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Published In: Enumeratio Systematica Plantarum, quas in insulis Caribaeis 2, 16. 1760. (Enum. Syst. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library

Project Name Data (Last Modified On 12/5/2012)
Acceptance : Accepted
Project Data     (Last Modified On 4/9/2020)

Hamelia includes 16 species of shrubs found in humid to very wet forests and secondary vegetation, from lowlands to montane regions, from México, Central America, southern Florida, and the Antillas to Bolivia and Argentina. The species richness of the genus is centered in southern Mexico, northern Central America, and the Greater Antilles. One species, Hamelia patens, is found across the range of the genus; another, Hamelia axillaris, has a distribution nearly as broad; and other species are found from Central America to the western Amazon basin. Hamelia can be recognized by its generally woody habit; triangular (or rarely 3-lobed, Hamelia xorullensis), generally persistent stipules; petiolate leaves that are opposite to verticillate; terminal, basically cymose inflorescences; bisexual, homostylous flowers with five calyx lobes, five stamens, and showy corollas red, orange, or yellow corollas with five imbricate lobes; ovaries with five locules; stigmas that are simple or five-lobed; and succulent berry fruits that become purple-black at maturity and contain numerous angled seeds. The corolla lobes are often relatively very short compared to the tubes. The inflorescence axes in many species are generally dichotomous intially, and continue developing over the following weeks and become prolonged and markedly helicoid as the fruits develop. Hamelia patens is perhaps the most widespread and commonly collected species of Neotropical Rubiaceae.

Hamelia was revised by Elias (1976), and this revision still stands as generally comprehensive; in contrast to most genera of Neotropical Rubiaceae, no new species have been described since this was published, and the geographic distributions of only a few species have been expanded. The good knowledge of this genus by 1976 is due at least in part to the plants being showy, frequent locally, and in many species, found in secondary vegetation and flowering more or less continually. Most of the species are found in wet vegetation, but Hamelia patens ranges into seasonal vegetation and has been cultivated world-wide in tropical regions for some time; in recent years it has also been cultivated in butterfly houses, where it provides a good year-round food source, and as seasonal plants in temperate regions where some cultivars are grown as pot plants.

Hamelia belongs to the tribe Hamelieae, which has several genera with their centers of diversity in southern Mexico and Central America, along with some small genera that are endemic to this region. Elias (1976) recognized two sections within Hamelia: Sect. Hamelia is diagnosed by its red, orange, or yellow corollas that are tubular at anthesis (that is, with the diameters at the base and the throat equal), and Sect. Amphituba, which is diagnosed by its yellow corollas often with a characteristic form, tubular in the short basal portion and then abruptly flared at the top of this tube, with the upper portion funnelform or flaring. Plants of Hamelia can be difficult to identify to section and species that differ mainly in their corolla form can be difficult to separate, because the corolla buds are tubular in all of the species with those of Sect. Amphituba generally dilating only when the flowers open. Elias included either species in Sect. Hamelia and eight species in Sect. Amphituba; each section includes at least one species that ranges to the Amazon basin, and sect Amphituba includes several. Hamelia versicolor of sect. Hamelia and Hamelia xorullensis of sect. Amphitiba, both of western Mexico, are found in the dryest vegetation of any species in the genus. Hamelia ventricosa of sect. Amphituba has the largest flowers of the genus, with corollas 30-56 mm long.

Hamelia is sometimes confused with Palicourea; however Palicourea can be separated by its bilobed stipules, corollas generally with an asymmetrically swollen base, 2-lobed stigmas, and fruits with two pyrenes. In the species of Hamelia with orange or red flowers, the corollas often become darkened after anthesis but remain on the plant another day or so. Good dried specimens of Hamelia patens are somewhat difficult to make, because the plants characteristically drop their leaves rapidly in response to heat or water stress, including pressing.

Author: C.M. Taylor
The content of this web page was last revised on 9 April 2020.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml

Distribution: Wet to seasonal forest vegetation, 0-1800 m, central Mexico through Central America, and in southern Florida and the Antilles to northwestern South America, with one species also ranging to Bolivia and northern Argentina.


