Hydnoroideae | |
---|---|
Prosopanche americana | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Magnoliids |
Order: | Piperales |
Family: | Aristolochiaceae |
Subfamily: | Hydnoroideae Walpers |
Genera | |
Hydnoroideae distribution map |
Hydnoroideae is a subfamily of parasitic flowering plants in the order Piperales. Traditionally, and as recently as the APG III system it given family rank under the name Hydnoraceae. [1] It is now submerged in the Aristolochiaceae. [2] [3] It contains two genera, Hydnora and Prosopanche : [2]
Members of this subfamily have been described as the strangest plants in the world. [4]
The most striking aspect of the Hydnoroideae is probably the complete absence of leaves (not even in modified forms such as scales). [2] Some species are mildly thermogenic (capable of producing heat), presumably as a means of dispersing their scent. [5]
The plants are pollinated by insects such as dermestid beetles or carrion flies, attracted by the fetid odor of the flowers. [2] In Hydnora africana there are bait bodies with a strong smell, whereas in Hydnora johannis the scent comes from a region at the tip of the perianth called a cucullus. [2] The flowers may be above ground or underground. [2] The fruits have edible, fragrant pulp, which attracts animals such as porcupines, monkeys, jackals, rhinoceros, and armadillos, as well as humans. The host plants, in the case of Hydnora, generally are in the family Euphorbiaceae and the genus Acacia . [2] Hosts for Prosopanche include various species of Prosopis and other legumes.[ citation needed ]
The complete plastid genome sequence of one species of Hydnoroideae, Hydnora visseri , has been determined. As compared to the chloroplast genome of its closest photosynthetic relatives, the plastome of Hydnora visseri shows extreme reduction in both size (27,233 bp) and gene content (24 genes appear to be functional). [7] The plastome of Hydnora visseri is therefore one of the smallest among flowering plants. [8]
Like many parasitic plants, the affinities with non-parasitic plants are not obvious, and 19th and 20th century botanists proposed a variety of placements for the taxon. Molecular data places them in the Piperales, and nested within the Aristolochiaceae and allied with the Piperaceae or Saururaceae. [3] [2] [9] [10]
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae, commonly called angiosperms. They include all forbs, grasses and grass-like plants, a vast majority of broad-leaved trees, shrubs and vines, and most aquatic plants. The term "angiosperm" is derived from the Greek words ἀγγεῖον / angeion and σπέρμα / sperma ('seed'), meaning that the seeds are enclosed within a fruit. They are by far the most diverse group of land plants with 64 orders, 416 families, approximately 13,000 known genera and 300,000 known species. Angiosperms were formerly called Magnoliophyta.
The Magnoliales are an order of flowering plants.
The Nymphaeales are an order of flowering plants, consisting of three families of aquatic plants, the Hydatellaceae, the Cabombaceae, and the Nymphaeaceae. It is one of the three orders of basal angiosperms, an early-diverging grade of flowering plants. At least 10 morphological characters unite the Nymphaeales. One of the traits is the absence of a vascular cambium, which is required to produce both xylem (wood) and phloem, which therefore are missing. Molecular synapomorphies are also known.
Piperales is an order of flowering plants. It necessarily includes the family Piperaceae but other taxa have been included or disincluded variously over time. Well-known plants which may be included in this order include black pepper, kava, the many Peperomias, pepper elder, lizard's tail, birthwort, and wild ginger.
Aristolochiales is an order of flowering plants. It is not recognised in the APG or APG II systems, in which it is considered a synonym of Piperales. It also is not recognized in the Thorne system.
The Aristolochiaceae are a family, the birthwort family, of flowering plants with seven genera and about 400 known species belonging to the order Piperales. The type genus is Aristolochia L.
The Buxales are a small order of eudicot flowering plants, recognized by the APG IV system of 2016. The order includes the family Buxaceae; the families Didymelaceae and Haptanthaceae may also be recognized or may be included in the Buxaceae. Many members of the order are evergreen shrubs or trees, although some are herbaceous perennials. They have separate "male" (staminate) and "female" (carpellate) flowers, mostly on the same plant. Some species are of economic importance either for the wood they produce or as ornamental plants.
The Piperaceae, also known as the pepper family, are a large family of flowering plants. The group contains roughly 3,600 currently accepted species in 5 genera. The vast majority of species can be found within the two main genera: Piper and Peperomia.
