Asterales is an order of dicotyledonous flowering plants that includes the large family Asteraceae known for composite flowers made of florets, and ten families related to the Asteraceae. While asterids in general are characterized by fused petals, composite flowers consisting of many florets create the false appearance of separate petals.
Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae. Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of flagella or centrioles, except in the gametes, and a unique method of cell division involving the formation of a cell plate or phragmoplast that separates the new daughter cells.
Xylem is one of the two types of transport tissue in vascular plants, the other being phloem. The basic function of the xylem is to transport water from roots to stems and leaves, but it also transports nutrients. The word xylem is derived from the Ancient Greek word ξύλον (xylon), meaning "wood"; the best-known xylem tissue is wood, though it is found throughout a plant. The term was introduced by Carl Nägeli in 1858.
Vascular plants, also called tracheophytes or collectively tracheophyta, form a large group of land plants that have lignified tissues for conducting water and minerals throughout the plant. They also have a specialized non-lignified tissue to conduct products of photosynthesis. Vascular plants include the clubmosses, horsetails, ferns, gymnosperms, and angiosperms. Scientific names for the group include Tracheophyta, Tracheobionta and Equisetopsida sensu lato. Some early land plants had less developed vascular tissue; the term eutracheophyte has been used for all other vascular plants, including all living ones.
Gnetophyta is a division of plants, grouped within the gymnosperms, that consists of some 70 species across the three relict genera: Gnetum, Welwitschia, and Ephedra. The earliest unambiguous records of the group date to the Jurassic, and they achieved their highest diversity during the Early Cretaceous. The primary difference between gnetophytes and other gymnosperms is the presence of vessel elements, a system of small tubes (xylem) that transport water within the plant, similar to those found in flowering plants. Because of this, gnetophytes were once thought to be the closest gymnosperm relatives to flowering plants, but more recent molecular studies have brought this hypothesis into question, with many recent phylogenies finding them to be nested within the conifers.
Amborella is a monotypic genus of understory shrubs or small trees endemic to the main island, Grande Terre, of New Caledonia in the southwest Pacific Ocean. The genus is the only member of the family Amborellaceae and the order Amborellales and contains a single species, Amborella trichopoda. Amborella is of great interest to plant systematists because molecular phylogenetic analyses consistently place it as the sister group to all other flowering plants, meaning it was the earliest group to evolve separately from all other flowering plants.
A tracheid is a long and tapered lignified cell in the xylem of vascular plants. It is a type of conductive cell called a tracheary element. Angiosperms use another type of conductive cell, called vessel elements, to transport water through the xylem. The main functions of tracheid cells are to transport water and inorganic salts, and to provide structural support for trees. There are often pits on the cell walls of tracheids, which allows for water flow between cells. Tracheids are dead at functional maturity and do not have a protoplast. The wood (softwood) of gymnosperms such as pines and other conifers is mainly composed of tracheids. Tracheids are also the main conductive cells in the primary xylem of ferns.
Winteraceae is a primitive family of tropical trees and shrubs including 93 species in five genera. It is of particular interest because it is such a primitive angiosperm family, distantly related to Magnoliaceae, though it has a much more southern distribution. Plants in this family grow mostly in the southern hemisphere, and have been found in tropical to temperate climate regions of Malesia, Oceania, eastern Australia, New Zealand, Madagascar and the Neotropics, with most of the genera concentrated in Australasia and Malesia. The five genera, Takhtajania, Tasmannia, Drimys, Pseudowintera, and Zygogynum s.l. all have distinct geographic extant populations. Takhtajania includes a single species, T. perrieri, endemic only to Madagascar, Tasmannia has the largest distribution of genera in Winteraceae with species across the Philippines, Borneo, New Guinea, Eastern Australia, and Tasmannia, Drimys is found in the Neotropical realm, from southern Mexico to the subarctic forests of southern South America, Pseudowintera is found only in New Zealand, and Zygogynum has species in New Guinea and New Caledonia.
Menyanthaceae is a family of aquatic and wetland plants in the order Asterales. There are approximately 60-70 species in six genera distributed worldwide. The simple or compound leaves arise alternately from a creeping rhizome. In the submersed aquatic genus Nymphoides, leaves are floating and support a lax, umbellate or racemose inflorescence. In other genera the inflorescence is erect and consists of one to many flowers. The sympetalous, insect-pollinated flowers are five-parted and either yellow or white. The petals are ciliate or adorned with lateral wings. Fruit type is a capsule.
A vessel element or vessel member is one of the cell types found in xylem, the water conducting tissue of plants. Vessel elements are found in most angiosperms but absent from most gymnosperms such as conifers. Vessel elements are the main feature distinguishing the "hardwood" of angiosperms from the "softwood" of conifers.
