Sloanea acutiflora Uittien (D. Sabatier 1234

[449] Sloanea acutiflora Uittien

(Fig. 22A)

Recueil Trav. Bot. Néerl. 22: 357 [“1925” publ. Jan. 1926] (Uittien 1926).

NOTES. — Known only from the Guiana Shield. Pennington & Wise (2017: 77) placed S. acutiflora in synonymy under S. latifolia (Rich.) K.Schum., arguing that they have the same floral morphology, and that there are intermediate states throughout the range of the species (i.e. most of Amazonia) in fruit spine development and leaf shape; the typical form of S. latifolia has long petiole and large broad leaves with rounded bases while other “forms”, typified by S. acutiflora in the Guiana Shield and S. inermis Ducke in Southern and Western Amazonia, have smaller leaves with acute or cuneate base and short petioles. Our observations contradict these statements. In French Guiana, all specimens that correspond to the Pennington and Wise concept of S. latifolia can easily be separated into two very distinct groups. In the first group, which includes the original material (see Notes under S. latifolia), trees have both buttresses and stilt roots, petioles of very variable length on the same branchlet, the longest 3-15 cm, and large leaves drying yellowish brown, of variable size but frequently 20 cm long, with rounded to obtuse, rarely cuneate base and a densely reticulate venation. Inflorescences are large, well-developed many-flowered corymbs, flower buds are slender, the base gradually attenuated on the pedicel, and covered with a dense yellow tomentum. Fruit is up to 4.5 cm long, brown, smooth, and seeds are surrounded by a white to pink aril (Fig. 22D). Trees of the second group have buttresses but no stilt roots. Petioles are shorter (usually <1 cm, rarely 1-1.5 cm). Leaves dry to a light green, and are much smaller (rarely up to 15 cm long), with an acute-attenuated base, never round or obtuse, and a much looser reticulum. Inflorescences are short, more or less cymose, bearing 1-3 (-5) flowers. Buds are subglobose to ovoid, the base abruptly reduced at the junction with the pedicel, the whitish, much less dense pilosity making them appear greyish rather than yellow. Fruit is red or pink, less than 2.5 cm long, sometimes covered with sparse, short conic spines, and the aril is orange (Fig. 22A). This last group corresponds with the type of S. acutiflora. Pennington & Wise (2017: 77) designated the lectotype of S. acutiflora as “[...] BW 6298 (lectotype, U, chosen here; isolectotypes, K, L)”. At U there are three sheets of C.J. Zaandam-Boschwezen Suriname 6298; these sheets (barcodes U0001682, U0001683, U0001684) are all kept together, and according to Art. 8.3 of the ICN (Turland et al. 2018), they are here treated as a single specimen with multiple preparations. Isolectotypes are at K(not seen), L(L0013589), RB(RB00538334) and US (00098537).

Although the distributions of these two groups overlap throughout much of French Guiana (west, center and south), no intermediate states have yet been found between the character syndromes defining these two groups. It is also interesting to note that, except in the extreme south of the territory (Tumuc-Humac Mounts), the “typical” S. latifolia form has never been found within 50 km of the border with Suriname. In view of the above, the reinstatement of S. acutiflora appears necessary.

VERNACULAR NAMES. — Pa: waaduk-seine.

HERBARIUM DATA (FG). — 27 collections at CAY. Sel. exs.: D. Sabatier 1234.

INVENTORY DATA (FG). — 39 trees in 31 plots; Fmax <1 %; dbhinv = 65 cm.