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Shrubs and small trees, unarmed, terrestrial, with raphides in the tissues. Leaves opposite or in verticils of 3--5, petiolate, entire, with the higher-order venation not lineolate, sometimes with pubescent domatia; stipules interpetiolar, linear to triangular or ovate, erect and apparently valvate in bud, persistent or caducous. Inflorescences terminal or sometimes later displaced to pseudoaxillary, cymose to thyrsiform with axes often monochasial and prolonged, few- to multiflowered, pedunculate, bracteate. Flowers sessile to pedicellate, bisexual, homostylous, apparently protandrous, medium-sized to rather large, perhaps sometimes fragrant, apparently diurnal; hypanthium ellipsoid to turbinate; calyx limb reduced to developed, subtruncate to 5-lobed, without calycophylls; corolla tubular or funnelform, yellow, orange, or red, glabrous inside, lobes 5, triangular and usually short, imbricated (quincuncial) in bud, without appendages; stamens 5, inserted in lower part of corolla tube or near its base, anthers oblong, dorsifixed, dehiscent by linear slits, included or partially exserted, without appendages; ovary (4)5-locular, with ovules numerous in each locule, on axile placentas, stigma 1, oblong-cylindrical, smooth or 5-ridged, included. Fruit baccate, subglobose to ovoid or lanceoloid, fleshy or juicy, generally becoming red then purple-black, with calyx limb persistent; seeds numerous, small (0.2--1.2 mm), irregularly flattened to angled, foveolate. 


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Key to Species of Hamelia; by C.M. Taylor, based on Elias (1976)

1. Corolla infundibular or dilated, expanding gradually or abruptly toward the apex, yellow...Sect. Amphituba

   2. Corolla tube 11-13 mm long, 3-5 mm wide at top; inflorescence a generally congested or compact dichasium, sometimes becoming lax in fruit; fruits 5-7 mm long; Central America and the Antilles to Bolivia.....Hamelia axillaris

   2'. Corolla tube 18-50 mm long, 4-20 mm wide at top; inflorescence a somewhat congested to lax dichasium or cyme; fruits 7-16 mm long; Mexico and the Greater Antilles to Ecuador. 

      3. Calyx lobes 3-5 mm long, elliptic-oblong to oblanceolate; stipules subulate; Central America and northwestern South America....Hamelia calycosa

      3'. Calyx lobes 0.2-2.5 mm long, ovate, triangular, lanceolate, or elliptic-oblong; stipules tirangular to lanceolate. 

         4. Leaves, calyx, and corolla scabrous; Jamaica...Hamelia papillosa 

         4'. Leaves, calyx, and corolla glabrous to tomentose or villous; Mexico and the Antilles to Ecuador. 

            5. Calyx lobes apiculate; fruits 7-9 mm long; stipules 1-2 mm long; pedicels 4-9 mm long; Greater Antilles...Hamelia cuprea

            5'. Calyx lobes acute but not apiculate; fruits 9-12 mm long; stipules 1.5-6 mm long; flowers sessile or with pedicels to 4 mm long; Mexico to Ecuador and Antilles. 

               6. Corolla tube flared or dilated gradually, 4-7 mm broad at top; inflorescence axes ascending, 8-26-flowered; Nicaragua to Colombia...Hamelia xerocarpa

               6'. Corolla tubular at base then abruptly expanded, the tube 10-20 mm broad at top; inflorescence axes spreading to ascending, 4-14-flowered; Mexico to Ecuador and Antilles. 

                  7. Corolla 23-31 mm long; leaves 7.5-27 x 4-14.2 cm, with 11-14 pairs of secondary veins; inflorescence mainly dichasial, 20-200-flowered; Costa Rica to Ecuador....Hamelia macrantha 

                  7'. Corolla 31-50 mm long; leaves 4.5-14 x 1.7-4.6 cm, with 6-10 pairs of secondary veins; inflorescence scorpioid or helicoid, 6-24-flowered; Mexico, Jamaica.

