| Arjona | |
|---|---|
 | |
| Arjona patagonica | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Order: | Santalales |
| Family: | Schoepfiaceae |
| Genus: | Arjona Cav. [1] |
Arjona is a genus of flowering plants in the family Schoepfiaceae. [2] They are hemiparasites. [3]
As of December 2017 [update] , the following six species were recognized by the Plants of the World Online database: [4]
The Flora del Conosur does not accept A. schumanniana, which was synonymised with A. megapotamica by the Brazilian botanist João Rodrigues de Mattos in the Santalales volume of the Flora Ilustrada Catarinense of 1967. [5]
A 2019 study of the genetics of the mainly Andean species of this genus was not able to include Arjona megapotamica (of which Arjona schumanniana was treated as a synonym). The results suggested that there are only one to three highly morphologically variable species, similar to the related genus Quinchamalium or the mistletoe species Tristerix corymbosus . Arjona megapotamica may be a separate valid species. The samples sequenced could be broadly placed in two regional groups, but these appear to be very closely related. Because the morphology of individual plants is so variable, it is difficult to identify a particular sample to a species, and the phenotypes exhibited by the individuals do not appear to be correlated to genetic clades. [3] Nonetheless, a 1977 Ph.D. dissertation by Feur found diverse heteropolar pollen distinguishing species of Arjona. [6]
The species all have tubers. These tubers are rhizomes, underground stems, not roots. The roots do not sprout exactly from the tuber itself, but from its uppermost part (the tubers may grow upside down, with the stems arising from the bottom), where it becomes the vegetative stems. In some species, such as Arjona pusilla, the rhizomes can branch and grow laterally, forming an underground mat of sorts. Others have napiform tubers, and others more long and thin tubers. The actual roots are small and thin, and have organs called 'haustoria', which are used to parasitise upon surrounding plants. All species grow a tuft of unbranched or weakly branched stems, topped eventually by an inflorescence. [7]
The five or six species are found in southern South America, stretching from Tierra del Fuego in the south, north to Peru in the west, and southeastern Brazil in the east. [4] [8] Assuming A. schumanniana is not a valid species, Argentina has four species, Chile has three, Bolivia, Peru and Uruguay have a single species. [4] Brazil has a single endemic species. [3] [8]
All species are found in open, not forested situations. Arjona patagonica and A. tuberosa appear to have broad habitat adaptability, but may prefer sandy soils. A. tuberosa var. tandilensis only appears to grow upon solitary hills of some 400-500m in height which rise above the pampas in some areas in central Argentina (La Pampa Province and Buenos Aires), or on higher, again solitary, mountains of 1500m in Córdoba Province or Uruguay. A. megapotamica is found on cold mountaintops in southeastern Brazil. All other species are found in dry climates, except A. pusilla, which is the only species to grow in wet environments. [3]
Arjona species are root hemiparasites, able to derive a portion of their nutrition by having specialised organs on their roots which can attach to the roots of the host plants. The host plants involved generally appear to be species of grass. [7]
A. tuberosa has relatively watery nectar, the sugars in it having a relatively high proportion of glucose and fructose, and a low percentage of sucrose. Its flowers are mostly visited by butterflies. [9]
The small tubers of Arjona patagonica were collected by the Ona people as a food in Patagonia. [10] The tubers of Arjona tuberosa , called macachín, yaukuna or chaquil in various languages, are collected as a food by the inhabitants of the Monte Desert; these are largely non-indigenous Mapuche people, who began to colonise the area in the 17th century. The collectors are generally men (women stay at home now due to the schooling requirements of children) who raise cattle and travel through the desert in search of pasture during the summer season (transhumanism). [11]
The Santalales are an order of flowering plants with a cosmopolitan distribution, but heavily concentrated in tropical and subtropical regions. It derives its name from its type genus Santalum (sandalwood). Mistletoe is the common name for a number of parasitic plants within the order.
Loranthaceae, commonly known as the showy mistletoes, is a family of flowering plants. It consists of about 75 genera and 1,000 species of woody plants, many of them hemiparasites. The three terrestrial species are Nuytsia floribunda, Atkinsonia ligustrina, and Gaiadendron punctatum Loranthaceae are primarily xylem parasites, but their haustoria may sometimes tap the phloem, while Tristerix aphyllus is almost holoparasitic. For a more complete description of the Australian Loranthaceae, see Flora of Australia online., for the Malesian Loranthaceae see Flora of Malesia.
