This article needs additional citations for verification .(September 2014) |
Orobanchaceae | |
---|---|
![]() | |
Lesser broomrape ( Orobanche minor ) | |
Scientific classification ![]() | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Asterids |
Order: | Lamiales |
Family: | Orobanchaceae Vent. [1] |
Tribes [2] | |
Synonyms [3] | |
|
Orobanchaceae, the broomrapes, is a family of mostly parasitic plants of the order Lamiales, with about 90 genera and more than 2000 species. [4] Many of these genera (e.g., Pedicularis , Rhinanthus , Striga ) were formerly included in the family Scrophulariaceae sensu lato . [5] [6] [7] With its new circumscription, Orobanchaceae forms a distinct, monophyletic family. [7] 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 . [8] [9]
The Orobanchaceae are annual herbs or perennial herbs or shrubs, and most (all except Lindenbergia , Rehmannia and Triaenophora ) are parasitic on the roots of other plants—either holoparasitic or hemiparasitic (fully or partly parasitic). The holoparasitic species lack chlorophyll and therefore cannot perform photosynthesis.
Orobanchaceae is the largest of the 20–28 dicot families that express parasitism. [10] Apart from a few non-parasitic taxa, the family displays all types of plant parasitism: facultative parasite, obligate parasite, hemiparasites, and holoparasites.
Parasitic plants are attached to their host by means of haustoria, which transfer nutrients from the host to the parasite. Only the hemiparasitic species possess an additional extensive root system referred to as the lateral or side haustoria. In most holoparasitic species there is a swollen mass of short, bulky roots or one big swollen haustorial organ, which may be simple or composite, commonly called the terminal or primary haustorium. [11]
Plants are reduced to short vegetative stems, their alternate leaves are reduced to fleshy, tooth-like scales, and have multicellular hairs interspersed with glandular hairs. [12]
The hemiparasitic species (transferred from Scrophulariaceae) with green leaves are capable of photosynthesis, and may be either facultative or obligate parasites.
The hermaphroditic flowers are bilaterally symmetrical and grow either in racemes or spikes or singly at the apex of the slender stem. The tubular calyx is formed by 2–5 united sepals. There are five united, bilabiate petals forming the corolla and they may be yellowish, brownish, purplish, or white. The upper lip is two-lobed, the lower lip is three-lobed. There are two long and two short stamens on slender filaments, inserted below the middle, or at the base of the corolla tube, alternating with the lobes of the tube. A fifth stamen is either sterile or lacking completely. The anthers dehisce via longitudinal slits. The pistil is one-celled. The ovary is superior. The flowers are pollinated by insects or birds (e.g., hummingbirds, as in Castilleja ).
The fruit is a dehiscent, non-fleshy, 1-locular capsule with many very minute endospermic seeds. Fruits of Orobanchaceae are small and abundant and can produce between 10,000–1,000,000 seeds per plant. [13] These are dispersed by the wind over long distances, which increases their chances of finding a new host.
Development of the haustoria was a significant evolutionary event that allowed for the advancement of parasitic plants. The holoparasitic clade, Orobanche , delineates the first transition from hemiparasitism to holoparasitism within Orobanchaceae.
Despite the similar morphological traits found in both Scrophulariaceae and Orobanchaceae, the latter is now morphologically and molecularly considered monophyletic, though many of its genera were once considered a part of the family Scrophulariaceae.
