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Flora of the Venezuelan Guayana

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9. MAHUREA Aubl., Hist. Pl. Guiane 558, t. 222. 1775.

by Bruce K. Holst and Klaus Kubitzki

Shrubs or medium-sized trees; wood reddish; terminal buds with scales; indument simple. Leaves alternate, petiolate; blades with pinnate secondary veins connected by numerous subparallel tertiary veins; stipule-like colleters sometimes present. Inflorescences panicles or racemes. Flowers bisexual, pink, without scent. Sepals 5, quincuncial; petals 5, contorted. Stamens numerous, persisting after anthesis; filaments slender, connate at the base; anthers versatile, attached near base, elongate, 4-sporangiate, opening longitudinally, the connective broad and protruded into a cupulate subapical gland. Ovary glabrous, ovoid, 3-locular, each locule with 2 elongate placentas with numerous imbricate ovules; style simple; stigma 3-lobed. Capsule shortly stipitate, from the top septicidally dehiscent and leaving a subulate columella with thickened placentas, the valves woody, thickened, the septas thin. Seeds numerous, linear, sawdust-like; testa prolonged into a wing at the top and at the base; albumen sparing; embryo lateral, linear, terete.

Colombia, Venezuela, Guyana, French Guiana, Peru, northern Brazil; 2 species, 1 in Venezuela.

The second species, Mahurea palustris Aubl., occurs in coastal French Guiana and adjacent Brazil.

Mahurea exstipulata Benth., London J. Bot. 2: 365. 1843.

?Mahurea casiquiarensis Benth., J. Proc. Linn. Soc., Bot. 5: 64. 1861.

Shrub or medium-sized tree to 12(-20) m tall; flowers pink, showy. Colombia, Venezuela, Guyana, Suriname, French Guiana, Peru, Brazil (Amazonas); 2 subspecies, both in the flora area.

The type of Mahurea casiquiarensis Benth., Spruce 3161, is intermediate in some respects to the two subspecies recognized. Though M. exstipulata subsp. exstipulata is largely limited to Bolívar in the flora area, some transitional forms with subsp. duckei have been noted in scattered localities in Amazonas.

Key to the Subspecies of M. exstipulata

1. Leaves broadly lanceolate, obovate-spatulate, or oblong, ca. 2.4 times longer than broad; style thickened below stigma; Amazonas state ..... subsp. duckei

1. Leaves narrowly lanceolate, 3-5 times longer than wide; style not thickened below stigma; Bolívar state ..... subsp. exstipulata

M. exstipulata subsp. duckei (Huber) Kubitzki, Mem. New York Bot. Gard. 29: 138. 1978. -Mahurea duckei Huber, Bol. Mus. Goeldi Paraense Hist. Nat. Ethnogr. 7: 300. 1913.

Mahurea tomentosa Ducke, Arq. Inst. Biol. Veg. 1: 208. 1935.

Periodically flooded forests or nonflooded forests along rivers, 100-300 m; Amazonas (Río Cataniapo, Río Negro, upper Río Orinoco). Colombia, Guyana, Suriname, French Guiana, Peru, Brazil (Amazonas).

M. exstipulata subsp. exstipulata

Mahurea linguiformis Tul., Ann. Sci. Nat. Bot. sér 3, 8: 340. 1847.

Mahurea sororopantepuiana Steyerm., Fieldiana, Bot. 28: 395, fig. 81. 1952.

Evergreen lowland to montane and riparian forests, borders of periodically burned savannas, tepui slopes, low tepui summits, 100-1600(-2200) m; Bolívar (Gran Sabana, upper Río Cuyuní basin, Sororopán-tepui). Guyana, Brazil (Roraima). Fig. 217.


Scientific Comments:
Paul Berry (peberry@facstaff.wisc.edu) or Kay Yatskievych (kay.yatskievych@mobot.org).

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