Terminalia guyanensis Eichler in Mart.

Engel, Julien & Sabatier, Daniel, 2020, Terminalia carinata Sabatier & J. Engel, sp. nov. (Combretaceae), a new large tree species from the Guiana shield revealed by re-examination of material previously identified as T. guyanensis Eichler, Adansonia (3) 42 (16), pp. 261-271 : 267-270

Terminalia guyanensis Eichler in Mart.

( Figs 3 , 4 , 5 , 6 )

Flora Brasiliensis 14 (2): 88 (1867). — Myrobalanus eichleriana Kuntze, Revisio Generum Plantarum 1: 237 (1891), nom. nov. pro Terminalia guyanensis Eichler , non Myrobalanus guianensis Kuntze (1891) , nec. Terminalia eichleriana Alwan & Stace (1989) . — Typus: French Guiana. 1817-1822, Poiteau s.n. (holo-, B, destroyed, photograph at FI; iso-, K [ K000640657 ], P [ P01901252 , P01901253 , P01901254 ]!, U [ U0001197 ], W [ W-Rchb. 1889-0125487 ]); No collector (probable iso-, A / GH [ GH00068628 ]).

DISTRIBUTION. — The specimens consulted were collected in Venezuela and French Guiana. It is very likely that T. guyanensis also occurs in the region between these two countries, which would include Guyana, Suriname and adjacent areas in Brazil.

HABITAT. — According to herbarium sheets and inventory data from the GUYADIV and GUYAFOR networks ( Engel 2015), T. guyanensis is encountered in terra-firme forest between 100 to 810 m elevation. Its privileged habitat seems to be cloud forest and very rainy forest receiving more than 3500 mm of precipitation per year. PHENOLOGY. — Flowers were collected in November during leafless stage, fruits in March and May.

CONSERVATION STATUS. — Based on the herbarium sheets consulted, T. guyanensis is known from five localities in French Guiana and two localities in Venezuela. Outside one site in French Guiana (Mont Itoupé) where T. guyanensis is relatively common, the authors rarely encountered this species during the inventory work carried out as part of the GUYAFOR and GUYADIV networks. More precisely, out of the almost 180 000 trees inventoried in these two networks, only 12 were identified as T. guyanensis . The calculated AOO is 32 km ², the calculated EOO is 138589 km ² which is very high as this species has been collected in Venezuela and French Guiana and is thus very likely to also occur in Guyana and Suriname. In countries where T. guyanensis has been collected, as well as in countries where this species is probably present, the forest massif is generally (still) preserved. Terminalia guyanensis is thus classified as Least Concern (LC) following the IUCN Red List criteria ( IUCN 2012). However, even if the forest massif is not directly threatened by human activities, T. guyanensis is one of the many rare Amazonian tree species with low densities and unknown ecological requirements and whose regeneration could potentially be affected by climate change ( ter Steege et al. 2013; Esquivel-Muelbert et al. 2018).

AFFINITIES. — Like 14 other neotropical Terminalia , T. guyanensis has 2-winged fruits, each wing> 1 cm long. But only T. argentea Mart. & Zucc. , T. januarensis DC. and T. phaeocarpa Eichler have quite similar fruit body, bulging on both faces, although often with a slight ridge or slightly wavy while the surface of T. guyanensis fruit body is rounded and smooth. Vegetatively, these three species can be distinguished from T. guyanensis by their pubescent or subglabrous leaves (but at least they are pubescent on main veins abaxially) while T. guyanensis leaves are glabrous. If we consider more specifically the 15 species of Terminalia found in French Guiana (including T. carinata Sabatier & J.Engel , sp. nov.), five are immediately distinguishable by the size of their leaves, which are clearly larger ( T. aubletii Gere & Boatwr. , T. macrophylla (Eichl.) Gere & Boatwr. , T. megalophylla (Van Heurck & Müll.) Gere & Boatwr , and T. nitidissima Rich. ), or smaller ( T. parvifolia (Ducke) Gere & Boatwr. ) than those of T. guyanensis . And none of the other species has glabrous leaves with such brochidodromous veins with one or two sets of loops outside of the main brochidodromous loop.

OTHER MATERIAL STUDIED. — French Guiana. Mont Itoupé , 430 m, 3°1’21”N, 53°6’29”W, fl., 17.XI.2014, Sabatier et al. 6018 ( CAY [- CAY182882 !], P [ P01155923 !]) ; Mont Itoupé , inv. code ITO1- K 4, 600 m, 3°1’20”N, 53°5’29”W, fr., 12.III.2010, Sabatier & Molino 5682 ( CAY [ CAY103783 !]) ; Mont Itoupé , 433 m, 3°2’22”N, 53°6’19”W, fr., 13.III.2017, Sabatier 6331 ( CAY [ CAY182884 !], P [ P01155924 !]) ; Mont Itoupé , inv. code ITOW 8-5, 328 m, 3°3’18”N, 53°6’34”W, st., 12.XI.2014, Sabatier et al. 6051 ( CAY [ CAY182883 !]) ; Mont Itoupé , 3°1’18”N, 53°7’10”W, 200 m, st., 20.III.2010, Molino & Sabatier 2794 ( CAY [ CAY104624 !], MPU) ; Réserve Trésor , inv. code T 10380, 235 m, 4°34’12”N, 52°17’24”W, st., 1.IX.2008, Engel et al. 16 ( CAY [ CAY182881 !]) ; Massif Lucifer, plateau Tabulaire , 530 m, 4°47’11”N, 53°55’23”W, st., 15.XI.1999, Dutreve 355 ( CAY [ CAY046077 !]) ; Station des Nouragues, Bassin de l’Arataye , inv. code NOU3-146 , 4°3’N, 52°42’W, st., 7.VII.1989, Sabatier & Prévost 2627 ( CAY [ CAY010136 !], LTR) ; Montagne de Kaw , st., 16.IX.1969, Petrov 203 ( CAY [ CAY170282 !], P [ P04717175 !]) ; ibid., 17.IX.1969, Petrov 208 ( CAY [ CAY182888 !], P [ P04717176 !]) . Venezuela. Territorio federal, delta Amacuro: bosque pluvial, Este de Río Grande. Este-Noreste de El Palmar, cerca de los limites del Estado Bolívar, fr., 23. V.1964, Marcano Berti 187 ( A / GH, BM, F [ V0397201 F], MG, US [ US00766632 ], VEN) ; East of Cerro El Picacho , near Las Nieves & Las Chicharras, 45 km North of Tumeremo, 600-650 m, st., 5-8.II.1961, Steyermark 89070 ( A / GH, P [ P04717179 !], S, VEN) .

