Monographs Details: Bactris ptariana Steyerm.
Description:Species Description - Stems solitary or cespitose, 2-3(-9) m tall, 3-5 (-10) cm diam., spiny on internodes. Leaves 5-9; leaf spines distinctly clustered, black, somewhat flattened, pilose except at base, spinulose, 1-3 cm long, dense on sheath and on lateral surfaces of petiole, fewer on rachis; sheath 20-76 cm long; ocrea not seen; petiole 15-40(-80) cm long; rachis 1-2 m long; pinnae 15-47 per side, irregularly arranged in clusters but spreading in more or less the same plane, linear or linear-lanceolate, acuminate, sometimes strongly plicate, sparsely to densely spinulose abaxially; middle pinnae 44-65 × 2.5-5 cm (the apical pinna wider than the others). Inflorescences infrafoliar, borne among the persistent leaf bases; peduncle 11-24 cm long, recurved, spiny; prophyll 7-12 cm long; peduncular bract 12-8 cm long, sparsely to densely covered with appressed, black spines to 1 cm long; rachis 2-5 cm long; rachillae 12-25, 6-17 cm long, at anthesis densely covered with short, brown or white, flexuous trichomes; triads irregularly arranged almost to apex of rachillae among paired or solitary staminate flowers; staminate flowers 3-4 mm long; sepal lobes ca. 1 mm long; petals 3-4 mm long; stamens 6; pistillode absent; pistillate flowers 3-3.5 mm long; calyx annular, 0.5 mm long, glabrous or pilose; corolla cupular, 2-2.5 mm long, densely spinulose; staminodes absent; fruits 0.7-1 × 0.6-0.8 cm, obovoid, rostrate, bright orange or red, rarely minutely spinulose; mesocarp starchy; endocarp turbinate, the sterile pores slightly displaced longitudinally; endocarp fibers absent or present and adherent to endocarp; fruiting perianth with obscure calyx and lobed, tomentose corolla, without staminodial ring.
Discussion:Bactris ptariana is diagnosed by its clustered, black, pilose leaf spines, rachillae densely covered with short, brown or white, flexuous trichomes, and obovoid fruits. It is so similar to Bactris balanophora, especially in its clustered, pilose leaf spines, rachillae densely covered with trichomes, and fruit with adherent endocarp fibers, that it is hard to imagine they are not related, or even conspecific (although placed in different clades by Sanders, 1991). Specimens from higher elevations (1000-2000 m) in Bolivar, Venezuela differ from the lowland specimens from Guyana in their plicate, linear pinnae that are densely spinulose abaxially, and their larger inflorescences. As far as can be judged from the specimens available, this variation is continuous with elevation.
Distribution:Venezuela South America
| Bolívar Venezuela South America
| Guyana South America