''Arcytophyllum'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Rubiaceae Rubiaceae () is a family (biology), 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 Petiole ( ...

. The genus contains 18 species, distributed from

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

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 Adnate may refer to: * Adnation, in botany, the fusion of two or more whorls of a flower * Adnate, in mycology, a classification of lamellae (gills) * Conjoined twins Conjoined twins, popularly referred to as Siamese twins, are twins joined '' ...

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. Carl Ludwig Willdenow (22 August 1765 – 10 July 1812) was a German botanist, pharmacist, and plant taxonomist. He is considered one of the founders of phytogeography, the study of the geographic distribution of plants. Willdenow was also ...

ex Roem. & Schult.) Standl. - Ecuador, Perú * '' Arcytophyllum fasciculatum'' ( A.Gray) Terrell & H.Rob. - New Mexico, Texas,

Coahuila Coahuila, formally Coahuila de Zaragoza, officially the Free and Sovereign State of Coahuila de Zaragoza, is one of the 31 states of Mexico. The largest city and State Capital is the city of Saltillo; the second largest is Torreón and the thi ...

* '' Arcytophyllum filiforme'' (

Ruiz The Spanish surname Ruiz is a patronymic from the personal name Ruy, a short form of Rodrigo, meaning "son of Roderick". Roderick's roots can be traced back to the Visigoths, the Germanic tribe which ruled in the Iberian Peninsula between the 5th an ...

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

Kunth Carl Sigismund Kunth (18 June 1788 – 22 March 1850) was a German botanist. He was also known as Karl Sigismund Kunth or anglicized as Charles Sigismund Kunth. He was one of the early systematic botanists who focused on studying the plants of th ...

)

Schltdl. Diederich Franz Leonhard von Schlechtendal (27 November 1794, Xanten – 12 October 1866, Halle an der Saale, Halle) was a German botanist. Life and work Von Schlechtendal was born in Xanten, Xanten am Rhein and when his father Diederich Fried ...

- Colombia, Venezuela * '' Arcytophyllum peruvianum'' (Wernham) J.H.Kirkbr. - Perú * '' Arcytophyllum rivetii'' Danguy & Cherm. - Ecuador, Perú * '' Arcytophyllum serpyllaceum'' (

) Terrell - Guatemala, Chiapas, Veracruz, Oaxaca * '' Arcytophyllum setosum'' (

& Pav.)

- Bolivia, Perú, Ecuador, Colombia * '' Arcytophyllum thymifolium'' (

& 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 biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

genus when ''A. serpyllaceum'' is excluded, as this species has been shown to be more closely related to ''

Bouvardia ''Bouvardia'' is a genus of flowering plants in the family Rubiaceae. It contains about 50 species of evergreen herbs and shrubs native to Mexico and Central America, with one species extending into the southwestern United States ('' B. ternifolia ...

'' 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 considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

; namely in

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

, 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 certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

References

External links

Encyclopedia of Life

Global Biodiversity Information Facility

The Plant List

''Arcytophyllum'' in the World Checklist of Rubiaceae
{{Authority control Rubiaceae genera Spermacoceae Flora of Central America