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Published In: Publications of the Field Museum of Natural History, Botanical Series 11(5): 180. 1936. (Publ. Field Mus. Nat. Hist., Bot. Ser.) Name publication detailView in Biodiversity Heritage Library

Project Name Data (Last Modified On 10/6/2009)
Acceptance : Accepted
Project Data     (Last Modified On 9/26/2016)

Amphidasya Standl. includes at least 13 species of low shrubs and suffrutescent herbs found in wet neotropical forests of Central America and northern South America. The genus distribution is centered in the Chocó biogeographic region, with another center in montane regions of Venezuela. (Didymochlamys has a generally similar geographic distribution.) Amphidasya can be recognized by its opposite, often clustered and rather large leaves; its interpetiolar stipules that are usually deeply laciniate to fimbriate; its flowers that are grouped in pseudoaxillary (i.e., lateral) cymes; its salverform white corollas with slender long tubes; and its fleshy to dry, rather small fruits. The flowers are homostylous, and nocturnal in at least some species. The anthers usually have the connective prolonged into an apical appendage. The corolla lobes are valvate in bud, and are often ornamented with multicellular, tuberculate to filamentous appendages that are borne on the margins and sometimes also their adaxial (i.e., internal) faces of these lobes. In many species the calyx lobes persist on the fruits and enlarge markedly as they develop. The stipules that are deeply divided into narrow segments are unusual in Rubiaceae and distinctive. The corollas are white and variable in size, and apparently the flowers are nocturnal.

Amphidasya was separated out from Sabicea Aubl. by Standley in 1936, but then was still classified by most authors together with Sabicea in the tribe Isertieae of the subfamily Cinchonoideae. However, the tissues of Amphidasya contain raphides, while other genera of Isertieae lack these. Recent studies based on molecular data found that Amphidasya is related to the neotropical genus Raritebe and to several paleotropical genera, notably Pauridiantha, and Amphidasya is now classified in the tribe Urophylleae of the subfamily Rubioideae (Smedmark et al., 2008; Bremer & Eriksson 2009).

The circumscription and species taxonomy of Amphidasya were reviewed recently by Steyermark (1972, pp. 316-312), Andersson & Ståhl (1999), and Taylor & Clark (2001); the key to the species of Amphidasya included below is that of Taylor & Clark (2001: pp. 490-491). Amphidasya is similar to Sommera and Tammsia, which have lineolate venation or fiber bundles in the leaves and fleshy baccate fruits.

Author: C.M. Taylor.
The content of this web page was last revised on 8 December 2010.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml



Neotropical: wet lowland to premontane forests, Nicaragua to Peru, and to eastern Venezeula and adjacent Brazil.  



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            Low shrubs or subshrubs, often unbranched, terrestrial, unarmed. Leaves opposite, petiolate, venation not lineolate; stipules interpetiolar, persistent, generally erect and flatly appressed in bud, entire or usually deeply multifid to laciniate with 5--17 narrow segments. Inflorescence pseudoaxillary and/or terminal, sessile to pedunculate, few- to several flowered, cymose to subcapitate, bracteate, the bracts entire to multifid. Flowers sessile to shortly pedicellate, small to medium-sized, homostylous, protandrous, rather showy, at least sometimes nocturnal. Hypanthium oblong to turbinate. Calyx limb deeply lobed, lobes (4)5, well developed, narrow to spatulate or obovate, sometimes unequal but without calycophylls. Corolla slenderly salverform with the tube usually well developed, white, internally glabrous, lobes 5, valvate in bud, on their margins and/or adaxial surface frequently verruculose or verrucose. Stamens 5, inserted in the upper part of the corolla tube; anthers linear, dorsifixed near the base, included, sometimes with the connective prolonged into a linear apical appendage. Ovary 2-locular; ovules numerous in each locule, on axile placentas. Fruit baccate, subglobose to ellipsoid, fleshy, apparently green, with the calyx lobes persisting and frequently enlarging markedly as the fruits develop. Seeds small, angled to subglobose, reticulate.

