Bactris tomentosa Mart., Hist. Nat. Palm. 2: 100 (1826)

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Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)
Brazil Northpresent (World Checklist of Arecaceae)A
Brazil Northeastpresent (World Checklist of Arecaceae)A
French Guianapresent (World Checklist of Arecaceae)A
. French Guiana and Brazil (Amapá, Amazonas, Maranhão, Pará). lowland rain forest on terra firme at low elevations.

Discussion

  • Bactris tomentosa is diagnosed by its scattered, yellowish, somewhat flattened, leaf spines, inflorescence with 1 rachilla with regularly arranged triads almost throughout, purple-black fruits, and numerous endocarp fibers with juice sacs attached. Synonymy was established by Henderson (1995). Henderson recognized two varieties (var. tomentosa and var. sphaerocarpa) of a broadly conceived B. tomentosa. These are here recognized at the species level.
    The specimens cited are variable, and could represent two or even three taxa. Near Manaus there are specimens with pilose pinnae and spinulose pistillate perianths and fruits. These were called B. tomentosa by Martius. In the same region are similar plants, but with the leaves less pilose and the perianth and fruits non-spinulose. These were called B. eumorpha by Trail. Towards the east, in Brazil and French Guiana, plants only rarely have minutely spinulose fruits, and resemble B. maraja, except for the inflorescence with 1 rachilla. This problem cannot be solved without more collections.

Description

  • Stems cespitose, 0.3-3 m tall, 0.8-1.6 cm diam., spiny on internodes. Leaves 8-13; leaf spines scattered, yellowish, somewhat flattened, to 3 cm long, sparse to moderate on sheath and petiole; sheath 11-25 cm long, sheath, petiole, and rachis brown-tomentose; petiole 10-28(-50) cm long; rachis 18-55(-90) cm long; pinnae 2-11 per side, irregularly arranged in clusters, spreading in slightly different planes, sigmoid, with long, filamentous, minutely spinulose apex, occasionally pilose abaxially, rarely adaxially, or blade simple or with a few pinnae, then deeply bifid apically and narrowly cuneate basally; blade to 50 cm long and 15 cm wide at apex of rachis, pinnate leaves with middle pinnae 18-27 x 3-5 cm (the apical ones wider than the others). Inflorescences interfoliar; peduncle ca. 6 cm long, scarcely recurved, not spiny; prophyll 7-9 cm long; peduncular bract 10-20 cm long, not spiny or spiny with short, black spines to 0.3 cm long or flexuous, yellowish spines to 0.8 cm long; rachilla 1, 3-5 cm long, at anthesis densely covered with brown trichomes; triads regularly arranged almost throughout rachilla; staminate flowers 6-7 mm long; sepal lobes 1-2 mm long; petals 6-7 mm long; stamens 6-9; pistillode absent; pistillate flowers 3.5-4 mm long; calyx tubular, 3-4 mm long, occasionally spinulose; corolla tubular, 3-4 mm long, occasionally spinulose; staminodes minute or absent; fruits to 2 x 1.5 cm, broadly obovoid, purple-black, occasionally spinulose; mesocarp juicy; endocarp turbinate but ridged apically, the sterile pores displaced longitudinally; endocarp fibers numerous, free, with juice sacs attached; fruiting perianth with lobed calyx half as long as the lobed, occasionally spinulose corolla, without staminodial ring.

Bibliography

A. World Checklist of Arecaceae