Eschweilera juruensis R.Knuth

  • Family

    Lecythidaceae (Magnoliophyta)

  • Scientific Name

    Eschweilera juruensis R.Knuth

  • Primary Citation

    Pflanzenr. (Engler) IV, 219a: 111. 1939

  • Type Specimens

    Specimen 1: Isotype -- B. A. Krukoff 5755

  • Description

    Author: Scott A. Mori

    Type: Brazil. Acre: near mouth of Rio Macauhan (trib. Rio Yaco), 9°20'S, 69°W, 3 Sep 1933 (fl), Krukoff 5755 (holotype, B, not found; lectotype, NY, designated by Mori & Prance, 1990; isolectotypes, BM, K, M, MO, NY, RB-2 sheets, U, US).

    Description: Trees, to 14-35 m tall. Trunk buttressed. Stems 5 mm diam., the newly flushed black, the older brown when dry. Petioles hemispherical in cross-section, canaliculate, 10-24 mm long, glabrous, black; blades elliptic, broadly elliptic, or narrowly to broadly oblong, 9-29 x 5-10 cm, coriaceous, glabrous, punctate and minutely papillate abaxially, discolorous, the adaxial darker and smoother than abaxial surface, the base obtuse, the margins entire, the apex short acuminate; venation eucamptodromous toward base, brochidodromous for rest of length, the midrib plane adaxially, salient abaxially, glabrous, the secondary veins in 13-25 pairs, decurrent, plane adaxially, plane to prominulous abaxially, 5-12 mm apart in middle of blade, the intersecondary veins well-developed, one between adjacent pair of secondaries, the tertiary and higher order venation reticulate, the areoles very small. Inflorescences usually terminal, sometimes axillary, unbranched or once-branched, racemose, the rachis distinctly angled, 2.5-15 cm long, usually drying black, often with distinct, lighter colored scars left by caducous bracts; pedicels very short below articulation, the bracts and braceoles caducous. Flowers 4-5 cm diam.; calyx-lobes 6, the lobes widely to very widely ovate, 9-13 x 7-11 mm, oriented obliquely to nearly horizontally at anthesis, convex abaxially, flat to slightly concave adaxially, black when dried, the bases imbricate; petals 6, widely obovate, 26-43 x 21-30 mm, white, cream-colored, or yellow; androecium zygomorphic, the hood double-coiled, the second coil very short, white with yellow at margin of opening into flower; staminal ring with ca. 500 stamens, a staminal rim lip present, the filaments clavate, slightly curved, 3-3.5-5 mm long, the anthers ca. 1 mm long; hypanthium glabrous, drying black, tapering to articulation; ovary 2-locular, each locule with 6-8 basally attached ovules, the style 3.5 3-5 mm long, the summit plateau-like, the style obconical, not well-differentiated from summit of ovary. Fruits depressed globose, the calyx-lobes reflexed in fruit, the infracalycine zone truncate to pedicel, the supracalycine zone erect to slightly flaring outward, the pericarp 2-4 mm thick, the exocarp rough, light brown when fruit dry, the operculum nearly flat to slightly convex. Seeds globose or triangular in cross section, ca. 3.5 x 3.5-4 cm, the seed coat thin, ca. 1 mm thick, the venation plane, dendritic. Aril lateral.

    Common names: Brazil. mata-matá castanha (Prance et al. 23933, locally called this because of resemblance of leaves to those of Bertholletia excelsa), mata-matá roxo (Daly et al. 10998). Peru. machimango (Rimachi Y. 3245, a name applied to various species of Eschweilera in Peru).

    Distribution: This species is found in western Amazonia in Ecuador, Peru, Brazil, and Bolivia.

    Ecology: Generally a canopy tree of terra firme forests but two collections (Prance et al. 23933 and Rimachi Y. 3245) indicate that it is a common tree in periodically flooded varzea forest where it is said by both collectors to be frequent. See "Taxonomic notes" below.

    Phenology: Flowers have been collected in Aug, Sep, Oct, and Nov and fruits with mature or nearly mature seeds have been gathered in Sep and Feb.

    Pollination: No observations recorded but this species is most likely pollinated by bees as are all other species of this genus for which pollination observations are available (Mori & Boeke, 1987).

    Dispersal: No observations recorded. This species has a lateral aril that may be eaten by animals which in turn disperse the seeds.

    Predation: No observations recorded.

    Field characters: This species is characterized by medium-sized to large leaves with the midrib plane, especially toward the base adaxially; discolorous leaf blades with the abaxial surface lighter and smoother than the adaxial surface; inflorescences usually terminal, unbranched, the rachises very black with ligher colored bract scars; hypanthiuim tapered to articulation, glabrous, black; imbricate calyx-lobes; androecial hood double-coiled but with the second coil very short; and depressed globose fruits with the infracalycine zone truncate to the pedicel, the calyx-lobes reflexed, and the supracalycine zone erect or slightly flared outward.

    Taxonomic notes: In nearly all features, Eschweilera juruensis is a smaller-leaved version of E. gigantea. Both species have a smooth adaxial and rougher abaxial leaf blade surfaces; glabrous, black, and angular inflorescence rachises; and the hypanthia of the two species are glabrous and black in herbarium specimens. In addition to the leaf size difference, the hypanthia of E. juruensis is more tapered than that of E. gigantea. Because many Amazonian species found in periodically inundated forests have their nearest relatives in terra firme forest (Ducke, 1948), the populations represented by herbarium collections of E. juruensis gathered from várzea forest (see "Distribution" above) need to be carefully studied to determine if they represent an ecologicallyi variable species or if the riverine populations represent a species different from the Terra firme populations.

    Conservation: IUCN Red List: Not on list (March 2014).

    Uses: None recorded.

    Etymology: The species epithet alludes to the Juruá River from where specimens cited in the protologue were collected.

    Source: Based on Mori & Prance (1990).

    Acknowledgements: I am grateful to X. Cornejo and A. Pérez for allowing the use of their images.

  • Floras and Monographs

    Eschweilera juruensis 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.