Roupala obtusata Klotzsch

Authority

Prance, Ghillean T., et al. 2007. Proteaceae. Fl. Neotrop. Monogr. 100: 1-218. (Published by NYBG Press)

Family

Proteaceae

Scientific Name

Roupala obtusata Klotzsch

Type

Type. Guyana. Locality not known, date not known (fl, fr), Rich. Schomburgk 215 (holotype, B, photo 11763 F, GH, K, MO).

Synonyms

Roupala angustifolia Diels, Roupala obtusata var. obovata Huber

Description

Species Description - Tree, (2-)3-10(-20) m tall, 10-50 cm diam., or rarely a scandent shrub. Branch bark light brown or gray superficially, dark red-gray or gray beneath, glabrous except rufous axillary buds of short, appressed hairs. Lenticels numerous, minute, <0.5 mm diam., raised peripherally, granular, red-brown. Leaves simple, or rarely with bisected midrib or extralaminal tissue as evidence of lobing, thinly coriaceous, drying pale green, green-brown, or brown and usually shiny above, glabrous even when new. Petiole not well defined, (0.5-)1-2.5(-3) cm long, 1-2.5 mm broad at midlength, 1/4-1/8.4 the length of the lamina, smooth to slightly rugose, flat adaxially due to lamina sides descending (curving from the petiole sides to the adaxial petiole surface), terete lower down, a scar often developing between branch and petiole (not stipular), glabrous. Lamina (4.5-)7-15(-21) × 2-6(-7) cm, length to breadth ratio (1.5-)2-4(-5):l, predominantly narrowly oblong, lanceolate or elliptic, also oblong, oblanceolate, narrowly obovate, or widely elliptic; base cuneate, more rarely acute- or obtuse-decurrent, symmetrical; apex obtuse to rounded, attenuate or acute, the apical point of midrib not protruding; margin always entire, revolute towards the base of the leaf; venation raised on both surfaces of lamina, ± conspicuous above, conspicuous below, the tertiary venation faint to obscure beneath, appearing eucamptodromous above, semicraspedodromous below where detail is seen more clearly, sometimes forming a double marginal vein, with a strong inner vein and weaker outer vein, the midvein reaching the apex; lateral veins (4-)6-8(-10) pairs. Inflorescence 5-12(-17)× (1.5-)2-3(-3.5) cm, axillary, rarely lateral, unbranched, glabrous, often shiny, the flowers clustered together or well spaced; peduncle 1-2(-3) cm × 1-1.5 mm, a few sterile bracts persistent. Common bracts 0.3-0.5(-0.7) × 0.3-0.6 mm, glabrous except for fimbriate margin and apex of orange- to red-brown hairs. Flower-pair axis absent, rarely 0.5-1.5 mm long. Pedicels l-2.5(-4.5) × 0.5-0.8(-l) mm, glabrous. Buds 1-1.5 mm broad at the apex, 0.5-1 mm broad at midlength, glabrous or occasionally with short, weak hairs. Flowers 6-12(-14) mm long; filaments 00.5 mm long, adnate 4-9 mm from base of tepals; anthers 2-4.5 × 0.3-0.5 mm; nectary lobes 0.3-0.5mm long, closely appressed giving the appearance of a ring; ovary somewhat compressed longitudinally, the ovary hairs extending (0.7-)l-1.5(-2.5) mm from base of ovary, extending slightly lower on one side, very short, yellowish to light ferruginous, closely appressed, the ovary sometimes glabrous; ovules 0.5-l × 0.2-0.3 mm. Infructescence (5-)9-15 cm long, glabrous; fruit pedicels 2.5-6 × 1-1.5 mm, glabrous. Fruit 2.8-3.8 × 1.2-1.6 cm, both sides curved more or less equally, less commonly with sutured side curved more strongly than unsutured side, the base markedly constricted for (3-)5-7mm length, apex straight to curved to an angle perpendicular to unsutured side, constricted only 1-1.5 mm, the style persistent forming sharp apex, the surface conspicuously ridged due to underlying vascular tissue, the marginal vein generally protruding throughout periphery, beige to black, glabrous even when immature. Seeds 2.1-2.4 × 1.2 cm.

Discussion

Diagnostic characters. An elegant plant with elliptic to oblong leaves, entire leaf margins, and which is essentially glabrous throughout. The ovary is slightly compressed longitudinally and is covered by an extremely short and appressed indumentum which extends higher on one side than the other, rarely entirely glabrous. May be confused with Roupala nitida, R. montana, or R. consimilis in the leaves.

Field characters. Tree (2-)3-10(-20) m tall and 10-50 cm diam., or rarely a scandent shrub. Wood hard, heavy, reddish. Flower buds greenish. Flowers white, cream, yellowish-white, or greenish-white with faint sweet smell. Fruit green maturing brown to black

Roupala obtusata is most similar to Roupala consimilis, which is distributed distantly in the Atlantic forest remnants of eastern Brazil.

Phenology. Flowering and fruiting predominate from Apr to Sep as the Amazonian waters reach peak flood; less commonly flowering Oct-Dec and Feb-Mar, with no records at all for Jan.

Distribition and Ecology: This species is found from 4° N of the equator in Amazonian Venezuela and Colombia to 15° S in Mato Grosso, and 56-67° W. It occurs along rivers that drain into the Amazon, excepting a minority of specimens collected along the Río Sipapo, which drains into the Orinoco, as well as the type collection from an unknown locality in Guyana. The species is almost exclusively found in igapó on white sand (rarely clayey-stony soil) below 300 m alt., recorded only rarely in terra firme forest, indundated caatinga in Amazonian Brazil, and scrub savanna in Amazonian Venezuela.

Distribution

Brazil South America| Mato Grosso Brazil South America| Amazonas Brazil South America| Guyana South America|