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Published In: Histoire Naturelle des Quinquinas 94, t. 27b. 1849. (Hist. Nat. Quinquinas) Name publication detail
 

Project Name Data (Last Modified On 1/2/2013)
Acceptance : Accepted
Project Data     (Last Modified On 5/27/2014)
Notes:

The genus Pimentelia is classified in the Tribe Cinchoneae, and includes one species of small to medium-sized trees found in wet forests in Peru and Bolivia. Pimentelia has been little-known until its recent good documentation by Vásquez and collaborators in central Peru. It can be recognized by the combination of its tough-textured leaves with well developed pubescent domatia on the lower surface, its well developed, ligulate, generally obtuse stipules that are held erect and pressed together in bud, its axillary inflorescences with numerous small white flowers, and its woody, rather small, cylindrical capsules with numerous narrow winged seeds. The flowers have not been collected often, and in fact were not known until recently. These are white, densely pubescent, and now documented to be distylous; no odor has been described, and it is unknown if they are nocturnal. The capsules are rather distinctive in their dehiscence mode: they are septicidal and open from the top, with the valves curving back but remaining fused at the base and persistent on the infructescence. These capsules are sometimes a little asymmetric in dehiscence, splitting below the apex with one valve retaining the entire calyx limb and the other smaller; however some plants have symmetrical dehiscence and others have variation in this form within an individual inflorescence.

Pimentelia is similar to Stilpnophyllum, which is found in the Andes of southern Ecuador and Peru and is also not well known. Andersson (1994, 1995) recognized these as separate genera, and distinguished them only by leaf characters. These both have tough-textured leaves, resinous stem apices, and similar stipules, inflorescences, flowers, and fruits, and are both found in similar habitats. Their separation is outlined below, and may deserve re-evaluation.Pimentalia is also similar, especially in fruit, to Macrocnemum; however Macrocnemum differs in its chartaceous to papery leaves as well as several fruit characters, including the stiffly chartaceous texture of the capsules and their longitudinal dehiscence, with the valves remaining fused throughout and opening along sides at the septa. Pimentelia is also similar in general aspect and sometimes habitat to Retiniphyllum, which has stipules that are fused around the stem into a sheath, generally terminal inflorescences, and 5-locular ovaries that develop into drupaceous fruits.

Author: C.M. Taylor.
The content of this web page was last revised on 10 May 2014.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml

 

Distribution: Neotropics: wet premontane to montane forests, ca. 600-2300 m, central Peru to northern Bolivia.
References:

 

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Description of Pimentelia Wedd., by C.M. Taylor (MO), 2014

     Small to medium-sized trees, unarmed, terrestrial, without raphides in tissues, markedly resinous at stem apices. Leaves opposite, with tertiary and quaternary venation not lineolate, on lower surface with well developed pubescence domatia at junctions of secondary veins with costa; stipules quickly deciduous, interpetiolar, triangular, generally held erect and flatly pressed together in bud. Inflorescences axillary (i.e., present in both axils of the node), borne with leaves near to well below stem apex, thyrsiform to paniculiform, multiflowered, pedunculate, bracteate. Flowers sessile or subsessile in groups of 3-5, rather small, distylous; hypanthium ellipsoid; calyx limb shallowly 5-lobed, without calycophylls; corolla funnelform, white, densely villous internally in tube and throat and villosulous on margins of lobes, lobes 5, triangular, valvate in bud; stamens 5, inserted in corolla tube, anthers narrowly ellipsoid, dorsifixed near base, included in long-styled flowers and exserted in short-styled flowers; ovary 2-locular, ovules numerous in each locule, imbricated and ascending on axile placentas; stigmas 2-lobed, quite succulent, exserted in long-styled flowers and included in short-styled flowers. Fruit capsular, cylindrical, woody, septicidally dehiscent from apex, valves spreading but remaining fused and persistent at base, sometimes a little asymmetric with capsule apex and entire calyx limb retained on one valve; seeds flattened, small, fusiform, marginally winged, acuminate at one end and 2-lobed at the other.

 

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Key to Pimentelia and Stilpnophyllum

1. Leaves with ca. 8-12 pairs of secondary veins, without intersecondary veins, below (i.e., abaxially) with well developed pilose to villose or villosulous domatia regularly developed at the junctions of secondary veins with costa.....Pimentelia

1'. Leaves with ca. 12-35 pairs of secondary and intersecondary veins, these two types similar and often difficult to distinguish, below without domatia, with foveolate and villosulous domatia present but irregularly developed, or sometimes with regularly well developed pilose to villose or villosulous domatia (S. grandifolium)....Stilpnophyllum

 
 
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