                    8. Leaves glabrescent below; stipules triangular; corolla glabrous externally; fruit subcylidrical or lanceoloid; Jamaica...Hamelia ventricosa

                    8'. Leaves densely tomentose below; stipules 3-lobed, generally asymmetrically; corolla tomentose externally; fruit ellipsoid to subglobose; western Mexico....Hamelia xorullensis

1'. Corolla strictly tubular or cylindrical, not expanding toward apex, yellow, orange, or red....Sect. Hamelia

   9. Inflorescence a reduced dichasium, borne on short lateral branchets, 3-5(-9)-flowered; leaves 1.5-8.7 x 0.8-4.8 cm, with 3-5 pairs of secondary veins; Panama.....H. sanguinea

   9'. Inflorescence a dichasium. compound dichasium, cyme, or thyrse, terminal on main stems, 10-200-flowered; leaves 4.2-26 x 1.5-11 cm, with 3-11 pairs of secondary veins; Mexico, southern Florida, and the Antilles to Argentina. 

      10. Flowers and/or fruits not or weakly secund on inflorescence axes; stipules 1.5-2 mm long, subular to narrowly triangular; plants of Mexico and Jamaica. 

         11. Flowers pale to coppery yellow; peduncle 0.5-1 cm long; stipules subulate, persistent; leaves opposite; seeds 0.7-0.9 mm long; Jamaica....Hamelia chrysantha

         11'. Flowers orange to red; peduncle 1.7-4.2 cm long; stipules narrowly triangular, caducous; leaves opposite or verticillate; seeds 1-1.2 mm long; Mexico....Hamelia versicolor

      10'. Flowers and/or fruits not to markedly secund on inflorescence axes; stpules 2.2-7 mm long, linear to triangular; Mexico, southern Florida, and the Antilles to Argentina. 

         12. Inflorescence axes, calyx, and corolla densely hirtellous to villous; leaves sparsely to densely hirtellous to villous below. 

            13. Calyx lobes ovate, 0.5-1 mm long; leaves with secondary veins generally 7-10 pairs; seeds 0.6-0.9 mm long; common, Mexico, southern Florida, and the Antilles to Argentina....Hamelia patens 

            13'. Calyx lobes narrowly oblong to triangular, 1-4 mm long; leaves with secondary veins 3-5 pairs; seeds 1-1.2 mm long; occasional, Caribbean coast of southern Mexico and Central America to Panama....Hamelia rovirosae

         12. Inflorescence axes, calyx, corolla, and leaves glabrous to puberulous, or more densely pubescent on costa and veins and/or with hirtellous domatia in abaxial axils of the secondary leaf veins. 

            14.  Flowers all with well developed pedicels 6-12 mm long; petioles 4-6 cm long; southern Mexico to Nicaragua....Hamelia longipes

            14'. Flowers sessile or with shorter pedicels, to 1.5 mm long; petioles 0.6-5.5 cm long; Mexico, southern Florida, and the Antilles to Argentina. 

               15. Inflorescence a compound, many-flowered dichasium; corolla yellow, tube 10-12 mm long, lobes 1.5-2 mm long; leaves with 11-16 pairs of secondary veins; seeds 0.4-0.5 mm long; Pacific coast of Costa Rica and western Panama.....Hamella magnifolia

               15'. Inflorescence in several-flowered dichsia; corolla orange to red or occasionally yellow, tube 12-22 mm long, lobes 1.3-3.5 mm long; leaves with 6-10 pairs of secondary veins; seeds 0.5-0.9 mm long; Mexico, southern Florida, and the Antilles to Argentina. 

                 16. Leaves with tufted-sericeous pubescence along costa on lower surface; pedicels 0.2-1.3 mm long; corollas yellow or yellow-tinged, with lobes 2.5-3.5 mm long; southern Mexico and Guatemala.....Hamelia barbata

                 16'. Leaves glabrous to puberulous below; flowers sessile or with pedicels to 1 mm long; corollas orange, red, or occasionally yellow, with lobes 1.3-2.5 mm long; Mexico, southern Florida, and the Antilles to Argentina....Hamelia patens


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