Ceratophyllum is a cosmopolitan genus of flowering plants including four accepted living species in 2016, commonly found in ponds, marshes, and quiet streams in tropical and in temperate regions. It is the only extant genus in the family Ceratophyllaceae, itself the only extant family in the order Ceratophyllales. They are usually called coontails or hornworts, although hornwort is also used for unrelated plants of the division Anthocerotophyta.
Alstroemeriaceae is a family of flowering plants, with 254 known species in four genera, almost entirely native to the Americas, from Central America to southern South America. One species of Luzuriaga occurs in New Zealand, and the genus Drymophila is endemic to south-eastern Australia.
Schinus is a genus of flowering trees and tall shrubs in the sumac family, Anacardiaceae. Members of the genus are commonly known as pepper trees. The Peruvian pepper tree is the source of the spice known as pink peppercorn.
Grindelia (gumweed) is a genus of plants native to the Americas belonging to the family Asteraceae. The genus was named for Latvian botanist David Hieronymus Grindel, 1776–1836.
Ruppia, also known as the widgeonweeds, ditch grasses or widgeon grass, is the only extant genus in the family Ruppiaceae, with eight known species. These are aquatic plants widespread over much of the world. The genus name honours Heinrich Bernhard Rupp, a German botanist (1688-1719). They are widespread outside of frigid zones and the tropics.
Blandfordia, commonly known as Christmas bells, is a genus of four species of flowering plants native to eastern Australia. Christmas bells are tufted, perennial herbs with narrow, linear leaves and up to twenty large, drooping, cylindrical or bell-shaped flowers.
Olacaceae is a family of flowering plants in the order Santalales. They are woody plants, native throughout the tropical regions of the world. As of July 2021, the circumscription of the family varies; some sources maintain a broad family, others split it into seven segregate families.
Schoepfiaceae is a family of flowering plants recognized in the APG III system of 2009. The family was previously only recognized by few taxonomists; the plants in question usually being assigned to family Olacaceae and Santalaceae.
Danthonia is a genus of Eurasian, North African, and American plants in the grass family. Members of this genus are sometimes referred to as oatgrass, but that common name is not restricted to this genus. Other common names include heathgrass and wallaby grass. Australian species have since been reclassified into the genus Rytidosperma.
Polypogon is a nearly cosmopolitan genus of plants in the grass family, commonly known beard grass or rabbitsfoot grass.
Eclipta is a genus of flowering plants in the family Asteraceae.
Oziroe is a genus of bulbous South American plants in the squill subfamily within the asparagus family. Within the Scilloideae, it is the sole member of the tribe Oziroëeae and the only genus in the subfamily to be found in the New World.
Genlisea tuberosa is a carnivorous species in the genus Genlisea that is endemic to Brazil and found only in campos rupestres vegetation. Lacking any roots, it has unpigmented bundles of "rootlike" subterranean organs, technically leaves, which attract, trap, and digest protozoans. This species is unique in the genus in its formation of tubers. As of 2014, Genlisea tuberosa has the smallest known genome of any flowering plant, at 61 Mbp, or 61,000,000 base pairs.
Arjona patagonica is a species of flowering plant in the family Schoepfiaceae native to southern South America.
Quinchamalium is a genus of flowering plant in the family Schoepfiaceae, with a single species Quinchamalium chilense, native to Chile, Argentina, Peru and Bolivia. Depending on the latitude, it can be found from sea level to 3,800 m in altitude.
Boopis is a genus of flowering plants in the family Calyceraceae, native to Chile, Argentina and Brazil. The taxon is believed to be highly polyphyletic.
Arjona megapotamica is a rare species of flowering plant in the family Schoepfiaceae, native to a small area of southeastern Brazil, where it grows in cool mountain grasslands. Like other Arjona species, it is thought to be a root hemiparasite. It is a small perennial plant growing as a bunch of short twigs from a woody central knob. As of December 2021, Arjona schumanniana was regarded by some sources as a synonym, by others as an independent species.
Alstroemerieae is the name of a tribe of monocotyledonous, herbaceous, perennial plants belonging to the Alstroemeriaceae family. They are native to Central and South America. They have very vivid flowers, relatively large and of various colors. Because of the beauty of their flowers, they are often used as ornamental plants and, especially, as cut flowers.
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