Description

Trees: branches basitonic, in axils of cataphylls or foliage leaves, pseudo-verticillate?; twigs terete, ca. 1 mm diam.; epidermis brownish, barely visible due to indument cover; terminal bud plump, ca. 4 X 2 mm; cataphylls caducous; indument tomentose, persisting for at least two flushes, the hairs dense, up to 0.5 mm long, straight to curved, erect, brownish. Leaves: petioles slender, 0.6–1.2 cm X 0.8–1.4 mm, terete; blades thinly chartaceous, flat, broadly elliptic, (4–)8–11 X 1–6 cm; base acute to obtuse, minutely decurrent, 70–130°; apex acute, 70–110°, ultimately acuminate for up to 1.5 cm; margin plane; primary vein above slightly raised and rounded, below raised and longitudinally striate; secondary veins 3–5 pairs (slightly triplinerved, indistinguishable from tertiary veins towards apex), closer together towards the apex, eucamptodromous, above shallowly impressed, below raised, diverging at 45–60°, evenly arching, chordal angle 20–30°, lowest pair more acute than rest; tertiary veins above inconspicuous, below inconspicuous to slightly raised, random-reticulate; higher order veins above and below inconspicuous; surface above shiny yellow in young leaves, olive-green in older leaves, the primary vein slightly lighter, below dull yellow-green in young leaves, darker in older leaves, the veins slightly lighter; indument above absent, the primary vein puberulous, below minutely puberulous to glabrous, the hairs isolated, up to 0.5 mm long, straight, spreading, ascending, translucent to yellowish-brown, denser on the veins, caducous after one flush. Staminate inflorescences: basitonic to mesotonic, pendulous?, peduncles 1–6 cm long, the hypopodia 1–4 cm X 0.2–0.4 mm, branch orders 3, the second-order branches 3–5, dispersed, lowest branch up to 0.7 cm long, color and indument of all axes as on twigs; bracts caducous (not seen); bracteoles persistent or caducous, up to 1 mm long, adaxially hairy. Staminate flowers: pedicels ca. 3.2 X 0.4 mm, the diameter even throughout; receptacle flat, ca. 1 X 2.3 mm; tepals membranaceous, ovate, ca. 3 X 1.2–1.6 mm (inner whorl slightly smaller), at anthesis spreading, yellowish, translucent, adaxially tomentose; stamens of whorls I and II, the anthers, sessile, laminar obovate, ca. 1.4 X 1.6 mm, glabrous, the locelli 4, apical, in a strong arch (whorl II in two almost superposed pairs), introrse, the glands absent; whorl III capitate, ca. 1.6 X 0.6 mm, glabrous, the anthers oblong, the locelli 4, the upper pair latrorse, the lower pair extrorse, the glands flattened and fused, forming a continuous ring; whorl IV absent; all stamens yellowish-brown; pistillode absent. Pistillate flowers and fruits unknown.

Field notes

Trees up to 10 m tall and 10 cm diam. Tepals green; stamens/staminodes yellow-green.

Distribution (Figure 13)

Known only from the type locality, in moist forest, at ca. 300 m elev.  Flower buds were collected in August; the flowers were open in September, at the beginning of the dry season.

Additional specimens examined

French Guiana: Saül, Mont La Fumée, 18 Aug 1982 (stam. fl), Mori & Boom 14737 (CAY, NY.)

Discussion

Rhodostemonodaphne leptoclada can be recognized by its slender brown-tomentose twigs, light green-drying leaves with white ascending hairs, and small green flowers.  In the original description of Rhodostemonodaphne leptoclada (Madriñán, 1996), I included three collections (de Granville et al. 12377, 12383 & 12457) from the Tumucumaque range (N Amapá, Brazil on the border with French Guiana) as conspecific with the individual from La Fumée.  I noted considerable differences between them but cited the collection from Mt. St. Marcel as an intermediate.  These specimens are now excluded from R. leptoclada and are considered a new species R. tumucumaquensis (see above).

A new species from Manaus, R. parvifolia, is very similar to the type of R. leptoclada.  They both have slender twigs, although in R. parvifolia these are soon glabrescent.  The leaves of R. parvifolia are considerably smaller that those of R. leptoclada, and are glabrous, yet both species have thin, long petioles, a minutely but conspicuously decurrent lamina, slender inflorescences, and flowers that are very much alike in both perianth and androecial characters.  These similarities suggest a close relationship between these two species.

As originally noted, the collections from the Tumucumaque range have shorter, thicker petioles, and larger bullate leaves than those of either Rhodostemonodaphne leptoclada and R. parvifolia.  Furthermore, R. leptoclada has thick, adaxially tomentose tepals, while the Tumucumaque specimens are thinner and adaxially glabrous.  The presence of persistent tepals on the cupule of the fruiting R. parvifolia suggests that the yet unknown fruits of R. leptoclada may have persistent tepals–-the tepals and androecium of the Tumucumaque specimens dehisce in a ring after anthesis, and so the cupule presumably has a straight margin.  Based on these differences I have described the specimens from the Tumucumaque range and Mt. St. Marcel as a new species, R. tumucumaquensis.