16. Rhodostemonodaphne revolutifolia

Rhodostemonodaphne revolutifolia Madriñán

Brittonia 48: 55, figs. 5 & 6. 1996. Type. French Guiana. Crique Arataye, Nouragues station, 8 Aug 1990 (stam. fl), Sabatier 3500 (holotype, NY; isotypes, K, MO).

Description

Trees: branches basitonic, in axils of cataphylls; twigs terete, 2–5 mm diam.; epidermis black, barely visible due to indument cover; terminal bud plump, ca. 6 X 4 mm; cataphylls persisting on current flush, up to 6 mm long; indument pubescent, persisting for at least two flushes, the hairs dense, up to 1 mm long, straight to crisped, erect, yellowish. Leaves: petioles pulvinate, 0.5–1.9 cm X 1.2–2.8 mm, terete; blades chartaceous, flat to bullate, narrowly elliptic, 6–18(–22) X 3–7(–19) cm; base acute, 40–60°; apex attenuate, 70–80°, ultimately acuminate for up to 1.3(–1.5) cm; margin revolute; primary vein above slightly raised and rounded, below prominent; secondary veins 3–6(–7) pairs, equidistant, eucamptodromous, above slightly raised, below prominent, diverging at 55–60(–70)°, evenly arching, chordal angle 20–30°, the angle uniform along blade length; tertiary veins above and below slightly raised, random-reticulate; higher order veins on both sides slightly raised; surface above yellowish-brown in younger leaves, olive-green in older leaves, below greenish-brown, slightly glaucous, the veins yellowish to brown; indument above absent, the primary and secondary veins tomentose, below pubescent, the hairs dense, up to 1 mm long, straight, erect, yellowish, denser on the veins, persisting for at least two flushes. Staminate inflorescences: basitonic, pendulous, peduncles 12–17 cm long, the hypopodia 5–9 cm X 1–1.2 mm, branch orders 5, the second-order branches 4–5, dispersed, lowest branch up to 4.5 cm long, all axes greyish to blackish, puberulous; bracts persistent, up to 0.9 mm long, spoon-shaped, reflexed adaxially hairy; bracteoles persistent, up to 0.7 mm long, adaxially hairy. Staminate flowers: pedicels ca. 5.6 X 1 mm, the diameter even throughout; receptacle flat, ca. 2 X 4.8 mm; tepals chartaceous, ovate, ca. 4.2 X 4.2 mm (inner whorl slightly smaller), at anthesis forming a cup ca. 6.0 mm diam. erect, reddish-gray, adaxially tomentose; stamens of whorls I and II, the anthers sessile, chubby, broadly elliptical, ca. 1.8 X 3.2 mm, with a few hairs at base, the locelli 2, apical, introrse, the glands absent; whorl III columnar, ca. 1.2 X 1 mm, with a few hairs at base, the locelli 4, the upper pair latrorse, the lower pair extrorse, the glands globular, ca. 1.2 mm diam.; whorl IV absent; all stamens reddish; pistillode absent (minute, up to 0.6 mm long). Pistillate flowers: pistil ca. 1.7 X 0.8 mm; ovary ovoid, ca. 0.8 mm long, glabrous. Fruits unknown.

Field notes

Trees up to 12–15 m tall and 10–12 cm diam.; buttresses small; outer bark smooth (thin, fragile, finely fissured and chipped), brownish-red in section; inner bark ca. 3 mm thick, somewhat fibrous, pale yellow; wood yellow, wood aromatic. Tepals yellowish.

Distribution (Figure 11)

Known from two collections from central French Guiana, at 100–350 m elev., in rain forest.  Both flowering collections were made in the month of August, at the beginning of the dry season.

Additional specimens examined

French Guiana: Fleuve Sinnamary, above Petit Saut, 28 Aug 1993 (pist. fl), Mori et al. 23416 (CAY n.v., GH, MO, NY, P).

Discussion

Vegetatively R. revolutifolia is a very distinctive species with conspicuously revolute leaves, a rare condition in the family.  The inflorescences are distinctly cymose, with persisting recurved, bracts and bracteoles.  The most striking feature of the species is the two-locellate outer stamens of the staminate flowers.  The vestigial four-locellate staminodia of the pistillate flowers, however, relate this species to other four-locellate dioecious species, i.e., Rhodostemonodaphne.

Contact | Updated 28.07.2005 | ©2005 Santiago Madriñán