The stigma (: stigmas or stigmata) is the receptive tip of a

carpel Gynoecium (; ; : gynoecia) 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 (one or more ...

, or of several fused carpels, in the

gynoecium Gynoecium (; ; : gynoecia) 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 (botany), whorl of a flower; it consists ...

of 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 ...

Description

The stigma, together with the

style Style, or styles may refer to: Film and television * ''Style'' (2001 film), a Hindi film starring Sharman Joshi, Riya Sen, Sahil Khan and Shilpi Mudgal * ''Style'' (2002 film), a Tamil drama film * ''Style'' (2004 film), a Burmese film * '' ...

and

ovary The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/ oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are end ...

(typically called the stigma-style-ovary system) comprises the

pistil Gynoecium (; ; : gynoecia) 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 (botany), whorl of a flower; it consists ...

, which is part of the

or female reproductive organ of a plant. The stigma itself forms the distal portion of the style, or stylodia, and is composed of , the cells of which are receptive to pollen. These may be restricted to the apex of the style or, especially in wind pollinated species, cover a wide surface. The stigma receives

pollen Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...

and it is on the stigma that the pollen grain germinates. Often sticky, the stigma is adapted in various ways to catch and trap pollen with various hairs, flaps, or sculpturings. The pollen may be captured from the air (wind-borne pollen,

anemophily Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including grasses, sedges, and rushes. Other common anemophilous ...

), from visiting insects or other animals ( biotic pollination), or in rare cases from surrounding water ( hydrophily). Stigma can vary from long and slender to globe shaped to feathery. Pollen is typically highly desiccated when it leaves an anther. Stigma have been shown to assist in the rehydration of pollen and in promoting germination of the pollen tube. Stigma also ensure proper adhesion of the correct species of pollen. Stigma can play an active role in pollen discrimination and some self-incompatibility reactions, that reject pollen from the same or genetically similar plants, involve interaction between the stigma and the surface of the pollen grain.

Shape

The stigma is often split into lobes, e.g. trifid (three lobed), and may resemble the head of a pin (capitate), or come to a point (punctiform). The shape of the stigma may vary considerably: Cornsilk 7091

Style

The style is a narrow upward extension of the ovary, connecting it to the stigmatic papillae. Occasionally, it may be absent, in which case the stigma is described as sessile. Styles are generally tube-like—either long or short. The style can be open (containing few or no cells in the central portion) with a central canal which may be filled with mucilage. Alternatively the style may be closed (densely packed with cells throughout). Most syncarpous monocots and some eudicots have open styles, while many syncarpous eudicots and grasses have closed (solid) styles containing specialised secretory transmitting tissue, linking the stigma to the centre of the ovary. This forms a nutrient rich tract for pollen tube growth. Where there are more than one carpel to the pistil, each may have a separate style-like stylodium, or share a common style. In irises and others in the family Iridaceae, the style divides into three petal-like (petaloid) ''style branches'' (sometimes also referred to as 'stylodia'), almost to the base of the style and is called a . These are flaps of tissue, running from the perianth tube above the sepal. The stigma is a rim or edge on the underside of the branch, near the end lobes. Style branches also appear on '' Dietes'', '' Pardanthopsis'' and most species of '' Moraea''.Klaus Kubitzki (Editor) In ''

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 ...

'', there are three divided style branches, creating a tube.Michael Hickey, Clive King '' Hesperantha'' has a spreading style branch. Alternatively, the style may be lobed rather than branched. '' Gladiolus'' has a bi-lobed style branch (bilobate). '' Freesia'', '' Lapeirousia'', '' Romulea'', '' Savannosiphon'' and '' Watsonia'' have bifurcated (two branched) and recurved style branches.

References

Citations

Sources

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External links

Stigma shape and size - English labels

Terminal versus gynobasic style
Images
Gynobasic
Diagram {{botany Plant reproductive system Plant morphology Plant sexuality