Carolus anderssonii (W. R. Anderson) W. R. Anderson—Western Ecuador (Manabí, Guayas, Loja) and northwestern Peru (Piura, Lambayeque, Cajamarca). Petiole eglandular or bearing 2 small knoblike glands at apex; lamina eglandular or bearing small marginal glands near base, adaxially soon glabrate, abaxially densely and persistently silvery-metallic-sericeous; stipules very small, triangular, interpetiolar, ± persistent; inflorescence a short, dense, axillary or terminal panicle with the flowers ultimately borne in umbels of 4 (–6); peduncles 1–2.5 mm long; sepals all eglandular or the lateral 4 bearing large paired abaxial glands; lateral petals subentire or denticulate, posterior petal short-fimbriate; anthers glabrous, the connective red to black; styles dorsally short-apiculate at apex; samara tomentose on nut, sericeous to glabrescent on wings, with a well-developed rectangular or triangular dorsal wing between lateral wings, (2–) 3–7 mm wide.
Carolus chasei (W. R. Anderson) W. R. Anderson—Bahia and Pernambuco, Brazil. Petiole eglandular; lamina up to 7 cm long and 3.5 cm wide, mostly smaller, eglandular or bearing 1–3 tiny glands embedded in margin in proximal third, adaxially glabrate at maturity, abaxially densely and persistently sericeous (occasionally glabrescent in age); stipules minute, triangular, interpetiolar, caducous; inflorescence an axillary pseudoraceme of 4–10 flowers, shorter than subtending leaf, with internodes developed between pairs of flowers and the pairs ± evenly distributed; pedicels mostly raised on well-developed peduncles, distal flowers occasionally with pedicel subsessile; lateral 4 sepals bearing large paired abaxial glands, the anterior eglandular; petals fimbriate or glandular-fimbriate all around margin of limb; anthers glabrous, the connective brownish; styles dorsally apiculate or short-hooked at apex; samara tomentose or sericeous on nut, sericeous on wings, smooth between lateral wings, the dorsal winglet completely lacking or represented at most by a rounded hump at apex.
Carolus chlorocarpus (Adr. Juss.) W. R. Anderson—Central and eastern Bolivia, northeastern Paraguay, and southeastern Brazil. Petiole eglandular or biglandular between middle and apex; lamina of larger leaves 6–11.5 cm long and (1.5–) 2–4.5 cm wide, eglandular or bearing several tiny glands on or embedded in margin in proximal third, originally tomentose or loosely sericeous but soon glabrate on both sides; stipules minute, triangular or subulate, interpetiolar, often soon deciduous; inflorescence axillary, mostly unbranched but occasionally paniculate, the pseudoracemes containing 6–14 (–20) flowers, shorter than subtending leaf, with internodes developed between pairs of flowers and the pairs ± evenly distributed; pedicels mostly raised on well-developed peduncles; sepals all eglandular or the lateral 4 bearing large paired abaxial glands; petals dentate or fimbriate, the divisions not glandular-thickened; anthers glabrous, the connective brownish or red; styles dorsally acute or apiculate at apex; samara tomentose on nut, sericeous on wings, usually smooth between lateral wings with the dorsal wing absent or represented by a rib, sometimes with a rounded hump at apex. Two collections from Bolivia (Bang 1192 and Lewis 37767) have a dorsal winglet on the samara, 1–4 mm wide. I am choosing not to give this variant taxonomic recognition at this time, but there is a name available—Bang 1192 is the type of Mascagnia chlorocarpa var. cristata Nied.
Carolus dukei (Cuatrec. & Croat) W. R. Anderson—Known only from the type, collected in Panama. Petiole eglandular or bearing 2 small knoblike glands at apex; lamina eglandular, adaxially glabrous at maturity, abaxially densely and persistently silvery-metallic-sericeous; stipules not found; inflorescence a compact axillary panicle much shorter than subtending leaf, with the flowers borne ultimately in umbels of 4; pedicels sessile or subsessile, the peduncles up to 0.5 mm long; lateral 4 sepals bearing large paired abaxial glands, the anterior eglandular; petals not known; anthers glabrous; styles with a dorsal hook at apex 0.2 mm long; samara appressed-tomentose, nearly smooth between lateral wings, the dorsal wing represented only by a longitudinal rib and a triangular winglet up to 1.5 mm high and wide at apex.
