Desmoncus pumilus Trail, J. Bot. 14: 353 (1876)

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Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)
Brazil Northpresent (Henderson, A., A revision of Desmoncus (Arecaceae) in Phytotaxa 35. 2011)A
Colombiapresent (Henderson, A., A revision of Desmoncus (Arecaceae) in Phytotaxa 35. 2011)A
From 1°29'N-7°44'S and 59°50'-71°10'W in the Brazilian Amazon (Amazonas, Roraima) and just reaching Colombia (Amazonas) at 75(57-92) m elevation in campina or campinarana vegetation. (Henderson, A., A revision of Desmoncus (Arecaceae) in Phytotaxa 35. 2011)A

Discussion

  • Taxonomic notes:-This species appears most similar to D. mitis, with which it shares slender inflorescences and uneven fruit surfaces Y-shaped fibers.
    Subspecific variation:-There is geographic disjunction but there are too few specimens (only 12) to test for differences. The species occurs in widely scattered areas in the central and western Amazon in campina or campinarana vegetation. It comprises small palms with short, slender stems. The specimens from different areas are quite different from one another and there seems a possibility that there is more than one taxon here, but many more specimens are needed to decide the matter. Two specimens (dos Santos 75, Rabelo 87) have pinnae bases with small spines but these appear different from the pinnae bases of D. mitis (pinnae bases with uneven surfaces at the bases adaxially, usually covered with spinules and/or dense tomentum). Some specimens (Calderon 2709, Carvalho 2149, Cid 10996, dos Santos 757) have distal pinnae intermediate between acanthophylls and more usual pinnae, almost like those of D. chinantlensis and similar species. (Henderson, A., A revision of Desmoncus (Arecaceae) in Phytotaxa 35. 2011)A

Description

  • Plants height 4.0(3.0-5.0) m; stems 0.5(0.3-0.7) cm diameter. Leaf petioles 1.7(0.5-8.0) cm long; rachises 23.1(10.0-42.5) cm long, 2.6(1.9-4.4) mm wide, the spines usually <1 cm long, mostly abaxial, recurved with markedly swollen bases; pinnae 7(2-15) per side of rachis, without long, filiform apices, without a beard of spines at the bases, without spinules or dense tomentum at the bases adaxially; basal pinna 9.1(4.3-18.7) cm long, 0.9(0.3-2.2) cm wide; cirri well-developed, with acanthophylls, with few spines abaxially mostly on proximal part only, with or without intermediate acanthophylls present. Inflorescences with the rachis smooth, not twisted, narrower than the few, distantly spaced and alternate rachillae, each rachilla usually briefly adnate proximally to the rachis and with an irregular bracteole displaced onto the rachis, with or without an axillary pulvinus; peduncles 1.1(0.8-1.6) mm wide; peduncular bracts 16.3(14.0-22.5) cm long, narrow, elongate, ribbed, scarcely brown tomentose, without spines (rarely with few spines); rachillae 4(2-5), glabrous or scarcely tomentose initially; proximal rachillae 3.5(2.5-6.0) cm long, 0.8(0.5-1.1) mm wide; stamens 7; fruits 10.0(8.2-11.6) mm long, 6.7(5.0-8.5) mm wide, the surfaces uneven with numerous, subepidermal, short, often branching (Y-shaped) fibers; fruiting corollas less than one quarter as long as fruits, splitting irregularly into 3 lobes, the lobes often splitting again; endocarps narrowly ellipsoid with rounded apices, the pores lateral. (Henderson, A., A revision of Desmoncus (Arecaceae) in Phytotaxa 35. 2011)A

Bibliography

    A. Henderson, A., A revision of Desmoncus (Arecaceae) in Phytotaxa 35. 2011