Chione includes one rather variable Neotropical species found in wet forest vegetation in Mexico, the Antilles, and northwestern South America. Chione is characterized by its shrub or small tree habit, its small ovate interpetiolar stipules that held erect and pressed together in bud and are quickly deciduous, its petiolate medium-sized to somewhat small leaves that often have small pit-type domatia tucked into the axils of the secondary veins on the undersurface, terminal inflorescences that are cymose and pedunculate, pedicellate homostylous flowers with short truncate to lobed calyx limbs, its tubular white corollas with four to six imbricated obtuse lobes, its exserted anthers and stigmas, and its somewhat large fleshy fruits that are red to purple and contain one large hard stone or pyrene. The higher-order venation is often not very evident on the leaves, and the domatia are much more frequently developed on vegetative leaves than on the leaves on flowering stems. Taylor (2003) noted that the wood often oxidizes purple when cut or damaged. The flowers are protandrous and fragrant during the day, and apparently pollinated by insects. The stamens are inserted in the corolla near its base. The fruits are ellipsoid to ovoid and often pendulous on the plants, and the pyene has two locules and seeds. Chione lacks raphide crystals. Its relationships within the Rubiaceae are not yet clear. In the molecular phylogeny of Bremer & Eriksson (2009), Chione was found to belong to the subfamily Cinchonoideae, and to be a sister group to the Neotropical tribes Hamelieae and Hillieae. They did not classify Chione in any tribe. Chione was studied comprehensively and a taxonomic revision published by Taylor (2003). This genus was long characterized as restricted to Mesoamerica and the Antilles, but field work in the Andes has now documented Chione as far south as central Peru.

Chione plants without fruits or well developed flowers are rather nondescript, and this genus is often overlooked. The stipules are distinctive but very quickly deciduous so many specimens lack them. The small pit domatia on the leaves aid identification but are not always present. Chione is sometimes confused with Psychotria, which has valvate corolla lobes and 1-locular hemispherical or triangular pyrenes. Chione is also sometimes confused with Guettarda and Chomelia, especially when in fruit, but these have imbricated stipules and usually also evident closely reticulated tertiary or quaternary venation with regularly shaped areoles, quadrangular in Guettarda and narrowly rectangular in Chomelia.

The circumscription of Chione was somewhat problematic until Taylor (2003, two articles) clarified that several species have been inaccurately included there. He excluded two Antillean species based on morphological analysis, Chione exserta and Chione seminervis. These two species have stipules that are interpetiolar, trianguar to elliptic, persistent to usually deciduous, and imbricated in bud. After dehiscence he stipules of these species characteristically remain somewhat connected across the interpetiolar portion, forming a loose tube similarly to the stipules of Psychotria carthagenensis. Colleteria also differs from Chione in its reportedly white fruits with two plano-convex pyrenes. Also excluded from Chione was Chione darienensis, which is now considered a member of the tribe Guettardeae and called Stenostomum darienense.

Several well marked species have been recognized in Chione, but Taylor (2003) demonstrated that while several of these have distinct geographic ranges, they are not entirely separable morphologically. He therefore recognized one species of Chione, Chione venosa, with four varieties. Chione venosa var. venosa is the most widely distributed and most commonly collected variety, and is found almost throughout the range of the genus. Subsequently Borhidi in his study of Mexican Rubiaceae treated the Mexican plants as two subspecies, rather than varities, but did not address the taxonomic status of the other varieties recognized by Taylor. Those other varities are similarly distinct morphologically, ecologically, and geographically and all the varieties sere noted by Taylor to have a similar taxonomic status, so treating these as two subspecies and two varieties produces an inconsistent taxonomy and is not done here.

Author: C.M. Taylor.
The content of this web page was last revised on 15 May 2020.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml

• Taylor, D. W. 2003. A taxonomic revision of the genus Chione (Rubiaceae). Syst. & Geogr. Pl. 73(2): 171–198.
• Bremer, B. & T. Eriksson. 2009. Time tree of Rubiaceae: Phylogeny and dating the family, subfamilies, and tribes. Int. J. Pl. Sci. 170(6): 766–793.
• Taylor, D. W. 2003. Colleteria (Rubiaceae), a new genus from the Caribbean. Syst. & Geogr. Pl. 73(2): 199–208.