Orobanchaceae, the broomrapes, is a family of mostly parasitic plants of the order Lamiales, with about 90 genera and more than 2000 species. Many of these genera were formerly included in the family Scrophulariaceae sensu lato. With its new circumscription, Orobanchaceae forms a distinct, monophyletic family. From a phylogenetic perspective, it is defined as the largest crown clade containing Orobanche major and relatives, but neither Paulownia tomentosa nor Phryma leptostachya nor Mazus japonicus.
Saururaceae is a plant family comprising four genera and seven species of herbaceous flowering plants native to eastern and southern Asia and North America. The family has been recognised by most taxonomists, and is sometimes known as the "lizard's-tail family". The APG IV system assigned it to the order Piperales in the clade magnoliids.
In the APG IV system (2016) for the classification of flowering plants, the name asterids denotes a clade. Asterids is the largest group of flowering plants, with more than 80,000 species, about a third of the total flowering plant species. Well-known plants in this clade include the common daisy, forget-me-nots, nightshades, the common sunflower, petunias, yacon, morning glory, lettuce, sweet potato, coffee, lavender, lilac, olive, jasmine, honeysuckle, ash tree, teak, snapdragon, sesame, psyllium, garden sage, table herbs such as mint, basil, and rosemary, and rainforest trees such as Brazil nut.
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.
Lactoris fernandeziana is a flowering shrub endemic to the cloud forest of Masatierra — Robinson Crusoe Island, of the Juan Fernández Islands archipelago of Chile. It is the only extant species in the genus Lactoris.
The Rafflesiaceae are a family of rare parasitic plants comprising 36 species in 3 genera found in the tropical forests of east and southeast Asia, including Rafflesia arnoldii, which has the largest flowers of all plants. The plants are endoparasites of vines in the genus Tetrastigma (Vitaceae) and lack stems, leaves, roots, and any photosynthetic tissue. They rely entirely on their host plants for both water and nutrients, and only then emerge as flowers from the roots or lower stems of the host plants.
Hydnora africana is an achlorophyllous plant in the subfamily Hydnoroideae, native to southern Africa that is parasitic on the roots of members of the family Euphorbiaceae. It is also called jakkalskos or jackal food. The specific epithet africana means to be from Africa. Molecular data has suggested that Hydnoroideae is a "basal angiosperm" solidifying its place among the more primitive flowering plants. Hydnoraceae are the only angiosperms known to have no leaves or scales and are considered obligate parasites, completely dependent on their hosts to survive. The plant grows underground, except for a fleshy flower that emerges above ground and emits an odour of faeces to attract its natural pollinators, dung beetles and carrion beetles. The vegetative body of the plants has been reduced to only consisting of roots and flowers. The flowers act as temporary traps, retaining the beetles that enter long enough for them to pick up pollen.
The basal angiosperms are the flowering plants which diverged from the lineage leading to most flowering plants. In particular, the most basal angiosperms were called the ANITA grade, which is made up of Amborella, Nymphaeales and Austrobaileyales.
Hydnora triceps is a holoparasitic flowering plant native to Africa that grows on the roots of Euphorbia dregeana. Completely lacking in chlorophyll, it depends on its host for water and nutrients. The plant structure is composed of only specialized stems, buds, and haustoria, lacking any leaf-like structures entirely. It spends its life underground and only emerges to flower.
Hydnora is a group of parasitic plants described as a genus in 1775. It is native to Africa, Madagascar, and the Arabian Peninsula. Hydnora pollinates through brood-site mimicry. This is a method of pollination in which the plant emits a smell that is attractive to insects, so that the plant can trap the insect and allow it to take pollen so that it can pollinate other Hydnora.
Hydnora visseri, the Visser's hydnora, is a subterranean holoparasitic plant, lacking leaves and roots, and is described from southwestern Namibia and northwestern South Africa and has the longest tepal lobes of all Hydnora species. The genus Hydnora is composed entirely of holoparasitic plants that attach to the root of their hosts and are restricted to Africa and southwestern Asia.
The anthophytes are a grouping of plant taxa bearing flower-like reproductive structures. They were formerly thought to be a clade comprising plants bearing flower-like structures. The group contained the angiosperms - the extant flowering plants, such as roses and grasses - as well as the Gnetales and the extinct Bennettitales.