Tepal

Diagram that shows the parts of a mature flower. In this example, the peranto is separated into chalice (sepals) and corolla (peals).

The tepal is the segment or unit of the perianths in which the corolla and the calyx are not clearly differentiated, as in the tulip or the onion.

More specifically, a tepal is the flowering part of a plant in the magnolia family, the Magnoliaceae, and various other primitive flowering plants, such as the Amborellaceae. It corresponds to the sepals and petals in the flowers of other plants with double or compound perianths, but unlike these, all the tepals are of the same shape and color, there being almost no difference, without sepals that serve as protection for the developing bud., nor larger petals that attract insects.

Origin

A flower of Lilium which shows the six teapals: the three exteriors are sepals and the three interiors are petals.

Undifferentiated tepals are believed to be the ancestral condition of Angiospermae, or flowering plants. For example, Amborella, which is believed to have diverged earlier in the evolution of flowering plants, has flowers with undifferentiated tepals. Thus, distinct petals and sepals would have arisen by differentiation, probably in response to animal pollination. In typical modern flowers, the outer or enveloping whorl of organs forms sepals, specialized to protect the flower bud as it develops, while the inner whorl forms petals that attract pollinators.

Tepals made up of similar sepals and petals are common in monocots, particularly lilioid monocots. In tulips, for example, the first and second whorls contain petal-like structures. These are fused at the base to form a large and striking six-part structure (the perianth). In lilies, the organs in the first whorl are separate from the second, but they all look similar, so all the conspicuous parts are often called tepals. When sepals and petals can be distinguished in principle, the use of the term "tepal" not always consistent; some authors will refer to "sepals and petals", while others use "tepals" in the same context.^{[citation required]}

In some plants, the flowers have no petals and all the tepals are sepals modified to look like petals. These organs are described as petaloid, for example, the sepals of hellebores. When undifferentiated tepals resemble petals, they are also called petaloids, as in petaloid monocots, orders of monocots with brightly colored tepals. Since they include Liliales, an alternate name is lilioid monocots.^{[citation needed]}

Properties and form

The terms used in the description of the tepals are: pubescent (with dense, fine, short and soft hairs, downy), puberulent (minutely pubescent, hairs barely visible to the naked eye) and puberulous (dense cover of very short hairs and smooth). The shape of the tepals is described in terms similar to those used for the leaves (see Leaf morphology).

Gallery

• Flowers with teapals
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  Flowers of Magnolia × alba. Tepals are shown in several stages of development.

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  Tépalos de Magnolia × wieseneri

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  A Helleborus flower that shows the petaloid sepals.

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  A flower of Sternbergia lutea which shows the two tepal verticils.

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  A flower of Tulip showing the teapals in the form of petal.

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  ClothesBlandfordia nobilis, another monocothylene lilioid.