Phelline is a genus of shrubs and the sole member of the family Phellinaceae, a family of flowering plants endemic to New Caledonia. It is placed in the order Asterales and is related to two other small plant families: Alseuosmiaceae and Argophyllaceae. It contains ten species.
Trochodendraceae is the only family of flowering plants in the order Trochodendrales. It comprises two extant genera, each with a single species along with up to five additional extinct genera and a number of extinct species. The living species are native to south east Asia. The two living species both have secondary xylem without vessel elements, which is quite rare in angiosperms. As the vessel-free wood suggests primitiveness, these two species have attracted much taxonomic attention.
Chloranthaceae is a family of flowering plants (angiosperms), the only family in the order Chloranthales. It is not closely related to any other family of flowering plants, and is among the early-diverging lineages in the angiosperms. They are woody or weakly woody plants occurring in Southeast Asia, the Pacific, Madagascar, Central and South America, and the West Indies. The family consists of four extant genera, totalling about 77 known species according to Christenhusz and Byng in 2016. Some species are used in traditional medicine. The type genus is Chloranthus. The fossil record of the family, mostly represented by pollen such as Clavatipollenites, extends back to the dawn of the history of flowering plants in the Early Cretaceous, and has been found on all continents.
Asteliaceae is a family of flowering plants, placed in the order Asparagales of the monocots.
Lanaria is a monotypic genus of flowering plants containing a single species, Lanaria lanata, endemic to the southern coast of South Africa where it is associated with the fynbos belt. Lanaria lanata is commonly known as Cape edelweiss or lambtails. The genus is placed in the monotypic family Lanariaceae, a family only recently recognized by taxonomists. The APG IV system of 2016 does recognize this family.
Trochodendron aralioides, sometimes colloquially called wheel tree, is a flowering plant and the sole living species in the genus Trochodendron, which also includes several extinct species. It was also often considered the sole species in the family Trochodendraceae, though botanists now include the distinct genus Tetracentron in the same family. T. aralioides is native to Japan, southern Korea and Taiwan. Growing in lower temperate montane mixed forests in Japan, and broad-leaved evergreen forest in the central mountain ranges and Northern parts of Taiwan.
Daphniphyllum is the sole genus in the flowering plant family Daphniphyllaceae and was described as a genus in 1826. The genus includes evergreen shrubs and trees mainly native to east and southeast Asia, but also found in the Indian Subcontinent and New Guinea.
Goodeniaceae is a family of flowering plants in the order Asterales. It contains about 404 species in twelve genera. The family is distributed mostly in Australia, except for the genus Scaevola, which is pantropical. Its species are found across most of Australia, being especially common in arid and semi-arid climates.
Lepidodendrales or arborescent lycophytes are an extinct order of primitive, vascular, heterosporous, arborescent (tree-like) plants belonging to Lycopodiopsida. Members of Lepidodendrales are the best understood of the fossil lycopsids due to the vast diversity of Lepidodendrales specimens and the diversity in which they were preserved; the extensive distribution of Lepidodendrales specimens as well as their well-preservedness lends paleobotanists exceptionally detailed knowledge of the coal-swamp giants’ reproductive biology, vegetative development, and role in their paleoecosystem. The defining characteristics of the Lepidodendrales are their secondary xylem, extensive periderm development, three-zoned cortex, rootlike appendages known as stigmarian rootlets arranged in a spiralling pattern, and megasporangium each containing a single functional megaspore that germinates inside the sporangium. Many of these different plant organs have been assigned both generic and specific names as relatively few have been found organically attached to each other. Some specimens have been discovered which indicate heights of 40 and even 50 meters and diameters of over 2 meters at the base. The massive trunks of some species branched profusely, producing large crowns of leafy twigs; though some leaves were up to 1 meter long, most were much shorter, and when leaves dropped from branches their conspicuous leaf bases remained on the surface of branches. Strobili could be found at the tips of distal branches or in an area at the top of the main trunk. The underground organs of Lepidodendrales typically consisted of dichotomizing axes bearing helically arranged, lateral appendages serving an equivalent function to roots. Sometimes called "giant club mosses", they are believed to be more closely related to extant quillworts based on xylem, although fossil specimens of extinct Selaginellales from the Late Carboniferous also had secondary xylem.
Rotafolia is a genus of the extinct Sphenophyllales horsetails. The species Rotafolia songziensis was first described as Bowmanites songziensis in 1984, based on a fossilized strobilus, and transferred to the new genus Rotafolia in 2005.
