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]
^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. S2CID23714607.
^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.
^Quattrocchi U (2000). CRC World Dictionary of Plant Names. Vol. 1. Boca Raton, New York, Washington DC, London: CRC Press. ISBN978-0-8493-2675-2.
^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. PMID20382247.
^"Exostema (Pers.) Bonpl". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2023-03-19.