trille ondulé in French, is a species of flowering plant in the bunchflower family Melanthiaceae. It is also known as smiling wake robin or striped wake-robin. The specific epithet undulatum means "wavy", which refers to the wavy edges of the flower petals. The plant is found from Ontario in the north to northern Georgia in the south and from Michigan in the west to Nova Scotia in the east.

<i>Trillium cuneatum</i> Species of flowering plant

Trillium cuneatum, the little sweet betsy, also known as whip-poor-will flower, large toadshade, purple toadshade, and bloody butcher, is a species of flowering plant in the family Melanthiaceae. It is a member of the Trillium cuneatum complex, a subgroup of the sessile-flowered trilliums. It is native to the southeastern United States but is especially common in a region that extends from southern Kentucky through central Tennessee to northern Alabama. In its native habitat, this perennial plant flowers from early March to late April. It is the largest of the eastern sessile-flowered trilliums.

<i>Trillium sessile</i> Species of flowering plant

Trillium sessile is a species of flowering plant in the bunchflower family Melanthiaceae. The specific epithet sessile means "attached without a distinct stalk", an apparent reference to its stalkless flower. It is commonly known as toadshade or toad trillium. It is also called sessile trillium or sessile-flowered wake-robin, however it is not the only member of the genus with a sessile flower.

<i>Trillium cernuum</i> Species of flowering plant

Trillium cernuum is a species of flowering plant in the bunchflower family Melanthiaceae. The specific epithet cernuum means "drooping, curving forwards, facing downwards", a distinctive habit of its flower. It is commonly called nodding trillium or nodding wakerobin since the flower is invariably found nodding beneath the leaves. It is sometimes referred to as the northern nodding trillium to distinguish from Trillium rugelii, a similar nodding species native to the southern Appalachian Mountains. It is also called the whip-poor-will flower since presumably its bloom coincides with the spring arrival of the migrating bird with the same name.

<span class="mw-page-title-main">Pedicel (botany)</span> Structure connecting flowers or fruit to the main stem of a plant

In botany, a pedicel is a stem that attaches a single flower to the inflorescence. Such inflorescences are described as pedicellate.

<i>Trillium stamineum</i> Species of flowering plant

Trillium stamineum, the twisted trillium, also known as the Blue Ridge wakerobin, is a species of flowering plant in the family Melanthiaceae. It is native to the southeastern United States, in Alabama, Mississippi and Tennessee. Its natural habitat is calcareous woodlands.

A peduncle is an elongated stalk of tissue. Sessility is the state of not having a peduncle; a sessile mass or structure lacks a stalk.

<i>Trillium sulcatum</i> Species of flowering plant

Trillium sulcatum is a species of flowering plant in the bunchflower family Melanthiaceae. It is a member of the Erectum group, a group of species typified by Trillium erectum. The specific name sulcatum means "furrowed, grooved, or sulcate", which describes the tips of the sepals. It is most abundant on the Cumberland Plateau in central Tennessee and eastern Kentucky where it blooms in April and May. The species is commonly known as the southern red trillium or furrowed wakerobin.

<i>Trillium albidum</i> Species of flowering plant

Trillium albidum is a species of flowering plant in the bunchflower family Melanthiaceae. It is the only trillium characterized by a stalkless white flower. The species is endemic to the western United States, ranging from central California through Oregon to southwestern Washington. In the San Francisco Bay Area, it is often confused with a white-flowered form of Trillium chloropetalum. In northern Oregon and southwestern Washington, it has a smaller, less conspicuous flower.

<i>Trillium petiolatum</i> Species of flowering plant

Trillium petiolatum, the Idaho trillium, also known as the long-petioled trillium or round-leaved trillium, is a species of flowering plant in the family Melanthiaceae. It is native to the northwestern United States, in Idaho, Oregon, and Washington. Its type specimen was gathered by Meriwether Lewis during the return trip of the Lewis and Clark Expedition in 1806.

<i>Trillium kurabayashii</i> Species of flowering plant

Trillium kurabayashii is a species of flowering plant in the bunchflower family Melanthiaceae. The species is endemic to the western United States, occurring in extreme southwestern Oregon, northwestern California, and the Sierra Nevada of northern California. It was first described by John Daniel Freeman in 1975. The specific epithet kurabayashii honors Masataka Kurabayashi, a Japanese cytologist and population geneticist who first postulated the taxon’s existence. It is commonly known as the giant purple wakerobin, a reference to its conspicuously large, dark purple-red flower, one of the largest of any sessile-flowered trillium.

<i>Trillium maculatum</i> Species of flowering plant

Trillium maculatum, the spotted wakerobin or spotted trillium, is a species of flowering plant in the family Melanthiaceae. It is a member of the Trillium cuneatum complex, a closely related group of sessile-flowered trilliums. The species is endemic to the southeastern United States, ranging across Alabama, Georgia, South Carolina, and northern Florida.

Trillium viride, commonly called the wood wakerobin, is a species of flowering plant in the family Melanthiaceae. It is found in the central United States, in certain parts of Missouri and Illinois. The specific epithet viride means "youthful" or "fresh-green", an apparent reference to the color of the plant's flower petals. For this reason, it is also called the green trillium, not to be confused with other green-flowered trilliums such as T. viridescens and the green form of T. sessile, both of which are found in Missouri.

References

  1. Beentje, H.; Williamson, J. (2010). The Kew Plant Glossary: an Illustrated Dictionary of Plant Terms. Royal Botanic Gardens, Kew: Kew Publishing.
  2. Hickey, M.; King, C. (2001). The Cambridge Illustrated Glossary of Botanical Terms. Cambridge University Press.
  3. Ulloa, Miguel; Halin, Richard T. (2012). Illustrated Dictionary of Mycology (2nd ed.). St. Paul, Minnesota: The American Phytopathological Society. p. 575. ISBN   978-0-89054-400-6.