            Nicaragua, Costa Rica, Panama, Colombia, Venezuela, Ecuador, Peru, northern Brazil; ca. 15 species, 2 in Venezuela, 1 of these in the flora area.


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1. Stipules entire; erect branched shrubs.....Amphidasya venezuelensis

1'. Stipules laciniate; herbs, low sparsely branched shrubs, or unbranched shrubs.

    2. Calyx lobes 4, stipitate, with an ovate to lanceolate limb on a narrow stipe-like basal portion.....Amphidasya spathulata

    2'. Calyx lobes 4, narrowly triangular to triangular, elliptic, oblanceolate, ligulate, or obovate, without a stipe-like basal portion.

        3. Leaf blades oblanceolate to obovate, widest above the middle, at base acute to acuminate.

            4. Calyx lobes at anthesis 15-24 mm long, linear to narrowly oblanceolate, acute to acuminate; stipules with the stipule body (i.e., the undivided basal portion) 2-12 mm long...Amphidasya ambigua

            4. Calyx lobes at anthesis 6-15 mm long, narrowly triangular to narrowly oblanceolate, narrowly ligulate, obovate, or spathulate; stipules with the stipule body 1-4 mm long.

                5. Inflorescences subsessile; calyx lobes acute to acuminate.....Amphidasya longicalycina

                5'. Inflorescences with peduncles 0.5-2 cm long; calyx lobes acute to obtuse, rounded, or truncate.

                    6. Stipule lobes 5-13 mm long; western Colombia to Amazonian Peru....Amphidasya colombiana

                    6'. Stipule lobes 4-5.5 mm long; Sierra de la Neblina, Venezuela....Amphidasya neblinae

        3'. Leaf blades elliptic, elliptic-oblanceolate, narrowly elliptic, elliptic-oblong, or ovate, widest variously below, at, or just above the middle, at base truncate, obtuse, rounded, cuneate, or acute but not or only shortly acuminate along petiole;

            7. Corolla tube ca. 8 mm long; stipules with the stipule body (i.e., the undivided basal portion) 0.5-2 mm long and with 1-3 lobes....Amphidasya amethystinae

            7'. Corolla tube 11-42 mm long (but unknown in Amphidasya brevidentata); stipules with the stipule body 1-15 mm long and with 4-11 lobes.

                8. Stipules with the stipule body 2 or more times as long as the lobes....Amphidasya brevidentata

                8'. Stipules with the stipule body about half as long or less as the lobes.

                    9. Corolla tube 11-15 mm long; calyx lobes at anthesis oblanceolate, obovate, or spathulate, 0.8-4 mm wide.

                        10. Leaves with secondary veins 10-15 pairs; corolla tube 13-15 mm long....Amphidasya colombiana

                        10'. Leaves with secondary veins 16-18 pairs; corolla tube 11-11.5 mm long....Amphidasya intermedia

                    9'. Corolla tube 25-42 mm long; calyx lobes at anthesis linear to narrowly elliptic, narrowly ligulate, narrowly triangular, or oblanceolate, 0.5-15 mm wide.

                        11. Calyx lobes at anthesis 9-10 mm long; corolla lobes smooth on the margins and adaxial surfaces.....Amphidasya umbrosa

                        11'. Calyx lobes at anthesis 9-19 mm long; corolla lobes markedly verruculose on the margins and adaxial surfaces, sometimes these projections giving the appearance of laciniate.

                            12. Corolla tube 36-40 mm long; eastern and central Panama.....Amphidasya panamensis

                            12'. Corolla tube 25-30 mm long; northwestern South America.

                                13. Corolla in bud acute to acuminate at apex; leaves with secondary veins 10-16 pairs.....Amphidasya bullata

                                13. Corolla in bud truncate at apex; leaves with secondary veins 22-30 pairs.....Amphidasya elegans



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