Eschweilera amazonica R.Knuth
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Family
Lecythidaceae (Magnoliophyta)
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Scientific Name
Eschweilera amazonica R.Knuth
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Primary Citation
Pflanzenr. (Engler) IV, 219a: 109. 1939
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Description
Author: Scott A. Mori, G. T. Prance & Nathan P. Smith
Type: Type. Brazil. Amazonas: Lower Rio Negro, Uipiranga, Dec 1923 (fl), J. G. Kuhlmann 1007 (holotype, B, not extant; lectotype, RB.21510; isolectotypes, IAN, photo IAN at NY, INPA, RB-4 sheets, RB-carpoteca 844, photo RB-carpoteca 844 at NY).
Description: Small to medium-sized trees, to 20 m tall, unbuttressed. Bark at least sometimes with vertically oriented cracks, flaking in irregular plates (i.e., scalloped), the outer bark thin, 1-2 mm thick, the inner bark thicker, 15-20 mm thick, reddish. Leaves present at anthesis; petioles 5-10 mm long, terete, glabrous; blades elliptic, 5-15 x 2-6 cm, somewhat coriaceous, glabrous, the adaxial surface smooth and somewhat shiny, the base acute to obtuse, the margins entire, the apex acuminate; midrib adaxially prominulous, abaxially prominent, the secondary venation in 10-20 pairs, adaxially plane, abaxially prominulous, the tertiary and higher order venation adaxially scarcely visible, abaxially very finely reticulate, the areoles very small. Inflorescences axillary, racemose, the rachis short, 1-5 cm long, densely lenticelate; pedicels jointed, the pedicel bases persisting as short knobs 1-2 mm long, the flowers sessile above joint. Flowers 2.5-3 cm diam.; hypanthium rough, brown, truncate at base; calyx with six lobes, the lobes ovate, 4-5 x 4-5 mm, slightly erect, imbricate, more or less plane in cross section, black and smooth when dried; petals six, irregularly elliptic, yellow or white, 17-25 x 13-18 mm; hood of androecium yellow, 7-12 x 22-27, with a single coil with vestigial stamens on both the outer and inner surfaces of the coil, the vestigial stamens bright yellow; staminal ring with ca. 300 stamens in 4-6 rows on outside and more rows on ligular side, extending up ligule; staminal ring present, the filaments tapered to apex, the outermost ca. 2 mm long, tapered to apex, the anthers ca. 0.4 mm long; ovary 2-locular, each locule with numerous (ca. 28) ovules on placenta in mutliple rows, arising from lower part of horizontally spread septum, the summit with raised plateau, the style obconical and arising from the plateau. Fruits cup-shaped, campanulate, cylindric, or turbinate, 5-9.5 x 4.5-7.5 cm, the calycine ring inserted 5-20 mm below opercular opening, with protruding, calyx lobes, the pericarp to 20 mm thick, the exterior surface conspicuously reticulate, brown, rough, with longitudinally striate pattern, the interior surface smooth; operculum flat, usually slightly umbonate, 3-6 cm diam., 1-2 cm high. Seeds 7-10, oblongoid to fusiform, the venation impressed; aril basal, fleshy when fresh.
Common names: Brazil: matamata preto, matamataci (Mori & Prance, 1990)
Distribution: Endemic to Amazonian Brazil were it is distributed from the central to the eastern Amazonia.
Ecology: An understory to canopy tree found in primary or secondary terra firme forests on sandy, clay, or sandy/clay soils.
Phenology: This species flowers from Sep to Feb and fruits with mature or nearly mature seeds have been collected in Feb Jun, Jul, Sep, and Nov.
Pollination: No observations recorded, but like other species with morphologically similar flowers it is most likely pollinated by bees.
Dispersal: No observations recorded but the basal aril and the fact that the fruits open while still in the tree suggest that bats may be dispersal agents (Greenhall, 1965).
Predation: According to data provided on herbarium sheet H. L. de Vasconcelos J50, the leaves are attacked by leaf-cutting ants.
Field characters: This species has the following characters that allow it to be recognized in the field and herbarium: thin outer bark, and thicker reddish inner bark; relatively small to medium-sized leaves with a smooth, somewhat shiny adaxial leaf blade surface; short, unbranched inflorescence rachises; a rough brown hypanthium that contrasts with the smooth, black, imbricate calyx lobes on herbarium sheets; an androecial hood that has a single coil and vestigial appendages on both the outside and inside of the coil; ovules in more than on row; cup-shaped, cylindric, or turbinate fruits with the calycine-ring inserted near to the apex of the fruit and with a rough reticulately ornate pericparp; and fusiform seeds with impressed veins and a basal aril.
Taxonomic notes: Eschweilera amazonica has several features that are not characteristic of Eschweilera. In the first place, the androecial hood forms a single coil, has vestigial stamens on both the outside and inside surfaces of the coil, and does not possess the vestigial stamen nectaries characteristic of Eschweilera. A similar hood structure is found in a group of species formerly recognized as Eschweilera tetrapetala sect. Tetrapetala (Mori & Prance, 1990) plus Eschweilera nana (Huang, 2011). Section Tetrapetala and E. nana form a molecular clade outside of the true Eschweilera clade (Huang, 2010). In the second place, the seeds are fusiform and have basal arils in contrast to the plano-convex seeds with lateral arils of most species of Eschweilera, especially those species found in the Amazon. The only important floral feature that this species has with Eschweilera senus stricto is its 2-locular ovary but the ovules are inserted in multiple rows and not a single row as they are in true Eschweilera.
Conservation: Not on the IUCN list of endangered species (IUCN, 2011).
Uses: None recorded.
Etymology: The specific epithet refers to the Amazonia where it is endemic.
Source: Based on Mori & Prance (1990).
Acknowledgements: We are grateful to L. B. Viana Matta for allowing us to use her images to illustrate the characters of this species.
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Floras and Monographs
Eschweilera amazonica R.Knuth: [Article] Mori, S. A. & Prance, Ghillean T. 1990. Lecythidaceae - Part II: The zygomorphic-flowered New World genera (Couroupita, Corythophora, Bertholletia, Couratari, Eschweilera, & Lecythis). With a study of secondary xylem of Neotropical Lecythidaceae by Carl de Zeeuw. Fl. Neotrop. Monogr. 21: 1-376.
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Narratives
Inflorescence and flower morphology and anatomy of Eschweilera amazonica.