Carolus renidens (Adr. Juss.) W. R. Anderson—I have seen this species only from the vicinity of Rio de Janeiro, Brazil; Niedenzu (1928) cited two collections (under Tetrapterys heteropetala) from Espírito Santo. Petiole eglandular or bearing 2 small knoblike glands at apex; lamina of larger leaves mostly at least 9 cm long and 4 cm wide, often larger, eglandular or bearing several small glands on margin near base, adaxially glabrate at maturity, abaxially densely and persistently metallic-sericeous; stipules small, triangular, borne on stem between petioles, persistent or deciduous in age; inflorescence an axillary or terminal panicle composed of pseudoracemes of 6–20 flowers; pedicels raised on well-developed short to long peduncles; sepals all eglandular or the lateral 4 bearing large paired abaxial glands; posterior petal glandular-fimbriate all around margin of limb, the lateral petals fimbriate or dentate; anthers bearing a few spreading hairs on locules, the connective black; styles dorsally rounded, truncate, or short-apiculate at apex; samara tomentose on nut and sericeous on wings, bearing between lateral wings ca. 5 parallel ± dissected winglets 1–2.4 mm wide. There is at P a sheet of "Claussen 77" supposedly from Minas Gerais, but Niedenzu (1928, p. 195) cited Claussen 77 as coming from Nova Friburgo, Rio de Janeiro. In the same place Niedenzu cited "Claussen s.n." from Minas Gerais, presumably on the basis of the specimen in B shown in F neg. 12746. Given the evident confusion, I am assuming that Claussen collected this species only in Rio de Janeiro, not in Minas Gerais.
Carolus sinemariensis (Aubl.) W. R. Anderson—Southern Mexico, Central America, Lesser Antilles (Grenada and St. Vincent), and northern South America (northern Peru, eastern Ecuador, Colombia, Venezuela, Guyana, and French Guiana and adjacent Brazil). Petiole eglandular or bearing 2–4 (–6) small glands on distal 3/4; lamina bearing several to many tiny glands embedded in the margin or slightly adaxial to it and distributed from base to (often) near apex, originally sericeous or appressed-tomentose but soon glabrate on both sides, rarely thinly hairy below at maturity; stipules small, triangular, interpetiolar, persistent or deciduous in age; inflorescences axillary or axillary and terminal, compact, unbranched or paniculate, with the flowers crowded distally in umbels, corymbs, or very dense pseudoracemes of 4–8 (–12); pedicels raised on short but evident peduncles; sepals rounded, the lateral 4 bearing large paired abaxial glands, the anterior eglandular; petals dentate or the posterior short-fimbriate with the fimbriae ± glandular-thickened in southern populations; anthers glabrous or bearing a few hairs on connective, the connective brown or red; styles dorsally rounded, truncate, or acute at apex, terete or laterally flattened; samara sericeous or tomentose, mostly butterfly-shaped with 2 well-developed lateral wings but reduced or modified in some populations (see discussion below), with a dorsal crest or winglet and usually smooth between lateral wings and dorsal crest. This species (or species-complex) is exceedingly variable, especially in its fruits. Throughout most of its range the butterfly-shaped samara is similar, although varying significantly in size. However, in the Guianas and adjacent Brazil the samara looks as if it has been modified for dispersal by water, with the lateral wings represented by two long, narrow, swept-back projections (French Guiana) or reduced to corky outgrowths on an enlarged nut (Guyana and Brazil). Those plants are otherwise typical of the species in vegetative and floral characters, so it is difficult to segregate them taxonomically, especially the ones in which the samaras are reduced to an intermediate degree. The other area of extreme variation is the Yucatán peninsula and northern Central America, where many populations have small leaves and small mericarps with very short lateral wings and, sometimes, low outgrowths between the lateral and dorsal wings. Much as I would like to give those plants taxonomic recognition, I find after examining many specimens that intermediates and lack of correlation of the derived character-states make that impossible. For that reason, I am continuing for now to recognize this species in a very broad sense, knowing how unsatisfactory that will seem to anyone who compares a "typical" representative with one of the plants with reduced mericarps. Looking toward the time when someone may attempt to divide up this complex, I can offer these comments on available names: The oldest name, Banisteria sinemariensis Aubl., was based on a type from French Guiana, where the species is very rare. The type was in flower. The only two fruiting specimens I have seen from French Guiana have the highly modified fruits described above, so it seems likely that the epithet sinemariensis will go with that form if the species is subdivided. The next available name, Malpighia volubilis Sims, was based on a flowering type grown from seeds from the "West Indies." All known fruiting collections from the Lesser Antilles have large "normal" samaras, so if those seeds really came from the West Indies the epithet volubilis will probably be taken up for the vast majority of populations, including the types of Hiraea schizoptera Turcz. and Mascagnia hondensis C. V. Morton. The populations in Guyana and adjacent Brazil with reduced mericarps have a name, Diplopterys microcarpa Sandwith. However, there is no name available for the form in the Yucatán and northern Central America. Those plants have been called "Mascagnia polycarpa Brandegee," but the type of that name represents a species of Psychopterys.