Perianth in the context of "Actinomorphic"

A sepal (/ˈsɛpəl, ˈsiːpəl/) is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom.

Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the corolla. Petals are usually surrounded by an outer whorl 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 coloured tepals. Since they include Liliales, an alternative name is lilioid monocots.

Although petals are usually the most conspicuous parts of animal-pollinated flowers, wind-pollinated species, such as the grasses, either have very small petals or lack them entirely (apetalous).

The Amaryllidaceae are a family of herbaceous, mainly perennial and bulbous (rarely rhizomatous) flowering plants in the monocot order Asparagales. The family takes its name from the genus Amaryllis and is commonly known as the amaryllis family. The leaves are usually linear, and the flowers are usually bisexual and symmetrical, arranged in umbels on the stem. The petals and sepals are undifferentiated as tepals, which may be fused at the base into a floral tube. Some also display a corona. Allyl sulfide compounds produce the characteristic odour of the onion subfamily (Allioideae).

The family, which was originally created in 1805, now contains about 1600 species, divided into 71 genera, 17 tribes and three subfamilies, the Agapanthoideae (Agapanthus), Allioideae (onions, garlic and chives) and Amaryllidoideae (amaryllis, daffodils, snowdrops). Over time, it has seen much reorganisation and at various times was combined with the related Liliaceae. Since 2009, a very broad view has prevailed based on phylogenetics, and including a number of other former families.

A tepal is one of the outer parts of a flower (collectively the perianth). 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 (i.e. of very similar appearance), 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 (as in Lilium). The term was proposed by Augustin Pyramus de Candolle in 1827 and was constructed by analogy with the terms "petal" and "sepal". (De Candolle used the term perigonium or perigone for the tepals collectively; the term is since used as a synonym for perianth.)

Anthesis is the period during which a flower is fully open and functional. It may also refer to the onset of that period.

The onset of anthesis is spectacular in some species. In Banksia species, for example, anthesis involves the extension of the style far beyond the upper perianth parts. Anthesis of flowers is sequential within an inflorescence, so when the style and perianth are different colours, the result is a striking colour change that gradually sweeps along the inflorescence.

Zelkova (from the Georgian dzelkva, 'stone pillar') is a genus of six species of deciduous trees in the elm family Ulmaceae, native to southern Europe, and southwest and eastern Asia. They vary in size from shrubs (Z. sicula) to large trees up to 35 m (115 ft) tall (Z. carpinifolia). The bark is smooth, dark brown. Unlike elms, the branchlets are never corky or winged. The leaves are alternate, with serrated margins, and (unlike the related elms) a symmetrical base to the leaf blade. The leaves are in two distinct rows; they have pinnate venation and each vein extends to the leaf margin, where it terminates in a tooth. There are two stipules at each node, though these are caducous (shed early), leaving a pair of scars at the leaf base. Zelkova is polygamous. Staminate flowers are clustered in the lower leaf axils of young branchlets; the perianth is campanulate, with four to six (to seven) lobes, and the stamens are short. Pistillate and hermaphrodite flowers are solitary, or rarely in clusters of two to four, in the upper leaf axils of young branchlets. The fruit is a dry, nut-like drupe with a dorsal keel, produced singly in the leaf axils. The perianth and stigma are persistent.

In botany, adnation is the fusion of two or more whorls of a flower, e.g. stamens to petals, within angiosperms (flowering plants). This is in contrast to connation, the fusion among a single whorl.