Lindenbergia , once treated as a member of the Scrophulariaceae, is the one of the only autotrophic genera within Orobanchaceae. It is believed to be the sister group to the hemiparasitic genera within its family. [14]
The parasitism and its different modes have been suggested to have an impact on genome evolution, with increased DNA substitution rates in parasitic organisms compared to non-parasitic taxa. [15] For example, holoparasite taxa of Orobanchaceae exhibit faster molecular evolutionary rates than confamilial hemiparasites in three plastid genes. [16]
In a study comparing the rates of molecular evolution of parasitic versus non parasitic taxa for 12 pairs of angiosperm families — including Apodanthaceae, Cytinaceae, Rafflesiaceae, Cynomoriaceae, Krameriaceae, Mitrastemonaceae, Boraginaceae, Orobanchaceae, Convolvulaceae, Lauraceae, Hydnoraceae, and Santalaceae/Olacaceae —, parasitic taxa evolve on average faster than their close relatives for mitochondrial, plastid, and nuclear genome sequences. [17] Whereas Orobanchaceae fit to this trend for plastid DNA, they appear to evolve slower than their non parasitic counterpart in comparisons involving nuclear and mitochondrial DNA. [17]
99 genera are accepted. [3]
Orobanchaceae genera listed according to their life history trait.[ citation needed ]
The family Orobanchaceae has a cosmopolitan distribution, found mainly in temperate Eurasia, North America, South America, parts of Australia, New Zealand, and tropical Africa. The only exception to its distribution is Antarctica, though some genera may be found in subarctic regions. [18]
This family has tremendous economic importance because of the damage to crops caused by some species in the genera Orobanche and Striga . They often parasitize cereal crops like sugarcane, maize, millet, sorghum, and other major agricultural crops like cowpea, sunflower, hemp, tomatoes, and legumes. Because of the ubiquitous nature of these particular parasites in developing countries, it is estimated to affect the livelihood of over 100 million people, killing 20 to 100 percent of crops depending on infestation. [19]
Some genera, especially Cistanche and Conopholis , are threatened by human activity, including habitat destruction and over-harvesting of both the plants and their hosts.
Research for this plant family can often be difficult due to its permit requirements for collection, travel, and research.
The Scrophulariaceae are a family of flowering plants, commonly known as the figwort family. The plants are annual and perennial herbs, as well as shrubs. Flowers have bilateral (zygomorphic) or rarely radial (actinomorphic) symmetry. The Scrophulariaceae have a cosmopolitan distribution, with the majority found in temperate areas, including tropical mountains. The family name is based on the name of the included genus Scrophularia L.
Gesneriaceae, the gesneriad family, is a family of flowering plants consisting of about 152 genera and ca. 3,540 species in the tropics and subtropics of the Old World and the New World, with a very small number extending to temperate areas. Many species have colorful and showy flowers and are cultivated as ornamental plants.
Paulowniaceae are a family of flowering plants within the Lamiales. They are a monophyletic and monogeneric family of trees with currently 7 confirmed species. They were formerly placed within Scrophulariaceae sensu lato, or as a segregate of the Bignoniaceae.
Striga, commonly known as witchweed, is a genus of parasitic plants that occur naturally in parts of Africa, Asia, and Australia. It is currently classified in the family Orobanchaceae, although older classifications place it in the Scrophulariaceae. Some species are serious pathogens of cereal crops, with the greatest effects being in savanna agriculture in Africa. It also causes considerable crop losses in other regions, including other tropical and subtropical crops in its native range and in the Americas. The generic name derives from Latin strī̆ga, "witch".
Rehmannia is a genus of seven species of flowering plants in the order Lamiales and family Orobanchaceae, endemic to China. It has been placed as the only member of the monotypic tribe Rehmannieae, but molecular phylogenetic studies suggest that it forms a clade with Triaenophora. Contrary to the immense majority of the taxa of Orobanchaceae, Rehmannia is not parasitic.
Calceolaria, also called lady's purse, slipper flower and pocketbook flower, or slipperwort, is a genus of plants in the family Calceolariaceae, sometimes classified in Scrophulariaceae by some authors. This genus consists of about 388 species of shrubs, lianas and herbs, and the geographical range extends from Patagonia to central Mexico, with its distribution centre in Andean region. Calceolaria species have usually yellow or orange flowers, which can have red or purple spots. The Calceolaria Herbeohybrida group, also called C. herbeohybrida Voss, is a group of ornamental hybrids known only in cultivation, called florists' slipperwort.
Rhinanthus is a genus of annual hemiparasitic herbaceous plants in the family Orobanchaceae, formerly classified in the family Scrophulariaceae. Its species are commonly known as rattles. The genus consists of about 30 to 40 species found in Europe, northern Asia, and North America, with the greatest species diversity in Europe.
Torenia is a genus of plants now classified in the family Linderniaceae. Torenia has also been classified in the figwort family Scrophulariaceae. Often called wishbone flowers, bluewings; in Hawaii nanioola'a or ola'a beauty, some species are grown as garden plants. Many F1 and F2 Torenia hybrids have been hybridized in the last 30 years. Colors can range from white with yellow throats to violet, blue, cobalt, lavender and purple.
