Exostema

Exostema is a genus of flowering plants in the family Rubiaceae. It consists of trees and shrubs, endemic to the neotropics, with most of the species occurring in the West Indies.^[1][2]

Exostema
Illustration of Exostemma caribaeum
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Gentianales
Family:	Rubiaceae
Subfamily:	Cinchonoideae
Tribe:	Chiococceae
Genus:	Exostema (Pers.) Rich. ex Humb. & Bonpl.
Type species
Exostema caribaeum (Jacq.) Schult.
Synonyms
Solenandra Hook.f. Steudelago Kuntze

Description

Exostema is a genus of neotropical trees and shrubs. The flowers have a slender corolla tube with recurved corolla lobes. The stamens are inserted near the base of the corolla tube and exserted well beyond its mouth. The anthers are long and basifixed.^[3]

Systematics

The type species for the genus is Exostema caribaeum.^[4] It is a tree of Central America and the Caribbean. Its lumber is of limited use.^[1]

Exostema was first named by Christiaan Hendrik Persoon as a subgenus of Cinchona.^[5] It was first validly published as a genus by Aimé Bonpland in 1807.^[6][7] The generic name is derived from the Ancient Greek words, exo, meaning "outside", and stema, "stamen".^[8]

As circumscribed in 2010, Exostema was probably polyphyletic.^[9] Species have since been moved to other genera.

Species

As of March 2023^[update], Plants of the World Online accepted the following species:^[10]

• Exostema acuminatum Urb.
• Exostema bicolor Poepp.
• Exostema caribaeum (Jacq.) Schult.
• Exostema coriaceum (Poir.) Schult.
• Exostema glaberrimum Borhidi & M.Fernández
• Exostema lancifolium Borhidi & Acuña
• Exostema nitens Urb.
• Exostema purpureum Griseb.
• Exostema revolutum Borhidi & M.Fernández
• Exostema salicifolium Griseb.
• Exostema spinosum (Le Vavass.) Krug & Urb.

References

1. Mabberley DJ (2008). Mabberley's Plant Book (3 ed.). Cambridge University Press. ISBN 978-0-521-82071-4.
2. "Exostema in the World Checklist of Rubiaceae". Retrieved 20 June 2014.
3. McDowell T; Bremer B (1998). "Phylogeny, diversity, and distribution in Exostema (Rubiaceae): implications of morphological and molecular analyses". Plant Systematics and Evolution. 212 (3–4): 215–246. Bibcode:1998PSyEv.212..215M. doi:10.1007/bf01089740. S2CID 23714607.
4. "Exostema in the Index Nominum Genericorum". Retrieved 20 June 2014.
5. Christiaan Hendrik Persoon. 1805. Synopsis plantarum,seu Enchiridium botanicum, complectens enumerationem systematicam specierum hucusque cognitarum /curante. 1:196.
6. "Exostema in the International Plant Names Index". Retrieved 20 June 2014.
7. Alexander von Humboldt and Aimé Bonpland. 1807. Plantes équinoxiales recueillies au Mexique :dans l'île de Cuba, dans les provinces de Caracas, de Cumana et de Barcelone, aux Andes de la Nouvelle Grenade, de Quito et du Pérou, et sur les bords du rio-Negro de Orénoque et de la rivière des Amazones. 1:131. F. Schoell: Paris, France.
8. Quattrocchi U (2000). CRC World Dictionary of Plant Names. Vol. 1. Boca Raton, New York, Washington DC, London: CRC Press. ISBN 978-0-8493-2675-2.
9. Manns U, Bremer B (2010). "Towards a better understanding of intertribal relationships and stable tribal delimitations within Cinchonoideae s.s. (Rubiaceae)". Molecular Phylogenetics and Evolution. 56 (1): 21–39. doi:10.1016/j.ympev.2010.04.002. PMID 20382247.
10. "Exostema (Pers.) Bonpl". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2023-03-19.

External links

• Exostema At World Checklist of Selected Plant Families
• Exostema At Index Nominum Genericorum
• Exostema At Biodiversity Heritage Library
• Exostema At IPNI
• Exostema At GRIN taxonomy for plants
• Exostema At UniProt