Asteraceae
Asteraceae or Compositae is a very large and widespread family of flowering plants. The family currently has 32,913 accepted species names, in 1,911 genera and 13 subfamilies. In terms of numbers of species, the Asteraceae are rivaled only by the Orchidaceae.. Nearly all members be…
What is the difference between ray florets and disc floret?
The disc florets are located in the center of the composite flower, and the ray florets bear the outer ring of petal-like structures. Ray florets are sterile, and disc florets have both male and female structures, including a single ovary that develops into a sunflower seed.
What are ray florets of sunflower?
Peripheral florets called ray florets are pistillate or neuter and zygomorphic, whereas disc florets are bisexual and actinomorphic. It is type of racemose inflorescence. A capitulum or head, the characteristic inflorescence of the sunflower family (Asteraceae). One may also ask, what is ray florets of sunflower?
What is a ray flower?
A ray flower is a 3-tipped (3-lobed), strap-shaped, individual flower in the head of some members of the family Asteraceae. Sometimes a ray flower is 2-tipped (2-lobed).
How many disc florets are in a flower head?
A single flower head may have up to two thousand disc florets, each with the potential to develop into a seed. If there are multiple flower heads on the same plant, the number of disc florets per head will be much lower.
What is the difference between a ray floret and a disc floret?
The disc florets are centrally placed and are surrounded by one or two rows of ray florets arranged marginally. The ray florets are female or sterile female flowers. The disc florets are mostly bisexual or staminate.
What is the disc floret?
disc floret in British English or disc flower. noun. any of the small tubular flowers at the centre of the flower head of certain composite plants, such as the daisy. Compare ray floret.
What is the difference between ray and disc flowers in composites?
THREE KINDS OF COMPOSITE FLOWER Heads composed of both disc and ray flowers, with disc flowers tightly packed in the head's "eye," while enlarged ray flowers function as petals radiating outward from the eye.
What is ray floret function?
Ray florets, which are ligulate and zygomorphic, have a showy corolla (petals) and lack stamens. Their primary function is to attract pollinators. The central disc florets, which are radially symmetrical and hermaphroditic, have fertile pollen grains and are mainly required for reproduction [31].
Which ovary has ray florets?
Inferior ovaryAnswer: Option (d) Inferior ovary. Explanation: Ray florets contain inferior ovaries. The inferior ovary is present in epigynous flowers.
What do you mean by florets?
Definition of floret 1 : a small flower especially : one of the small flowers forming the head of a composite plant. 2 : a cluster of flower buds separated from a head especially when used as food broccoli florets.
Are ray florets the same as petals?
While it may look very much like one, a ray flower is not technically a petal as it is a complete flower bearing necessary sexual parts. What we most commonly refer to as a petal (or sometimes tepal) is the usually brightly colored part of the corolla immediately adjacent to but not part of the reproductive organs.
Are ray florets female?
The ray florets are either female, which means they have a pistil, or they are neutral meaning that no sex organs are present or, if present, they are sterile. (2) A slight variation of these are the bilabiate ray florets.
Are Ray flowers petals?
These rays are the petal-like parts, in a comparison of the flower head to an ordinary… …for instance, the outer (or ray) flowers have a well-developed zygomorphic corolla, and the inner (disk) flowers have a small actinomorphic corolla.
What are ray florets of sunflower known as define?
The ray florets of sunflower are known as neuters because it consists neither male or female parts in the flower. If the flower contains any of the small strap-shaped flowers in the head of certain composite plants, such as the daisy is called Ray floret.
In which of these plants disc and ray florets are observed?
Asteraceae species are characterized by having a capitulum, which is a compressed inflorescence consisting of two types of flowers: ray and disc florets.
What is Lemma and Palea?
Palea is the bracelets that grow on a compound flower's receptacle. Lemma is one of the specialized bracts around florets in grass.
Capitulum
The capitulum is a type of racemose inflorescence with a flattened main axis. The capitulum or head is the characteristic of the Asteraceae family. The capitulum contains small, sessile flowers arranged in a centripetal manner on a receptacle.
Ray Florets
Ray florets are strap-shaped. It is 2-3 lobed. They are mostly zygomorphic. Corolla are fused and tubular at the base. The tongue of the corolla is strap-shaped and is known as a ligule or ray. Ray florets are normally sterile. The sterile female flower has a vestigial ovary.
Disc Florets
Disc florets are present in the centre of the head. They are usually actinomorphic. Flowers have tubular corolla. Petals are fused. The top of the petals has apical 4-5 teeth. Disc florets can be unisexual or bisexual. They are normally complete and fertile.
Description
Members of the Asteraceae are mostly herbaceous plants, but some shrubs, vines, and trees (such as Lachanodes arborea) do exist. Asteraceae species are generally easy to distinguish from other plants because of their unique inflorescence and other shared characteristics.
Taxonomy
Compositae, the original name for Asteraceae, were first described in 1740 by Dutch botanist Adriaan van Royen. : 117–118 Traditionally, two subfamilies were recognised: Asteroideae (or Tubuliflorae) and Cichorioideae (or Liguliflorae).
Distribution and habitat
Asteraceae species have a widespread distribution, from subpolar to tropical regions in a wide variety of habitats. Most occur in hot desert and cold or hot semi-desert climates, and they are found on every continent but Antarctica.
Ecology
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Uses
The twining succulent, Senecio angulatus, is used for its cut flowers, despite being an invasive weed in some places, such as Victoria, Australia and New Zealand.
Bibliography
Funk, Vicki A.; Susanna, A.; Stuessy, T. F.; Bayer, R. J., eds. (2009). Systematics, Evolution, and Biogeography of Compositae. Vienna: International Association for Plant Taxonomy. ISBN 978-3-9501754-3-1.(Available here at Internet Archive)
