Hosta

Spermacoce or false buttonweed^[2] is a genus of flowering plants in the family Rubiaceae. It comprises about 275 species found throughout the tropics and subtropics.^[3] Its highest diversity is found in the Americas, followed by Africa, Australia and Asia.

Description

The species are herbs or small shrubs with small- to medium-sized, four-lobed flowers arranged in capitate inflorescences. Some have a brightly coloured calyx and are eye-catching, particularly the Australian species. The corolla is variable in colour, often white, but also all shades of blue, pink and maroon. The fruit is usually a two-seeded capsule, sometimes a schizocarp or nut.^[4]

Selected species

Spermacoce is a highly diverse genus with about 275 species in many tropical and subtropical places around the globe.^[3] North American species include:^[5]^[6]

Spermacoce alata Aubl. - West Indies, most of Latin America; naturalized in Africa, India, China, Southeast Asia, Australia, Melanesia
Spermacoce assurgens Ruiz & Pav. - synonym of Spermacoce remota^[3]
Spermacoce brachysepala (Urb.) Alain in H.A.Liogier & L.F.Martorell - West Indian false buttonweed - Puerto Rico, Haiti, Dominican Republic
Spermacoce capitata Ruiz & Pav. - baldhead false buttonweed - Central and South America from Belize to Argentina
Spermacoce confusa Rendle - river false buttonweed - Florida, West Indies, Latin America from Mexico to Argentina
Spermacoce densiflora (DC.) Alain - bouquet false buttonweed - Florida, West Indies, Latin America from Mexico to Argentina
Spermacoce ernestii Fosberg & Powell - synonym of Spermacoce ovalifolia^[3]
Spermacoce eryngioides (Cham. & Schltdl.) Kuntze - whorled-leaf false buttonweed - West Indies including Puerto Rico; southeastern South America from Bolivia and Brazil to Argentina
Spermacoce exilis (L.O. Williams) C. Adams - Pacific false buttonweed - Latin America from Mexico to Argentina, plus West Indies; naturalized in Africa, China, India, southeast Asia and some tropical oceanic islands
Spermacoce floridana Urb. - synonym of Spermacoce keyensis ^[3]
Spermacoce glabra Michx. - smooth false buttonweed - southern and eastern United States (mostly in the Lower Mississippi Valley); also South America
Spermacoce keyensis Urb. - Florida false buttonweed - southern Florida, Bahamas, southern tip of Texas (Cameron County)
Spermacoce latifolia Aubl. - synonym of Spermacoce alata^[3]
Spermacoce neoterminalis Govaerts - Everglades false buttonweed- southern Florida
Spermacoce ovalifolia (M. Martens & Galeotti) Hemsl. - broadleaf false buttonweed - West Indies including Puerto Rico, Latin America from Mexico to Paraguay
Spermacoce ocymoides Burm.f.
Spermacoce prostrata Aubl. - prostrate false buttonweed - Florida, Mississippi, Alabama, West Indies including Puerto Rico; most of Latin America; naturalized in China, Vietnam, Sri Lanka and Java
Spermacoce remota - Lam. - woodland false buttonweed - Florida, Georgia, Texas, Alabama, West Indies, much of Latin America; naturalized in Southeast Asia, China, India, New Guinea, Mauritius and many oceanic islands (including Hawaii)
Spermacoce sintenisii (Urb.) Alain - synonym of Spermacoce brachysepala^[3]
Spermacoce tenuior L. - slender false buttonweed - Texas, Louisiana, Georgia, West Indies; Latin America from Mexico to Bolivia; naturalized in Tanzania, Java, Sulawesi and Galápagos
Spermacoce terminalis (Small) Kartesz & Gandhi - synonym of Spermacoce neoterminalis^[3]
Spermacoce tetraquetra A. Rich. - pineland false buttonweed - Florida, West Indies, Mexico, Central America
Spermacoce verticillata L. - shrubby false buttonweed - Florida, West Indies, most of Latin America; naturalized in Africa, Australia, assorted oceanic islands

References

^ "Spermacoce L." Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2023-03-18.
^ USDA, NRCS (n.d.). "Spermacoce". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 25 November 2015.
^ ^a ^b ^c ^d ^e ^f ^g ^h Kew World Checklist of Selected Plant Families
^ Davidse, G., M. Sousa Sánchez, S. Knapp & F. Chiang Cabrera. 2012. Rubiaceae a Verbenaceae. 4(2): i–xvi, 1–533. In G. Davidse, M. Sousa Sánchez, S. Knapp & F. Chiang Cabrera (eds.) Flora Mesoamericana. Missouri Botanical Garden Press, St. Louis.
^ Alftervista Flora of North America
^ Biota of North America Program