Vantanea maculicarpa Sabatier & Engel, 2018

Engel, Julien & Sabatier, Daniel, 2018, Vantanea maculicarpa (Humiriaceae): a new tree species from French Guiana, Phytotaxa 338 (1), pp. 130-134 : 131-133

Vantanea maculicarpa Sabatier & Engel , sp. nov. ( Figs. 1 and 2 )

Type :— FRENCH GUIANA. RN2 Cayenne—Régina, niveau Petites Montagnes Tortue, 4°18’N, 52°15’W, 1 November 2009, D. Sabatier 5574 (Holotype CAY! (barcode CAY111685 ); Isotype P! (barcode P01156374 )) .

Diagnosis: — Vantanea maculicarpa is distinguished from all other species of Vantanea by its fruits that are covered by white lenticels, a character so far unknown in this genus as all other species of Vantanea have smooth, slightly pubescent or rarely tuberculous fruit surface ( V. tuberculate Ducke (1938: 31 , pl.5)). Fruits shape is globose, another distinctive feature of V. maculicarpa , as fruits are mostly ovoid or ellipsoid in this genus. Regarding flowers, V. maculicarpa has a pubescent disk, a feature shared by two other species only, V. parviflora and V. ovicarpa respectively. The new species closely resembles V. parviflora : they share leaves greenish-brown above, with secondary and smaller veins visible on both sides, and petioles thickened at base. V. maculicarpa is distinguished by shorter petiole and obovate blades while V. parviflora has more elliptical blades. Regarding flowers, V. maculicarpa differs from V. parviflora in having more stamens (150–230 against 80–120). Filaments length is also more variable (within a same flower) in V. maculicarpa , while it is more uniform in V. parviflora . The length ratio between the longest and the smallest filament of a same flower is also more variable between flowers in V. maculicarpa . To get an approximate picture, this ratio ranges from about 2 to 5 in V. maculicarpa , while it is ranging around 1.6 and quite homogeneous among flowers in V. parviflora . V. maculicarpa differs from V. ovicarpa in having globose, strongly rugose and smaller endocarp with 5 valves while the latter has large, ovoid, smooth endocarp with 6–7 valves.

Description: — Tree, up to 40 m tall, 80 cm dbh; bole irregular, buttressed; bark becoming fibrous with age; branchlet terete, glabrous. Leaves simple, alternate, rigid coriaceous, glabrous, with several small glands scattered on lower surface, ca. 4–11 × 3–6 cm, margins entire, blades obovate, cuneate or attenuate at base, rounded and emarginated at apex, sometimes shortly acuminate, midvein prominently raised on abaxial surface, slightly raised on adaxial surface, secondary veins 8–10, arcuate and united near the margin, smaller veins reticulate; petiole sulcate, usually thickened at base, 4–6 mm long. Inflorescence paniculate-cymose, ca. 9 cm long, axillary or terminal, axis pubescent, pedicels ca. 0.5 mm long, pubescent; bracts deciduous. Flower buds 0.8–1 cm long; calyx broadly cupulate, ca. 3 mm long, 2 mm diameter, entire or slightly 5-lobed, minutely pubescent; petals valvate in bud, white, linear, rather thick, 5–8.5 × 1–1.5 mm, pubescent outside, hairs abundant, glabrous inside; stamens 150–230, united at base, filaments glabrous, white, 1–6 mm long with high variability within and among flowers (within-flower ratio between the length of the longest and the length of the smallest filament ranging from 2 to 5); anthers lanceolate, ca. 0.7 mm long, affixed near the base, orangish-yellow; thecae 2, bilocular, ca. 0.3 mm long; the connective long and acute (about half the length of the anther); disk thick, cupular, densely pubescent abaxially and in its adaxial upper-third; ovary 1.6 × 0.6 mm, globose-ovoid, densely crisp-pubescent, 5-locular; style ca. 3.6 mm long, sparsely pilose at base; stigma small, rounded. Fruit a globose drupe, ca. 2.5 cm in diameter, dark with numerous whitish lenticels; mesocarp ca. 3 mm thick, firm; fruit stone (pyrene) woody, strongly rugose, with 5 linear, ca. 5 mm wide, valves alternating with broad ribs; one (two) seed ca. 5 × 2.5 mm.

Phenology: —Flowers of Vantanea maculicarpa have been observed from the end of the rainy season in June to the dry season in November, immature fruits in October and mature fruits during the rainy season in April–May.

Distribution and Ecology:—The new species occurs in French Guiana terra-firme forest.

Etymology: —The epithet refers to the surface of the fruits covered by numerous white lenticels.

Conservation status: —The new species is known from 9 widely spaced localities of French Guiana, and these localities are not threatened by human activities. The Area of Occupancy (AOO) calculated is 28 000 km². Vantanea maculicarpa is thus classified as Least Concern (LC) following the IUCN Red List criteria ( IUCN 2012).

Additional specimens examined (paratypes): —FRENCH GUIANA. Petite Montagne Tortue , 4°13’N, 52°13’W, 10 June 2005 (fl.), D. Sabatier & M. F. Prévost 4911 ( CAY! (barcode CAY073328 ), P (barcode P04782086 ), NY) ; piste de Nancibo , 4°41’N, 52°30’W, 12 April 1985 (fr.), D. Sabatier 1071 ( CAY! (barcode CAY080681 , CAY080680 )) ; DZ Saut Dalles , 3°16’N, 53°49’W, 05 May 1990 (fr.), D. Loubry 706 ( CAY! (barcode CAY166269 ), NY, US, CBS, MPU (barcode MPU216145 )) ; Massif des Emérillons , crête à 4.5 km au Sud du Piton Baron, 3°17’N, 53°4’W, 27 October 2007 (imm. fr.), D. Sabatier & J. F. Molino 5342 ( CAY! (barcode CAY104064 , CAY104065 )) ; Crique Wapou , 4°25’N, 52°9’W, May 2005 (fr.), D. Sabatier 4898 ( CAY! (barcode CAY171556 ), P! (barcode P01156368 ) ; Nancibo , 4°40’N, 52°29’W, 15 November 1985 (st.), D. Sabatier 1130 ( CAY! (barcode CAY166268 )) ; Nancibo , 4°40’N, 52°29’W, 27 December 1985 (st.), D. Sabatier 1172 ( CAY! (barcode CAY166267 )) ; St-Georges-Régina, entre pk 25,4 et pk 27, 4°1’N, 51°58’W, 4 November 1998 (st.), P. Grenand 3062 ( CAY! (barcode CAY000286 ), MPU, MO, G) .

Figures

FIGURE 1. Vantanea maculicarpa (photographs A–C by Daniel Sabatier and D–E by Julien Engel).A. Flowering branch. B. Flower buds and flowers. C. Medial section of flower (note the pubescent intrastaminal disk). D. Two fruits (right), transverse section with one seed (below left) and upper view of endocarp (above left). E. Fruit surface showing white lenticels. (A. Sabatier & Prévost 4911. B–C. Sabatier 5574. D–E. Sabatier 4898).

FIGURE 2. Vantanea maculicarpa. A. Flowering branch. B. Detail of stamens. C. Mature leaf. D. Medial section of flower. E. Flower at anthesis. F. Flower bud. G. Mature (left) and immature (right) fruit. H. Endocarp. (A–C. Sabatier 5574. D–F. Sabatier & Prévost 4911. G. Sabatier 4898, Sabatier 5342. H. Sabatier 4898). (Drawn by Laurence Ramon)