Question: Are Tweedia and Nematanthus both a genus of flowering plants?
Context: Nematanthus is a genus of flowering plants of the family Gesneriaceae.  All of its species are endemic to Brazil.  Compared to other gesneriads, "Nematanthus" has leaves that are small, succulent, and hard-surfaced.  The plant has a trailing, branching, and spreading habit; it is generally an epiphyte in nature and a hanging-basket plant in cultivation. Echinacea is a genus, or group of herbaceous flowering plants in the daisy family.  The "Echinacea" genus has nine species, which are commonly called purple coneflowers.  They are found only in eastern and central North America, where they are found growing in moist to dry prairies and open wooded areas.  They have large, showy heads of composite flowers, blooming from early to late summer.  The generic name is derived from the Greek word ἐχῖνος ("ekhinos"), meaning "hedgehog," due to the spiny central disk.  These flowering plants and their parts have different uses.  Some species are cultivated in gardens for their showy flowers.  "Echinacea purpurea" is used in folk medicine.  Two of the species, "E. tennesseensis" and "E. laevigata", are listed in the United States as endangered species. Psychotria is a genus of flowering plants in the Rubiaceae family.  It contains around 1,850 species and is therefore one of the largest genera of flowering plants.  The genus has a pantropical distribution and members of the genus are small understorey trees in tropical forests.  Some species are endangered or facing extinction due to deforestation, especially species of central Africa and the Pacific. Gnetophyta is a division of plants, grouped within the gymnosperms (which also includes conifers, cycads, and ginkgos), that consists of some 70 species across the three relict genera: "Gnetum" (family Gnetaceae), "Welwitschia" (family Welwitschiaceae), and "Ephedra" (family Ephedraceae).  Fossilized pollen attributed to a close relative of "Ephedra" has been dated as far back as the Early Cretaceous.  Though diverse and dominant in the Tertiary, only three families, each containing a single genus, are still alive today.  The primary difference between gnetophytes and other gymnosperms is the presence of vessel elements, a system of conduits 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 largely disproven this hypothesis. Columnea is a genus of ca. 200 species of epiphytic herbs and shrubs in the flowering plant family Gesneriaceae, native to tropical America and the Caribbean.  The tubular or oddly shaped flowers are usually large and brightly colored – usually red, yellow, or orange – sometimes resembling a fish in shape.  A common name is flying goldfish plants (see also the related "Nematanthus") due to the unusual flower shape. 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". Magnolia virginiana, most commonly known as sweetbay magnolia, or merely sweetbay (also laurel magnolia, swampbay, swamp magnolia, whitebay, or beaver tree), is a member of the magnolia family, Magnoliaceae.  It was the first magnolia to be scientifically described under modern rules of botanical nomenclature, and is the type species of the genus "Magnolia"; as "Magnolia" is also the type genus of all flowering plants (magnoliophytes), this species in a sense typifies all flowering plants. "Tweedia" is a genus of flowering plants in the Apocynaceae family, first described as a genus in 1835.  The genus is native to South America.  An ornamental plant, "Oxypetalum coeruleum", formerly included in this genus is commonly referred to as "tweedia". Austrobaileyales is an order of flowering plants, consisting of about 100 species of woody plants growing as trees, shrubs and lianas.  Perhaps the most familiar species is "Illicium verum", from which comes the spice star anise.  The order belongs to the group of basal angiosperms, the ANA grade, which diverged earlier from the remaining flowering plants, and, as such, it is the extant group after the Amborellales and Nymphaeales, that is sister to all remaining extant angiosperms outside of the ANA grade.  The order includes just three families of flowering plants, the Austrobaileyaceae, a monotypic family containing the sole genus, "Austrobaileya scandens", a woody liana, the Schisandraceae, a family of trees, shrubs, or lianas containing essential oils, and the Trimeniaceae, essential oil-bearing trees and lianas. Zeltnera is a genus of flowering plants in the gentian family.  It was erected in 2004 when the genus "Centaurium" (the centauries) was split.  Genetic analysis revealed that "Centaurium" was polyphyletic, made up of plants that could be grouped into four clades. Each became a genus.  "Centaurium" remained, but it is now limited to the Eurasian species.  The Mexican species now belong to genus "Gyrandra", and the Mediterranean and Australian plants are in genus "Schenkia".  The new name "Zeltnera" was given to this genus, which contains most of the North American centauries.  There are about 25 species.
Answer: yes