DESCRIPTION

Deciduous canopy tree up to 60 m tall, with thick, rounded buttresses to 1–2 m high. Diameter up to 105 cm. Bark brownyellow, densely scaly, inner bark pale yellow.Twigs pubescent, becoming glabrous; terminal buds densely pubescent. Leaves alternate, spirally arranged, usually clustered at branchlet tips; blades chartaceous, elliptic-oblong to elliptic, 5-13 × 2-5 cm; apex acuminate; base cuneate or attenuate-cuneate; margin entire; both surfaces glabrous, except rarely a tuft of hairs in axils of secondary veins abaxially; lateral veins 7-10, uniformly pinnate, intersecondary veins often present, brochidodromous, with one or two sets of loops outside of the main brochidodromous loop, slightly raised on both surfaces, lower venation randomly reticulate, visible on both surfaces; petioles 0.8-2 cm, slightly pubescent or usually glabrous, often with a pair of small glands toward apex.

Inflorescences axillary, clustered in c. 6-13 spikes at leafless branchlet-ends, 1.5-3 cm long, covered by lanate trichomes, c. 25-40-flowered; peduncle 0.4-1.1 cm long; bracts inconspicuous and caducous. Flowers bisexual, pale yellowish, actinomorphic, 1.6-3 × 1.5-2.3 mm; lower hypanthium extended into a short “neck” surrounding the ovary, 0.8-1.5 mm long, densely pubescent, upper hypanthium cupuliform to campanulate, 0.8-1.6 mm long, pubescent on the external surface, lanate with much longer trichomes on the inner surface; calyx lobes 5, 0.6-1 mm long, pubescent on the external surface, lanate with much longer trichomes on the inner surface; petals 0; stamens 10, white, glabrous, 2.1-2.8 mm, anthers versatile, c. 0.3 mm long; intrastaminal disk c. 1.2 mm width, slightly lanate; ovary inferior, unilocular, style exserted, 2.4-3.7 mm long, slightly lanate over about a third of its lower part. Infrutescence with 1-2 fruits, peduncle and rachis slightly pubescent or usually glabrous. Fruits 2-winged, dry, glabrous and shiny, 4.9-6.3 × 1.8-2.4 cm, apex shortly acuminate, flat or slightly emarginate, base obtuse; wings stiff, green, (sub) equal, 2-2.8 cm long, rounded to narrowly rounded; body c. 0.5-0.7 cm wide, c. 4 mm high, bulging on both faces.

NOTE

We have previously discussed the confusion between T. guyanensis and T. carinata Sabatier & J.Engel , sp. nov. Sterile specimens of T. guyanensis have sometimes also been confused with T. dichotoma G. Mey. Thus , three specimens studied by the authors (Sabatier & Prévost 2627, Petrov 203 and Petrov 208) and cited in the present study are recorded as T. dichotoma in Stace (2010) . These two species can be distinguished from each other by their venation pattern: T. guyanensis veins are more brochidodromous with one or two sets of loops (absent in T. dichotoma ) outside of the main brochidodromous loop.

Figures

FIG. 3. — Leaf abaxial surface in SEM:A-D, Terminalia carinata Sabatier & J.Engel, sp.nov.; note the hidden stomata; E, F, Terminalia guyanensis Eichler;A, B, Sabatier et al. 4891; D, E, De Granville et al. 10958; E, F, Sabatier et al. 6018. Scale bars: A, C, E, 200 µm; B, D, F, 100 µm.

FIG. 4. — Distribution of Terminalia guyanensis Eichler and Terminalia carinata Sabatier & J.Engel, sp. nov.: (·) T. guyanensis and (▲) T. carinata Sabatier & J.Engel, sp. nov., herbarium specimens; () T. guyanensis and () T. carinata Sabatier & J.Engel, sp. nov., observations (no voucher) from the GUYADIV and GUYAFOR networks (Engel 2015).

FIG. 5. — Terminalia guyanensis Eichler: A, fruiting branch; B, transverse section of fruit; C, inflorescences; D, longitudinal section (left) and lateral view (right) of flower; A, B, Sabatier 6331 (CAY); C, D, Sabatier & al. 6018 (P). Drawn by Laurence Ramon. Scale bars: A, B, 2 cm; C, 1 cm; D, 1 mm.

FIG. 6. — Terminalia guyanensis Eichler: A, fruiting branch; B, inflorescences; C, trunk; D, bark with a machete slash; A, Sabatier & Molino 5682 (CAY); B-D, Sabatier et al. 6018 (P). A-D, Photographs by Daniel Sabatier.