Monographs Details: Rhodostemonodaphne negrensis Madriñán
Authority: Madriñán, Santiago R. 2004. (Lauraceae). Fl. Neotrop. Monogr. 92: 1-102. (Published by NYBG Press)
Description:Latin Diagnosis - Species foliis magnis discoloribus supra plerumque ma-culatis, venatione infra conspicue pallida et cupula tepalis persistentibus a congeneris diversa.

Species Description - Trees: branching unknown; twigs angular, soon becoming terete, 4-5 mm diam.; epidermis brownish to black, barely visible due to indument cover; terminal bud plump, ca. 5 X 3 mm; cataphylls persisting on current flush or caducous, to 1.2 mm long; indument puberulous, caducous after one flush, the hairs dense, to 0.2 mm long, straight, erect, brownish. Leaves: petioles robust, 1.3-2.5 cm X 2.2-5 mm, adaxially flattened; blades chartaceous, flat to undulate, broadly ovate to elliptic, 15-34 X 6-19 cm; base obtuse to rounded, 60-160°; apex acute to rounded, 90-140°, ultimately acuminate for up to 2.5 cm; margin plane; primary vein above flat to raised, below prominent; secondary veins 6-10 pairs, equidistant, brochidodromous, above raised to impressed, below raised, diverging at 45-65°, evenly arching, chordal angle 20-30°, the angle uniform along blade length; tertiary veins above impressed, below slightly raised, random-reticulate to scalariform; higher-order veins above flat to slightly raised, below slightly raised; surface above olive-green to light brown, often mottled, the veins darker, below yellowish brown to brown, the veins lighter; indument above puberulous, the primary and secondary veins tomentose, caducous by next flush, below puberulous, the hairs sparse, to 0.5 mm long, straight, erect, yellowish, persisting for at least two flushes. Staminate inflorescences: along whole length of flush, erect to pendulous?, peduncles 4-16 cm long, the hypopodia 1-5 cm x 1.5-2.5 mm, branch orders 3-6, the second-order branches 7-12, dispersed, lowest branch to l(-3) cm long, color and indument of all axes as on twigs; bracts and bracteoles caducous (not seen). Staminate flowers: pedicels ca. 4 X 0.8 mm, the diameter even throughout; receptacle obconical, ca. 1.5 X 3.2 mm; tepals coriaceous, ob-ovate, ca. 4 X 3.2 mm (inner whorl slightly smaller), at anthesis spreading to recurved, reddish, somewhat translucent, adaxially puberulous to tomentose; stamens of whorls I and II spathulate, the anthers trapezoid, ca. 1 X 1.4 mm, with a few hairs at base, the locelli 4, apical, in a strong arch, introrse, the glands absent; whorl III columnar, ca. 1.4 X 0.8 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 filiform, ca. 0.5 X 0.2 mm, hairy. Pistillate flowers: pistil ca. 3.2 x 1.2 mm; ovary ovoid, ca. 1.6 mm long, hairy. Fruits: pedicels to 1 x 5 mm, gradually enlarging to form the cupule; cupule trumpetshaped, to 10 x 20 mm, wrinkled, the margin undulate, tepals persisting; berry elliptic, to 25 x 15 mm.

Discussion:Field notes. Trees to 12(-15) m tall and 15(-20) cm diam., already flowering when 5 m tall (but see discussion); outer bark smooth (with minute scales and irregularly fissured); inner bark ca. 4 mm thick, yellowish brown; wood light yellowish brown, wood aromatic. Inflorescence axes reddish; tepals orange to purple. Cupule red.

Etymology. Named after the Rio Negro.

Rhodostemonodaphne negrensis is a low tree, with large leaves that are mottled (at least when dry), often glaucous abaxially, and with conspicuously light-colored secondary and tertiary venation. Its large flowers are similar only to those of R. dioica and R. saülensis, yet in addition to other vegetative differences, the indument of the former is yellow tomentose, with appressed and erect hairs, while that of the latter is silver sericeous.

A collection from the upper Rio Cuieras (a tributary of the Rio Negro) from an open forest (Prance et al. P.17721) is included here with hesitation. It was taken from a low shrub 2 m tall; its leaves, although similar in shape and color to those of other collections of the species, are completely glabrous, have shorter petioles, and secondary venation with the loops more distant from the margin. The buds of the pistillate flowers are much smaller than the buds of the only other known pistillate flowering individual (Vicentini et al. 628), the staminodes of whorls I and II have their lower locelli latrorse, and the pistil is globose with a very short style. Having seen only pistillate material in bud, I cannot be sure of its identity, yet based on its foliar characters and geographical distribution it may in fact belong to R. negrensis.

The collection Kawasaki 179, from the Uaupés river, a tributary of the Rio Negro, differs from the other collections in that it has more angular twigs, sparser indument, and broader, nearly glabrous leaves. The flowers, however, are like the other collections of this species.
Distribution:Brazil South America| Amazonas Brazil South America|