Guatteria acrantha Erkens & Maas

Maas, P. J. M., Westra, L. Y. T., Guerrero, S. Arias, Lobão, A. Q., Scharf, U., Zamora, N. A. & Erkens, R. H. J., 2015, Confronting a morphological nightmare: revision of the Neotropical genus Guatteria (Annonaceae), Blumea 60 (1), pp. 1-219 : 24

2. Guatteria acrantha Erkens & Maas — Map 2

Guatteria acrantha Erkens & Maas in Erkens et al. (2006) 202, t. 1, f. 2, 3. — Type: Rivera 355 (holo STRI; iso MO, PMA, U), Panama, Los Santos, Distr. Tonosí, Cerro Los Piraguales, El Cortezo, 900 m, 20 April 1994.

Tree or shrub 4–20 m tall; young twigs sparsely covered with appressed hairs, soon glabrous. Leaves: petiole 1–3 mm long, c. 1 mm diam; lamina narrowly obovate to narrowly el- liptic, 5–8 by 2–3.5 cm (leaf index 2.2–2.8), chartaceous, not verruculose, dull, dark brown above, brown to brownish green below, glabrous above, rather densely covered with appressed hairs below, base attenuate, apex rounded or sometimes very shortly and bluntly acuminate (acumen <2 mm long), primary vein flat to slightly impressed above, secondary veins distinct, 6– 9 on either side of primary vein, flat to slightly raised above, smallest distance between loops and margin 1–2 mm, tertiary veins flat to slightly raised above, reticulate. Flowers solitary, terminal or also in axils of leaves; flowering and fruiting pedicels 5–12 mm long, c. 1 mm diam, densely covered with appressed, brown hairs, articulated at 0.2–0.3 from the base, bracts of terminal flowers 1–2, foliaceous (?), soon falling, not seen, bracts of axillary flowers c. 5, soon falling, not seen; flower buds broadly ovoid; sepals free, broadly ovate-triangular, 3–5 by 3–4 mm, appressed to reflexed, outer side densely covered with appressed, brown hairs; petals greenish in vivo, broadly ovate-triangular, 7–9 by 5–7 mm, outer side densely covered with appressed, brown hairs; stamens 1–1.5 mm long, connective shield papillate. Monocarps c. 10, green in vivo, black in sicco, narrowly ellipsoid, 7–10 by 3–4 mm, subglabrous, apex apiculate (apiculum c. 1 mm long), wall c. 0.1 mm thick, stipes 1–2 by 1 mm. Seed narrowly ellipsoid, c. 8 by 3 mm, brown, pit- ted to rugose and more or less distinctly longitudinally grooved, raphe distinct, flat to slightly raised.

Distribution — Panama (Chiriquí, Los Santos, Veraguas).

Habitat & Ecology — In cloud forest. At elevations of 900– 1500 m. Flowering: February to April, July; fruiting: April.

Note — Guatteria acrantha is unique by its solitary terminal, minute flowers and by its very tiny, mostly roundish tipped leaves. Superficially, it looks similar to G. rotundata by the shape of its leaves, but it is quite distinct by having terminal flowers.