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Published In: Hooker's Icones Plantarum 12. 1873. (31 Apr 1873) (Hooker's Icon. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library

Project Name Data (Last Modified On 10/6/2016)
Acceptance : Accepted
Note : Tribe Coussareeae
Project Data     (Last Modified On 1/5/2013)

The genus Heterophyllaea includes two species of small to medium-sized shrubs found in dry vegetation in the Andes of Bolivia and Argentina. Heterophyllaea is characterized by its shrubby xerophytic habit with the small leaves borne on short-shoots, its showy flowers borne on well developed pedicels or peduncles, its calyx and corolla each with 5 lobes, and its capsular subglobose fruits with loculicidal dehiscence and a number of circular, flattened, winged seeds. Heterophyllaea is unusual in Rubiaceae in the pustulose to pellucid, rather large glands found on the leaves and sometimes the stipules, calyx, and corolla, and its leaves with the margins frequently create to serrate. Bacigalupo's illustration of Heterophyllaea pustulata (Bacigalupo, 1993, p. 379, fig. 154) presents a quite complete analysis of the genus. As with many dry-land shrubs, there is notable variation in leaf size and shape among plant and sometimes on different stems of the same plant, and also some similar variation in calyx and corolla size, which presumably correlates with variation in available moisture.

Heterophyllaea is similar to Hindsia, and has been confused with it by several authors; Hindsia differs in its septicidal capsule dehiscence and generally sessile or only shortly pedicellate flowers, and is found in southeastern Brazil. Heterophyllaea is also similar to Bouvardia of Mexico and Central America; Bouvardia differs from Heterophyllaea in its 4-merous flowers. Manettia is also similar, but can be separated by its twining climbing habit, its 4-merous flowers, and its habitat generally in humid evergreen vegetation. Heterophyllaea has also sometimes been confused with Randia, which also grows in arid vegetation, but Randia has the corolla lobes convolute in buds, fleshy indehiscent fruits, and short-shoots that are frequently developed into spines.

Author: C.M. Taylor.
The content of this web page was last revised on 5 January 2013.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml


Distribution: Dry vegetation in the Andes at ca. 1200-3300 m, southern Peru through Bolivia to central Argentina (Tucuman).


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Small to medium-sized shrubs, unarmed, terrestrial, with raphides in tissues, generally with many or all of the leaves borne on short-shoots (brachyblasts), generally with rather large pustlose to pellucid glands in the tissues. Leaves opposite, often small, with tertiary and quaternary venation not lineolate, without domatia, sometimes (Heterophyllaea pustulata) with margins crenate or serrate; stipules interpetiolar or shortly fused around stem or to petiole bases, generally persistent with leaves, triangular, generally erect and flat or perhaps imbricated in bud. Inflorescences terminal and in uppermost leaf axils, in few-flowered lax cymes or with flowers solitary, pedunculate, bracteate. Flowers distiylous, rather large and showy, pedunculate or pedicellate, sweetly fragrant, perhaps sometimes nocturnal; hypanthium ellipsoid; calyx limb deeply 5-lobed, without calycophylls; corolla salverform, white to dark blue, purple, or violet, pubescent internally in tube with pubescence pattern apparently differing between flower morphs, externally generally glabrous, lobes 5, triangular, valvate in bud; stamens 5, inserted in upper part of corolla tube, filaments short, anthers narrowly ellipsoid, dorsifixed, included in long-styled flowers and partly to fully exserted in short-styled flowers; ovary 2-locular, ovules numerous in each locule, imbricated on axile placentas; stigmas 2-lobed, exserted in long-styled flowers and included in short-styled flowers. Fruit capsular, subglobose to weakly didymous, stiffly chartaceous to woody, loculicidally dehiscent from apex, valves remaining fused at base for a time, spreading up to ca. 45°, with the suborbicular septum and attached placentas generally separating and falling from capsule, with calyx limb persistent; seeds flattened, medium-sized, suborbicular to ellipsoid, marginally winged, entire to finely densely erose.


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Key to Species of Heterophyllaea; by C.M. Taylor

1. Leaves narrowly elliptic-oblong to narrowly elliptic, 0.4-3.5 x 0.1-0.9 cm, obtuse to rounded at apex, with margins entire to sometimes undulate; calyx lobes 3-6 mm long; corolla externally dark blue, purple, violet, or occasionally white, internally pale blue, pale purple, or white, with tube 18-50 mm long, lobes 4-6 mm long; seeds 3-3.5 mm diam.; southern Peru through Bolivia....H. lycioides

1'. Leaves lanceolate to narrowly lanceolate, 1.5-6(10) x 0.3-1.5(2) cm, acute at apex, with margins usually crenate to serrate; calyx lobes 6-8 mm long; corolla white or pink-purple externally and white internally, with tube 40-70 mm long and lobes 10-12 mm long; seeds ca. 2.5 mm diam.; southern Bolivia and Argentina....H. pustulata

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