The family Asteraceae, with the original name Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae were first described in the year 1740. The number of species in Asteraceae is rivaled only by the Orchidaceae, and which is the larger family is unclear as the quantity of extant species in each family is unknown.
In botany, a seed is a plant embryo and food reserve enclosed in a protective outer covering called a seed coat (testa). More generally, the term "seed" means anything that can be sown, which may include seed and husk or tuber. Seeds are the product of the ripened ovule, after the embryo sac is fertilized by sperm from pollen, forming a zygote. The embryo within a seed develops from the zygote and grows within the mother plant to a certain size before growth is halted.
Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance's molecules, adsorbing substances can become physically changed, e.g. changing in volume, boiling point, viscosity or some other physical characteristic or property of the substance. For example, a finely dispersed hygroscopic powder, such as a salt, may become clumpy over time due to collection of moisture from the surrounding environment.
An achene, also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent. Achenes contain a single seed that nearly fills the pericarp, but does not adhere to it. In many species, what is called the "seed" is an achene, a fruit containing the seed. The seed-like appearance is owed to the hardening of the fruit wall (pericarp), which encloses the solitary seed so closely as to seem like a seed coat.
Cirsium vulgare, the spear thistle, bull thistle, or common thistle, is a species of the Asteraceae genus Cirsium, native throughout most of Europe, Western Asia, and northwestern Africa. It is also naturalised in North America, Africa, and Australia and is an invasive weed in some areas. It is the national flower of Scotland.
A vortex ring, also called a toroidal vortex, is a torus-shaped vortex in a fluid; that is, a region where the fluid mostly spins around an imaginary axis line that forms a closed loop. The dominant flow in a vortex ring is said to be toroidal, more precisely poloidal.
In spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant. Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors, such as the wind, and living (biotic) vectors such as birds. Seeds can be dispersed away from the parent plant individually or collectively, as well as dispersed in both space and time. The patterns of seed dispersal are determined in large part by the dispersal mechanism and this has important implications for the demographic and genetic structure of plant populations, as well as migration patterns and species interactions. There are five main modes of seed dispersal: gravity, wind, ballistic, water, and by animals. Some plants are serotinous and only disperse their seeds in response to an environmental stimulus. These modes are typically inferred based on adaptations, such as wings or fleshy fruit. However, this simplified view may ignore complexity in dispersal. Plants can disperse via modes without possessing the typical associated adaptations and plant traits may be multifunctional.
A tumbleweed is a structural part of the above-ground anatomy of a number of species of plants. It is a diaspore that, once mature and dry, detaches from its root or stem and rolls due to the force of the wind. In most such species, the tumbleweed is in effect the entire plant apart from the root system, but in other plants, a hollow fruit or inflorescence might detach instead. Xerophyte tumbleweed species occur most commonly in steppe and arid ecosystems, where frequent wind and the open environment permit rolling without prohibitive obstruction.
In botany, an awn is either a hair- or bristle-like appendage on a larger structure, or in the case of the Asteraceae, a stiff needle-like element of the pappus.
Taraxacum officinale, the dandelion or commondandelion, is a herbaceous perennial flowering plant in the daisy family Asteraceae. The common dandelion is well known for its yellow flower heads that turn into round balls of many silver-tufted fruits that disperse in the wind. These balls are called "clocks" in both British and American English. The name "blowball" is also used.
Olearia hectorii is a species of flowering plant in the daisy family Asteraceae. Its common names include deciduous tree daisy and Hector's tree daisy. It is endemic to New Zealand, where it is nationally endangered.
Layia carnosa is a species of flowering plant in the family Asteraceae known by the common name beach tidytips, or beach layia. It is endemic to California, where it lives in coastal habitat. It is known from several areas of mostly fragmented or relict sand dune habitat, and it was listed as an endangered species in California. On March 31, 2022, the category was changed from endangered species to threatened species by the US Department of the Interior Fish and Wildlife Service.
Taraxacum is a large genus of flowering plants in the family Asteraceae, which consists of species commonly known as dandelions. The scientific and hobby study of the genus is known as taraxacology. The genus is native to Eurasia and North America, but the two most commonplace species worldwide, T. officinale and T. erythrospermum, were introduced from Europe into North America, where they now propagate as wildflowers. The plant thrives in temperate regions and can be found in yards, gardens, sides of roads, among crops, and in many other habitats. Both species are edible in their entirety and have a long history of consumption. The common name dandelion is also given to specific members of the genus.
Taraxacum albidum is a species of dandelion that grows in eastern Eurasia. A member of the Asteraceae, it is a perennial herbaceous plant native to southern Japan.
Gymnarrhena is a deviant genus of plants in the family Asteraceae, with only one known species, Gymnarrhena micrantha. It is native to North Africa and the Middle East, as far east as Balochistan. Together with the very different Cavea tanguensis it constitutes the tribe Gymnarrheneae, and in the subfamily Gymnarrhenoideae.
In agriculture, shattering is the dispersal of a crop's seeds upon their becoming ripe. From an agricultural perspective this is generally an undesirable process, and in the history of crop domestication several important advances have involved a mutation in a crop plant that reduced shattering—instead of the seeds being dispersed as soon as they were ripe, the mutant plants retained the seeds for longer, which made harvesting much more effective. Non-shattering phenotype is one of the prerequisites for plant breeding especially when introgressing valuable traits from wild varieties of domesticated crops.
Catananche lutea, is a woolly annual plant, in the family Asteraceae, with most leaves in a basal rosette, and some smaller leaves on the stems at the base of the branches. Seated horizontal flowerheads develop early on under the rosette leaves. Later, not or sparingly branching erect stems grow to 8–40 cm high, carrying solitary flowerheads at their tips with a papery involucre whitish to beige, reaching beyond the yellow ligulate florets. Flowers are present between April and June. This plant is unique for the five different types of seed it develops, few larger seeds from the basal flowerheads, which remain in the soil, and smaller seeds from the flowerheads above ground that may be spread by the wind or remain in the flowerhead when it breaks from the dead plant. This phenomenon is known as amphicarpy. The seeds germinate immediately, but in one type, germination is postponed. It naturally occurs around the Mediterranean. Sources in English sometimes refer to this species as yellow succory.
In botanical terminology, a phyllary, also known an involucral bract or tegule, is a single bract of the involucre of a composite flower. The involucre is the grouping of bracts together. Phyllaries are reduced leaf-like structures that form one or more whorls immediately below a flower head.
Senecio quadridentatus is native to Australia and New Zealand. In New Zealand it is known by its Māori name pahokoraka or pekapeka. Senecio quadridentatus is an annual or perennial herbaceous flowering plant in the family Asteraceae. It is also known as Erechtites quadridentata Labill by the synonyms.
Taraxacum ceratophorum, also known as the horned dandelion, is a species of flowering plant within the genus Taraxacum and family Asteraceae. This alpine species has a preference for mountainous habitat, where it can be found growing at elevations up to 3000 meters above sea level. It is native to a large portion of the Northern Hemisphere, inhabiting various countries within Asia, Europe and North America.
