Bactris acanthocarpa Mart.

  • Authority

    Henderson, A. 2000. (Palmae). Fl. Neotrop. Monogr. 79: 1-181. (Published by NYBG Press)

  • Family

    Arecaceae

  • Scientific Name

    Bactris acanthocarpa Mart.

  • Type

    Type. Brazil. Bahia: Ilheus, s.d., C. Martius s.n. (holotype, M; F neg. 18600).

  • Description

    Species Description - Stems solitary or less often cespitose and then with 2-5 or more stems per clump, 0.1-1.5 m tall (rarely taller on old plants), 3-6 cm diam., sometimes procumbent, seldom spiny on internodes, usually covered with persistent, decaying leaf bases. Leaves 5-15; leaf spines mostly solitary and scattered, black, sometimes somewhat flattened, to 8(-15) cm long, on sheath and lateral surfaces of petiole, denser on proximal part of petiole, usually absent from rachis; sheath 10-50 cm long; ocrea to 10 cm long; petiole 0.4-1.7 m long; petiole and rachis reddish brown-tomentose abaxially; rachis 0.6-3.1 m long; pinnae (3-) 12-33 per side, irregularly arranged in clusters of 2-4, spreading in slightly different planes, linear-lanceolate or sigmoid, long-acuminate, usually with prominent cross-veins; middle pinnae 20-60 x 3-10 cm; apical pinna usually wider than others. Inflorescences interfoliar, often hidden among persistent leaf bases and debris; peduncle 10-20 cm long, straight or slightly curved, usually not spinulose, sometimes scarcely to densely spinulose; prophyll 6-14 cm long; peduncular bract 20-40 cm long, moderately to densely covered with black spines to 1 cm long, sometimes more or less glabrous, persistent over infructescence and rotting at base as fruits develop; rachis 2-5 cm long; rachillae 10-46, 4-12 cm long, filamentous, at anthesis covered with brown, moniliform trichomes; triads more or less regularly arranged (but often with solitary staminate flowers interspersed) on proximal ca. half or more of rachillae, and there tending to be absent from adaxial side of rachillae (paired or solitary staminate flowers only on distal ca. half of rachillae); staminate flowers to 3 mm long, deciduous; sepal lobes 0.5-1 mm long; petals 2.5-3 mm long; stamens 6; pistillode absent; pistillate flowers 2-3 mm long; calyx urceolate, 1-3 mm long, glabrous or with small, brown scales; corolla urceolate, 2-4 mm long, glabrous, or with a few small, brown scales, or occasionally with spinules, glabrescent; staminodes absent; fruits 1-2.3 cm diam., broadly obovoid, shortly rostrate, orange or red, with deciduous, flexuous spinules; mesocarp starchy; endocarp obovoid, the sterile pores slightly displaced longitudinally; endocarp fibers few or absent; fruiting perianth with short, 3-lobed, glabrous calyx and longer, 3-lobed, glabrous corolla, without staminodial ring.

  • Discussion

    Bactris acanthocarpa is diagnosed by its short stem, irregularly arranged pinnae, filamentous rachillae without spinules, and pistillate flowers with the calyx almost as long as the non spinulose corolla. Synonymy was established by Wessels Boer (1965, 1988) and Henderson (1995). Bactris fragae was included as a synonym of B. setosa by Henderson et al. (1995); it actually belongs under B. acanthocarpa var. exscapa. Martius’s original description appears to have been based on a mixture of two species, with the leaves incorrectly described (Noblick, 1991). The description was emended by Henderson (1995). The type itself consists of an infructescence only, but recent collections from the type locality leave little doubt as to the application of this name.

    Bactris acanthocarpa is a widespread and variable species. Specimens from the Atlantic coastal forest of Brazil have long, sigmoid pinnae and inflorescences with a spinulose peduncle, and I recognize these as var. acanthocarpa. Specimens from the northeastern Amazon region, in Suriname, French Guiana, and Brazil (Amazonas, Para), have shorter, sigmoid pinnae. These are recognized as var. intermedia, following Henderson (1995). Around the periphery of the range of the latter variety, in Guyana, Venezuela (Amazonas, Bolivar), and Brazil (Maranhão, Pará), some specimens are somewhat intermediate, in pinna shape and size, with larger plants with longer, linear-lanceolate pinnae in the central and western Amazon region. I recognize these intermediates and the larger plants as var. exscapa. The intermediates could be used as evidence to recognize just one instead of two varieties. The only reason I have not done so is that in some places both grow together and are quite distinct and obviously behave as separate taxa. Some scattered plants have simple leaves, and these were called Bactris trailiana by Henderson (1995). I here recognize these at the varietal rank, as B. acanthocarpa var. trailiana. This variety is somewhat doubtful, and most specimens appear to be merely simple-leafed forms of var. exscapa. Indeed, in some cases individual plants may have both simple and pinnate leaves.

    Although four varieties of Bactris acanthocarpa are here recognized, B. rhaphidacantha appears similar morphologically, and perhaps also should be recognized as a variety of the former species.

    Some specimens of Bactris acanthocarpa are unusual and are not included in the description nor the list of specimens examined. Two of them (Brazil, Para: Mun. Barcarena, Agua Verde, 1° 35' S, 48° 45' W, 5-10 m, 20 Oct 1994, Noblick & Guedes 5027 (K, NY), Noblick & Guedes 5028 (NY)) have stems to 10 m tall, scattered triads, pistillate flowers with the calyx much shorter than the corolla, and the latter has simple leaves. They could be hybrids between B. acanthocarpa and another species. Two other specimens (Brazil. Para: Santarem-Cuiaba rd., BR 163, km 934 from Santarem, 13 Nov 1977, Balick et al. 924 (BH, INPA, NY). Mato Grosso: Fazenda Cachimbo, sub-base of Projeto Radam, 25 Nov 1976, Cordeiro 1200 (MG)) have inflorescences typical of var. exscapa, but were reported to have stems to 6 m tall.

    Wessels Boer (1971) reported a hybrid, Bactris × moorei Wessels Boer, between Bactris acanthocarpa (as B. humilis) and B. oligoclada in Venezuela (Type. Venezuela. Bolivar: Near El Palmar, 8° 5' N, 61° 50' W, 75 m, 25 Nov 1967, Wessels Boer 2092 (holotype, U; isotype, MER)).

  • Distribution

    Common and widespread in the Amazon region and Atlantic coastal forest, in lowland rain forest on terra firme, usually below 300 m elevation but occasionally to 1000 m.

    Brazil South America|