A parasitic plant is a plant that derives some or all of its nutritional requirements from another living plant. They make up about 1% of angiosperms and are found in almost every biome. All parasitic plants develop a specialized organ called the haustorium, which penetrates the host plant, connecting them to the host vasculature – either the xylem, phloem, or both. For example, plants like Striga or Rhinanthus connect only to the xylem, via xylem bridges (xylem-feeding). Alternately, plants like Cuscuta and some members of Orobanche connect to both the xylem and phloem of the host. This provides them with the ability to extract resources from the host. These resources can include water, nitrogen, carbon and/or sugars. Parasitic plants are classified depending on the location where the parasitic plant latches onto the host, the amount of nutrients it requires, and their photosynthetic capability. Some parasitic plants can locate their host plants by detecting volatile chemicals in the air or soil given off by host shoots or roots, respectively. About 4,500 species of parasitic plants in approximately 20 families of flowering plants are known.
Linderniaceae is a family of flowering plants in the order Lamiales, which consists of about 25 genera and 265 species occurring worldwide. Vandellia micrantha is eaten in Laos, but tastes bitter. Best known are the wishbone flowers Torenia fournieri and Torenia thouarsii, which are used as bedding plants, especially in the tropics. Micranthemum is sold as an aquarium plant when it is called 'baby tears'.
Bartsia is a genus of flowering plants in the family Orobanchaceae.
Lindenbergia is a genus of herbaceous plants in the order Lamiales and in the broomrape family Orobanchaceae. It is one of the few genera of the family which are not parasitic. It contains about 15 species found from northeast Africa across Asia to the Philippines, and is most abundant in India.
Orobanche minor, the hellroot, common broomrape, lesser broomrape, small broomrape or clover broomrape, is a holoparasitic flowering plant belonging to the family Orobanchaceae. It is one of about 150 non-photosynthetic plants in the genus Orobanche that parasitize autotrophic plants.
Rhamphicarpa fistulosa is a flowering plant species in the family Orobanchaceae - and the genus Rhamphicarpa. The plant is pale-green but can turn reddish towards maturity. It has needle-like leaves and white flowers with long corolla tubes. The flowers only open after sunset and are supposedly pollinated by night moths. The plant has a broad distribution in Africa and can also be found in New Guinea and northern Australia.
Boschniakia rossica, commonly known as the northern groundcone, is a holoparasitic plant that lives in the northern latitudes of the northern hemisphere. In the Pacific Northwest Temperate Rainforest, it does not grow south of Prince of Wales Island, beyond that boundary is the Vancouver groundcone habitat. It does not contain chlorophyll, so it must be parasitic to obtain nutrients. It specializes on Alnus species, but can parasitize off of other trees and shrubs such as on Betula (birch), Salix (willow), Vaccinium (blueberry), Picea (spruce), and Chamaedaphne. This organism is likely to be found at mid elevations alongside rivers and streams, where moisture is abundant. This species propagates itself through water flow. In some places bears are known to have eaten the starchy roots, or tubers, of this plant.
Orobanche hederae, the ivy broomrape, is, like other members of the genus Orobanche, a parasitic plant without chlorophyll, and thus totally dependent on its host, which is ivy. It grows to 60 cm (2 ft), with stems in shades of brown and purple, sometimes yellow. The flowers are 10–22 mm (0.4–0.9 in) long, cream in colour with reddish-purple veins.
Cycnium is a genus of flowering plants in the family Orobanchaceae. Its native range is tropical and southern Africa and Madagascar.
Hedbergia is a monotypic genus of flowering plants, initially classified in Scrophulariaceae, and now within the broomrape family Orobanchaceae. It contains a unique species, Hedbergia abyssinica. It is an afromontane genus, widespread in grasslands and scrubs of the mountains of tropical Africa, and known from Ethiopia, Zaire, Uganda, Kenya, Tanzania, Malawi, Nigeria, and Cameroons.
Triaenophora is a genus of flowering plants native to Temperate Asia. Its family placement is not fully settled, as of March 2022: it may be placed in Orobanchaceae or Plantaginaceae.
{{cite book}}
: |last1=
has generic name (help)CS1 maint: multiple names: authors list (link)