The genus Remijia is classified in the Tribe Cinchoneae, and includes about 40 species of shrubs and small to medium-sized trees found in humid forest vegetation in tropical South America. Remijia can be recognized by the combination of its opposite or often verticillate, frequently well developed leaves, its well developed, ligulate, generally obtuse stipules that are held erect and pressed together in bud, its axillary inflorescences with one to usually several small to medium-sized white to red flowers, and its woody, small to well developed, cylindrical capsules with numerous narrow winged seeds. The flowers are frequently described as fragrant, and the corolla lobes are generally thick and triangular in cross-section at the apices. The capsules usually open from the apex, but in some species they open from the base. In several species of Remijia the plants are unbranched monocaulous shrubs, such as Remijia chelamophylla. Several species of Remijia have young inflorescences enclosed in enlarged bracts, which are often deciduous. Some species of Remijia are notably robust with relatively large leaves, more than half a meter long, such as Remijia ulei. Several species have associations with ants, which live in hollow stems, for example in Remijia ulei, or inflated sacs in the petioles, for example in Remijia physophora. Steyermark (1972) described two species, Remijia argentea and Remijia duckei, as having spathaceous calyx limbs; however in these the calyx limbs are open and denticulate in bud, rather than closed or fused into a cap, and they split irregularly into one, two, or sometimes more segments rather than regularly spsitting down only one side. A number of species of Remijia are found mainly on sandy substrates. The most commonly collected species appears to be Remijia firmula.

Remijia has not been comprehensively reviewed, though Schumann (1889) treated many of the species and Steyermark (1972: 249-269) presented an extensive floristic treatment that covered species found outside his specific study area. Schumann (1891: 149-157) in a genus overview recognized three sections, one of which corresponds now to Ciliosemina. The systematics and relationships of Remijia were studied based on a cladistic analysis of morphological data by Andersson (1995), who included Cephalodendron within its circumscription. When Cephalodendron was described it was considered closely related to Remijia and included two distinctive species of shrubs and small trees from the Guayana Highlands. These species were separated from Remijia based on their capitate inflorescences, which are borne on well developed peduncles; other species of Remijia with capitate and sometimes pedunculate inflorescences were alredy known, such as Remijia physophora, but were not mentioned in the analysis of the separation of these genera. Additionally the two species included in Cephalodendron share a distinctive robust habit, dense pilose or hirsute pubescence, relatively large leaves and stipules, well developed peduncles, and a range at higher elevations in the Guayana Highlands. Andersson (1995) studied the systematics of the tribe Cinchoneae and concluded that Cephalodendron is not distinct and synonymized it with Remijia, but did not make the combinations in Remijia for its two species, Cephalodendron globosum and Cephalodendron aracumuniensis; these combinations were later published by Taylor et al. (2004).

Subsequently Andersson & Antonelli (2005) studied the relationships of Remijia using molecular data, and separated two species of Remijia into the new genus Ciliosemina: the commonly collected species Remijia pedunculata and also Remijia purdieana. They distinguished Ciliosemina by its seeds with ciliate to fimbriate wing margins, vs. entire to serrulate or shortly irregular in Remijia. The genus description presented by Andersson (1994) included Ciliosemina pedunculata, and largely applies to this species rather than other Remijia species especially as to the fruits and seeds.

Remijia is similar to Cinchona and Ladenbergia, which are found in montane tropical South America and Ladenbergia also ranges into the Amazon basin; both of these other genera can be separated by their opposite leaves and terminal inflorescences. Some species of Remijia with capsular fruits that open from the base were confused with Cinchona in particular when Cinchona was distinguished based on its capsular fruits with this form of dehiscence, but Andersson (1995) demonstrated that all three of these genera have variation in this feature and the mode of capsule dehiscence does not distinguish or characterize any of them. Remijia has also been confused with Macrocnemum, but Macrocnemum differs in its terminal or pseudoaxillary inflorescences, pink corollas with the lobes reduplicate-valvate in bud, and capsules with marginal loculicidal dehiscence, which have valves that remain fused together and each open longitudinally along one side.

Remijia is also quite similar to Maguireocharis, and these genera are closely related (and perhaps not distinct). Maguireocharis includes one species found in the Guayana Highlands, and was distinguished from Remijia based on its corollas that are pubescent internally and its pubescent anthers, vs. apparently the corollas glabrous internally and anthers pubescent in Remijia although not all of its species have been surveyed for these features. Overall Maguireocharis is very similar to Remijia morilloi and Remijia grazielae, which are found in the same general region though at lower elevations.

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

• Andersson, L. 1995. Tribes and genera of the Cinchoneae complex (Rubiaceae). Ann. Missouri Bot. Gard. 82(3): 409–427.
• Taylor, C. M., J. A. Steyermark, P. G. Delprete, A. Vincentini, R. Cortés-Ballén, D. C. Zappi, C. H. Persson, C. B. Costa & E. Anunciação. 2004. Rubiaceae. 8: 497–847. In J. A. Steyermark, P. E. Berry & B. K. Holst (eds.) Fl. Venez. Guayana. Missouri Botanical Garden Press, St. Louis.
• Andersson, L. & A. Antonelli. 2005. Phylogeny of the tribe Cinchoneae (Rubiaceae), its position in Cinchonoideae, and description of a new genus, Ciliosemina. Taxon 54(1): 17–28.
• Andersson, L. 1994. Tribe 1. Cinchoneae. 50: 1–82. In G.W. Harling & L. Andersson (eds.) Fl. Ecuador. University of Göteborg, Göteborg.
• Steyermark, J. A. 1972. Rubiaceae. 23: 227–832. In B. Maguire & Collaborators (eds.) Bot. Guyana Highl.—Part IX. Mem. New York Bot. Gard. New York Botanical Garden Press, Bronx.
• Schumann, K. 1889. Rubiaceae [III]. 6(6B): 125–442, t. 94–151. In C. F. P. von Martius (ed.) Fl. Bras. F. Fleischer, Monachii & Lipsiae.
• Schumann, K. M. 1891. Rubiaceae. 4(4): 1–194. In H. G. A. Engler & K. Prantl (eds.) Nat. Pflanzenfam. Engelmann, Leipzig.