Desmoncus leptoclonos Drude, Fl. Bras. 3(2): 315 (1881)

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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
Brazil Southeastpresent (Henderson, A., A revision of Desmoncus (Arecaceae) in Phytotaxa 35. 2011)A
Brazil West-Centralpresent (Henderson, A., A revision of Desmoncus (Arecaceae) in Phytotaxa 35. 2011)A
Paraguaypresent (Henderson, A., A revision of Desmoncus (Arecaceae) in Phytotaxa 35. 2011)A
From 12°49'-23°20'S and 48°03'-58°27'W in the Cerrado region of Brazil (Goiás, Mato Grosso, Mato Grosso do Sul, Minas Gerais, Rondônia) and just reaching Paraguay (San Pedro) at 516(310-900) m elevation in wet areas in gallery forest, cerrado steeps, or brejo vegetation. (Henderson, A., A revision of Desmoncus (Arecaceae) in Phytotaxa 35. 2011)A

Discussion

  • Taxonomic notes:-A rather variable and heterogeneous species. Peduncular bracts are particularly difficult to score in this species, and subepidermal fibers are difficult to see in fruiting specimens.
    Subspecific variation:-Some specimens (e.g., Coradin 7331, Lindman 3273, Macedo 705, Pereira- Silva 4766, 4648) have slender inflorescences in which there is some adnation of the rachillae, and they occur at lower elevations. However, these specimens do not have a discrete range and are mixed with others. Other specimens (Archer 75, Ferreira 518, Hassler 11293, Mendes 251, Schinini 29368) have larger leaves and inflorescences. They come from the western margins of the range, near the Pantanal, where D. horridus subsp. prostratus occurs. There seems a possibility that there are either two different taxa here, or hybrids with other species, or both, but many more specimens are needed to decide the matter. (Henderson, A., A revision of Desmoncus (Arecaceae) in Phytotaxa 35. 2011)A

Description

  • Plants 4.6(1.0-10.0) m tall; stems 1.3(0.9-1.9) cm diameter, clustered. Leaf petioles 3.4(1.0-6.0) cm long; rachises 47.9(17.0-77.0) cm long, 5.7(4.2-7.5) mm wide, the spines usually <1 cm long, mostly abaxial, recurved with markedly swollen bases; pinnae 9(7-13) 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 14.0(5.5-24.0) cm long, 2.3(1.4-3.0) cm wide; cirri well-developed, with acanthophylls, with few spines abaxially, mostly on proximal part only, 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, closely spaced and spirally arranged rachillae, each rachilla not or rarely adnate to the rachis, subtended by an acute bracteole and with a well-developed axillary pulvinus; peduncles 2.4(1.0-5.4) mm wide; peduncular bracts 26.3(20.5-33.0) cm long, broad, the surfaces ribbed or ridged, brown tomentose or glabrous, sparsely to moderately covered with short, straight or sinuous, briefly swollen-based, diagonally or vertically oriented spines, these flattened or triangular in crosssection, whitish-brown proximally, black or brown distally, with tomentose margins; rachillae 11(10-16), glabrous or scarcely tomentose initially; proximal rachillae 6.0(3.5-10.5) cm long, 0.9(0.6-1.2) mm wide; stamens 6; fruits 12.3(10.9-13.9) mm long, 8.0(7.0-9.4) 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