''Arcytophyllum'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. They include all forbs (flowering plants without a woody stem), grasses and grass-like plants, a vast majority of ...

s in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Rubiaceae The Rubiaceae are a family of flowering plants, commonly known as the coffee, madder, or bedstraw family. It consists of terrestrial trees, shrubs, lianas, or herbs that are recognizable by simple, opposite leaves with interpetiolar stipules ...

. The genus contains 18 species, distributed from

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe, New Mexico, Santa Fe , LargestCity = Albuquerque, New Mexico, Albuquerque , LargestMetro = Albuquerque metropolitan area, Tiguex , Offi ...

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

Description

Members of this genus are shrubs or dwarf shrubs that occupy mountainous habitats. Their leaves are oppositely arranged, small, sessile or sub-sessile, and possess inconspicuous secondary venation. Flowers are tetra- or pentamerous, with the stamens adnate to the white or pink funnelform or salverform corolla. The fruit is a capsule with septicidal dehiscence.

Species

* '' Arcytophyllum aristatum'' Standl. - Colombia, Ecuador * '' Arcytophyllum cachirense'' ( H.Karst.) K.Schum. - Colombia * '' Arcytophyllum capitatum'' (

Benth. George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studie ...

) K.Schum. - Colombia, Ecuador * '' Arcytophyllum ciliolatum'' Standl. - Ecuador, Perú * '' Arcytophyllum ericoides'' ( Willd. ex

Roem. Johann Jacob Roemer (8 January 1763, Zurich – 15 January 1819) was a physician and professor of botany in Zurich, Switzerland. He was also an entomologist. With Austrian botanist Joseph August Schultes, he published the 16th edition of Carl ...

Schult. Josef (Joseph) August Schultes (15 April 1773 in Vienna – 21 April 1831 in Landshut) was an Austrian botanist and professor from Vienna. Together with Johann Jacob Roemer (1763–1819), he published the 16th edition of Linnaeus' ''Systema ...

) Standl. - Ecuador, Perú * '' Arcytophyllum fasciculatum'' (

A.Gray Asa Gray (November 18, 1810 – January 30, 1888) is considered the most important American botanist of the 19th century. His '' Darwiniana'' was considered an important explanation of how religion and science were not necessarily mutually exc ...

) Terrell & H.Rob. - New Mexico, Texas,

Coahuila Coahuila (), formally Coahuila de Zaragoza (), officially the Free and Sovereign State of Coahuila de Zaragoza ( es, Estado Libre y Soberano de Coahuila de Zaragoza), is one of the 32 states of Mexico. Coahuila borders the Mexican states of N ...

* '' Arcytophyllum filiforme'' ( Ruiz & Pav.) Standl. - Bolivia, Perú, Ecuador, Colombia * '' Arcytophyllum lavarum'' K.Schum. - Costa Rica, Panamá * '' Arcytophyllum macbridei'' Standl. - Amazonas (of Perú) * '' Arcytophyllum muticum'' (

Wedd. Hugh Algernon Weddell (22 June 1819 – 22 July 1877) was a physician and botanist, specialising in South American flora. Weddell was born at Birches House, Painswick near Gloucester, England but was raised in France and educated ...

) Standl. - Costa Rica, Panamá, Colombia, Ecuador, Venezuela * '' Arcytophyllum nitidum'' (

Kunth Carl Sigismund Kunth (18 June 1788 – 22 March 1850), also Karl Sigismund Kunth or anglicized as Charles Sigismund Kunth, was a German botanist. He is known for being one of the first to study and categorise plants from the American continent ...

) Schltdl. - Colombia, Venezuela * '' Arcytophyllum peruvianum'' (Wernham) J.H.Kirkbr. - Perú * '' Arcytophyllum rivetii'' Danguy & Cherm. - Ecuador, Perú * '' Arcytophyllum serpyllaceum'' ( Schltdl.) Terrell - Guatemala, Chiapas, Veracruz, Oaxaca * '' Arcytophyllum setosum'' ( Ruiz & Pav.) Schltdl. - Bolivia, Perú, Ecuador, Colombia * '' Arcytophyllum thymifolium'' ( Ruiz & Pav.) Standl. - Colombia, Ecuador, Perú * '' Arcytophyllum venezuelanum''

Steyerm. Julian Alfred Steyermark (January 27, 1909 – October 15, 1988) was a Venezuelan American botanist. His focus was on New World vegetation, and he specialized in the family Rubiaceae. Life and work Julian Alfred Steyermark was born in St. Louis, ...

- Venezuela * '' Arcytophyllum vernicosum'' Standl. - Ecuador, Peru

Phylogeny and biogeography

''Arcytophyllum'' is a

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic ...

genus when ''A. serpyllaceum'' is excluded, as this species has been shown to be more closely related to '' Bouvardia'' but has not been formally transferred to another genus. The remaining species are most closely related to the North American and Caribbean genus '' Houstonia'' (including ''Stenaria'') and one species of the polyphyletic genus ''Oldenlandia'' (''Oldenlandia microtheca'') distributed in Mexico and Central America, indicating that ''Arcytophyllum'' may be one of the few cases in the family

of a southward migration to reach the Andes. The center of diversity is in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

; namely in

Ecuador Ecuador ( ; ; Quechuan languages, Quechua: ''Ikwayur''; Shuar language, Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechuan ...

, where 10 species are documented.

Floral morphology and evolution

Flowers of ''Arcytophyllum'' are distylous, meaning that two morphs exist differing in the vertical orientation of anthers and stigmas. Pin morphs have stigmas positioned above the anthers, while thrum morphs have stigmas positioned below the anthers. A study of 11 species showed significantly higher seed production in thrum than pin morphs of ''A. aristatum'', ''A. lavarum'', and ''A. vernicosum'', and a similar tendency in all other sampled species. In contrast, pin morphs of ''A. lavarum'' cross pollinate more efficiently than thrum morphs, thus transmitting more of their genes to the next generation via pollen than seed. As better exporters of pollen to flowers of the opposite morph, long-styled ''A. lavarum'' give rise to disassortative pollen flow and a division in reproductive functions between the morphs. If pollinators promote the condition of distyly and asymmetric pollen flow over evolutionary time, it is plausible that gender specialization will evolve into

dioecy Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

References

External links

Encyclopedia of Life

Global Biodiversity Information Facility

The Plant List

''Arcytophyllum'' in the World Checklist of Rubiaceae
{{Taxonbar, from=Q4787754 Rubiaceae genera Spermacoceae Flora of Central America