sepal

(noun)

a part of an angiosperm, and one of the component parts of the calyx; collectively the sepals are called the calyx (plural calyces), the outermost whorl of parts that form a flower

Related Terms

Examples of sepal in the following topics:

  • Angiosperm Flowers

    • Although they vary greatly in appearance, all flowers contain the same structures: sepals, petals, carpels, and stamens.
    • A whorl of sepals (collectively called the calyx) is located at the base of the peduncle and encloses the unopened floral bud.
    • Sepals are usually photosynthetic organs, although there are some exceptions.
    • For example, the corolla in lilies and tulips consists of three sepals and three petals that look virtually identical.
    • Sepals and petals together form the perianth.

  • Genetic Control of Flowers

    • The ABC model of flower development was first developed to describe the collection of genetic mechanisms that establish floral organ identity in the Rosids and the Asterids; both species have four verticils (sepals, petals, stamens and carpels), which are defined by the differential expression of a number of homeotic genes present in each verticil.
    • In the first floral whorl only A-genes are expressed, leading to the formation of sepals.
    • For example, when there is a loss of B-gene function, mutant flowers are produced with sepals in the first whorl as usual, but also in the second whorl instead of the normal petal formation.
    • Class A genes (blue) affect sepals and petals, class B genes (yellow) affect petals and stamens, class C genes (red) affect stamens and carpels.

  • Data basics exercises

    • Sir Ronald Aylmer Fisher was an English statistician, evolutionary biologist, and geneticist who worked on a data set that contained sepal length and width, and petal length and width from three species of iris flowers (setosa, versicolor and virginica).
    • (b) Four continuous numerical variables: sepal length, sepal width, petal length, and petal width.
    • Fisher used irises - based on species, including their sepal length and width, and petal length and width - as his data set.

  • Sexual Reproduction in Angiosperms

    • The outermost whorl of the flower has green, leafy structures known as sepals, which are collectively called the calyx, and help to protect the unopened bud.
    • The number of sepals and petals varies depending on whether the plant is a monocot or dicot.

  • Introduction to data solutions

    • (b) Four continuous numerical variables: sepal length, sepal width, petal length, and petal width.