Desmoncus parvulus L.H.Bailey, Bull. Torrey Bot. Club 75: 115 (1948)

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Distribution

From 4°05'S-8°20'N and 45°19'-72°12'W in the eastern and central Amazon region in Brazil, the Guianas, Venezuela, and Colombia at 209(5-650) m elevation in lowland rainforest .

Discussion

  • Taxonomic notes:-The name Desmoncus macroacanthos Martius was used by Wessels Boer (1965) for specimens included here. This name is here treated under Excluded Names; the sterile type has spiny leaf sheaths and non-spiny cirri and does not appear to represent this species. The name Desmoncus phoenicocarpus Barbosa Rodrigues was used for this species by Henderson (1995). The type is an illustration, also having spiny leaf sheaths and non-spiny cirri, and is also here treated under Excluded Names.
    Subspecific variation:-Specimens come from widely scattered localities but this may be an artifact of insufficient collecting. Two specimens from the Rio Tapajos in Brazil are unusual. One (Maciel 167) has very short petiole, numerous, small pinnae, and cirrus without spines abaxially throughout; the second (Anderson 10577) has very large pinnae. These may be of hybrid origin. (Henderson, A. 2011: A revision of Desmoncus (Arecaceae). – Phytotaxa 35: 1-88)A

Description

  • Plants 4.4(1.5-10.0) m tall; stems 0.8(0.4-1.8) cm diameter, clustered. Leaf petioles 6.0(0.7-13.8) cm long; rachises 31.7(22.5-47.0) cm long, 2.7(1.7-3.8) mm wide, the spines usually <1 cm long, mostly abaxial, recurved with markedly swollen bases; pinnae 6(4-9) per side of rachis, without long, filiform apices, without a beard of spines at the bases, with uneven surfaces at the bases adaxially, usually covered with spinules and/ or dense tomentum; basal pinna 10.8(4.2-22.0) cm long, 3.0(1.0-5.8) cm wide; cirri well-developed, with acanthophylls, with few spines abaxially throughout, with no intermediate acanthophylls present, usually with a wide gap between pinnae and acanthophylls (i.e., gap wider than that between adjacent acanthophylls). Inflorescences with the rachis angular, slightly twisted, thicker than the few to numerous, closely spaced and spirally arranged rachillae, each rachilla not (or very rarely) adnate to the rachis, subtended by an acute bracteole and with a well-developed axillary pulvinus; peduncles 1.6(1.0-3.1) mm wide; peduncular bracts 12.5(8.5-17.0) cm long, broad, ridged, densely covered with short, straight, swollen-based, vertically oriented spines, these terete, whitish-brown proximally, brown distally, without tomentum; rachillae 9(7-14), glabrous or scarcely tomentose initially; proximal rachillae 4.6(3.0-6.2) cm long, 0.7(0.5-0.9) mm wide; stamens 6; fruits 11.1(8.9-14.3) mm long, 9.4(7.1-11.2) mm wide, the surfaces uneven with numerous, subepidermal, long, branching fibers; fruiting corollas less than one quarter as long as fruits, splitting irregularly into 3 lobes, the lobes often splitting again; endocarps globose to obovoid with rounded or slightly peaked apices, the pores lateral. (Henderson, A. 2011: A revision of Desmoncus (Arecaceae). – Phytotaxa 35: 1-88)A

Bibliography

    A. Henderson, A. 2011: A revision of Desmoncus (Arecaceae). – Phytotaxa 35: 1-88