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Published In: Enumeratio Systematica Plantarum, quas in insulis Caribaeis 3, 18. 1760. (Aug--Sep 1760) (Enum. Syst. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library

Project Name Data (Last Modified On 10/11/2009)
Acceptance : Accepted
Project Data     (Last Modified On 11/1/2018)

Hillia Jacq. includes about 25 species of succulent, usually epiphytic shrubs and small trees distributed widely in the New World tropics. Hillia plants are found in wet tropical forests, from low to montane elevations. The genus can be recognized by its combination of well developed, interpetiolar, oblanceolate to obovate stipules that are held erect and flattened together in bud, its succulent leaves with the secondary venation usually not visible, its usually relatively large corollas with well developed tubes and 4-10 lobes that are convolute in bud, and its cylindrical woody capsules that contain numerous flat papery seeds with a tuft of silky filaments 1-3 cm long on one end. The seeds are apparently wind-dispersed; a similar arrangement, with a tuft of trichomes at one end, is found in one other genus of neotropical epiphytes, Didymochlamys Hook.f. The flowers vary from salverform to broadly tubular, and range from diurnal and red to nocturnal and white, green, or yellow-green. At in least the species with white nocturnal flowering the flowers last for one night. This genus belongs to the tribe Hillieae. Hillia parasitica is the most commonly collected species.

Species of Hillia can be confused with those of Cosmibuena Ruiz & Pav.; however Cosmibuena differs in its stipules that are shortly united around the stem (vs. separate in Hillia) and its seeds without Hillia's tuft of filaments. Hillia was monographed by Taylor (1994), who included in it the Central American genus Ravnia (Taylor, 1989) and recognized five subgenera. Hillia subg. Hillia is found throughout most of the range of the genus and characterized by fragrant noctural flowers that are pollinated by hawkmoths, and have white salverform corollas with five to six lobes and exserted stigmas. Hillia subg. Illustres is found from southern Central America to southeastern Brazil and characterized by apparently noctural flowers pollinated by bats or perhaps moths, with green or dull orange to purple funnelform corollas with generally six lobes. Hillia subg. Andinae comprises one species of the central Andes with small leaves and flowers, and has flowers similar to those of Hillia subg. Hillia except the stigma is included and positioned near the base of the corolla; this species may also be pollinated by hawkmoths but little is known. Hillia subg. Tetrandrae is found in the Antilles and Central America and characterized by fragrant noctural flowers that are pollinated by hawkmoths, with salverform white corollas with four lobes. Hillia subg. Ravnia is found in southern Central America and northwestern Colombia and characterized by apparently diurnal flowers that are pollinated by hummingbirds, with funnelform to swollen corollas with generally six lobes. One species of Hillia subg. Ravnia, Hillia triflora, is unusual in the genus in its inflorescences that usually have two to three cymose flowers and its corollas that are swollen, with the base and mouth narrower than the middle.

Author: C.M. Taylor
The content of this web page was last revised 15 August 2017.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml


Neotropics: Wet lowland to montane forests, including mangroves, Mexico and the Antilles to Bolivia and southeastern Brazil.



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HILLIA Jacq., Enum. Syst. Pl. 3. 1760.

Succulent epiphytic shrubs or small trees, unarmed, glabrous. Leaves opposite, petiolate to subsessile, venation not lineolate and often not visible; stipules interpetiolar, ligulate to oblanceolate, erect and flatly appressed, caducous. Inflorescences terminal, sometimes bracteate, 1(3)-flowered. Flowers large, showy, homostylous, protandrous, diurnal or nocturnal, sometimes fragrant, sessile or pedunculate. Hypanthium cylindrical to ellipsoid. Calyx limb none or deeply 4--10-lobed, without calycophylls; corolla salverform or funnelform to ventricose, red, green, or white, glabrous internally and externally, lobes 4--10, convolute in bud. Stamens 4--7, inserted near top or middle of corolla tube; anthers narrowly oblong, included, dorsifixed near base. Ovary 2-locular; ovules numerous in each locule, on axile placentas. Fruit capsular, cylindric or narrowly oblong, woody, smooth to longitudinally ridged, septicidally dehiscent from the apex. Seeds papery, small, flattened, fusiform, marginally winged and with a tuft of long filaments at the apex.


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Key to the Subgenera of Hillia

1. Corollas funnelform to tubular or inflated, salmon to bright red or green sometimes flushed with yellow, pink, orange, or dull purple.
     2. Corollas funnelform, green sometimes flushed with yellow, pink,orange, or dull purple; Costa Rica to southeastern Brazil... Subg. Illustres (7 species)  

     2'. Corollas funnelform to tubular or inflated in the middle, salmon to bright red; southern Mexico to northwestern Colombia and northeastern Venezuela...Subg. Ravnia (5 species) 

1. Corollas salverform, white to pale green or sometimes flushed with pink.

     3. Corolla lobes 4; stigmas linear, positioned below the anthers; Antilles and southern Mexico to northwestern South America... Subg. Tetrandrae (5 species)   
     3'. Corolla lobes 5-6; stigmas subcapitate to linear, positioned above or below the anthers.

          4. Stamens inserted near middle of corolla tube; stigmas linear, positioned below anthers; Ecuador and Peru...Subg. Andinae (1 species)
          4'. Stamens inserted near top of corolla tube; stigmas subcapitate to shortly linear, positioned just above anthers; Antilles and widespread in South America...Subg. Hillia (7 species)



Lower Taxa
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