Desmoncus polyacanthos
Desmoncus (dehs-MON-koohs) polyacanthos (poh-lee-AH-kahn-tohs) | |||||||
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![]() Brazil. Photo by Dr. Andrew J. Henderson/Palmweb. | |||||||
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Contents
Habitat and Distribution
Desmoncus polyacanthos is found in Bolivia, Brazil North, Brazil Northeast, Brazil Southeast, Brazil West-Central, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, Trinidad-Tobago, and Venezuela. From 10°37'N-21°31'S and 35°09'-78°38'W in Trinidad, Venezuela, the Guianas, Brazil (including the Atlantic Coastal Forest), Colombia, Ecuador, Peru, and Bolivia at 205(0-1000) m elevation in a variety of habitats including lowland rainforest on terra firme, flooded forest, campina, restinga, or scrub forest near the sea. Read (1979) also included the Lesser Antillean island of St. Vincent in the distribution of this species, but only one, sterile specimen from there has been seen. There is another specimen at P labelled "Martinique" but without more precise locality. (Henderson, A. 2011)/Palmweb.Description
Subcanopy reaching liana (climbing). Stems solitary or clustered.
Palm 7.2 (1.0-37.0) m tall; stems 1.4 (0.5-2.9) cm in diameter, clustered. Leaf petioles 3.2 (0.5-13.5) cm long; rachises 63.8 (25.0-173.0) cm long, 5.2 (1.8-12.9) mm wide, the spines usually <1 cm long, mostly abaxial, recurved with markedly swollen bases; pinnae 8 (4-15) 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 15.8 (3.3-40.0) cm long, 2.7 (0.3-5.8) cm wide; cirri well-developed, with acanthophylls, cirri with spines abaxially mostly on proximal part only, without intermediate acanthophylls present, with a wide gap between pinnae and acanthophylls. Inflorescences with the rachis thicker than the few, closely spaced and spirally arranged rachillae, each rachilla subtended by an acute bracteole and with an axillary pulvinus; peduncles 3.5 (1.6-12.4) mm wide; peduncular bracts 26.3 (16.5-34.0) cm long, broad, sparsely to densely covered with short, markedly swollen-based, diagonally oriented spines, these triangular in cross-section, whitish-brown proximally, brown distally, with tomentose margins, rarely spines few or absent; rachillae 15 (5-37), glabrous or scarcely tomentose initially; proximal rachillae 7.4 (3.3-13.0) cm long, 1.1 (0.6-2.0) mm wide; stamens 5-6; fruits 16.4 (11.2-23.5) mm long, 11.9 (7.9-17.9) mm wide, the surfaces smooth, without any apparent subepidermal 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 apices, the pores lateral, not equidistant, the sterile pores closer latitudinally (Henderson, A. 2011)/Palmweb. Editing by edric.
The species is recognised by its recurved, hook-like spines on the leaf rachis and cirrhus, and entire, spiny leaf sheath.
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Taxonomic notes:-Desmoncus polyacanthos Martius was emended by Drude (1881) and excluded by Burret (1934). However there seems no reason for these designations. Martius's (1823-1837) description and illustration, based on an extant type collected by Martius himself, perfectly represent this widespread species. Subspecific variation:-There is geographic disjunction and specimens occur in two regions-the Atlantic Coastal Forest of Brazil, and all other areas. Specimens from the Atlantic Coastal Forest differ significantly from others from Brazil in only three variables (rachis length, number of pinnae, rachilla width)(t-test, P <0.05). Only one species is therefore recognized, without any subspecific division. Nevertheless, Desmoncus polyacanthos is, after D. mitis, the second most variable species in the genus, and is by far the most widespread. Starting from the north, specimens from the Coastal Range in Venezuela (mirandanus morphotype) have larger inflorescences with more rachillae (mean of 19 versus 12) than other specimens from Venezuela. Specimens from western (Apure, Barinas, Zulia) and southern parts of Venezuela (Amazonas, Bolívar, Delta Amacuro) are rather uniform (ulei morphotype). Specimens from Trinidad and the Guianas are also rather uniform, apart from the usual variation in size and spininess, and are considered part of the ulei morphotype. Along the coast of the Guianas, D. polyacanthos occurs slightly more inland than the sympatric, coastal D. horridus subsp. horridus. Specimens from Brazil (Amazonas, Maranhão, Pará, Roraima) are rather uniform (ulei morphotype), with some exceptions. Two specimens (Balick 951, Cavalcante 1611) from near the Rio Tapajós, Pará, have exceptionally wide pinnae. A few specimens from Amazonas are unusual. The type of D. ulei (Ule 5388), from the Rio Negro near Manaus, is atypical in having straight spines on the pinnae veins. A few other specimens have these kind of spines, and others have short, recurved spines on the pinnae veins. In western Amazonas two specimens (Mori 9128, Pardini 39) are much larger than the others and are referred to the large morphotype (see below). Some specimens from Amazonas and Pará may be hybrids and are from campinas near areas where both D. polyacanthos and D. pumilus occur. One (Loureiro s.n.) from north of Presidente Figueiredo has narrow pinnae and fruits with Y-shaped fibers. A second (Scariot 621), from the same general area, has more usual pinnae but also has fruits with Y-shaped fibers. A third (Henderson 300) from near Manicoré has narrow pinnae and an elongate inflorescence. A group of specimens from near Tucurui in Pará may also be hybrids. They are reported to occur in low forest on white sand and are from a highly disturbed area near the Tucurui Dam. Two (Plowman 9742, 9577) have very slender stems, narrow pinnae, and fruits with Y-shaped fibers. Other specimens from nearby (Miranda 470, Plowman 9881) are somewhat larger and have smooth fruit surfaces without any apparent subepidermal fibers. There is extreme variation amongst specimens from the western Amazon region and subAndean foothills in Colombia, Ecuador, Peru, and Brazil. Much of this appears to be regional, i.e., specimens from the same region are similar and differ from those of other regions. These regions are separate from one another, but the gaps between them are likely to be artifacts of insufficient collecting. In most cases there are too few specimens to test for differences amongst regions. In general, western Amazon specimens are larger than the ulei morphotype, sometimes markedly so. Most are referred to as the large morphotype, although there is great variation amongst them. There is a curious absence of specimens from the Colombian Amazon, especially the central part. Specimens from Meta and Cudinamarca in the northwestern part are included in the ulei morphotype, and another (Rudas 2297) from the southeastern part (Amazonas) in the large morphotype. In Ecuador specimens are variable and two (Balslev 62438, Croat 88912) come from unusually high elevations (1000-1121 m). Other specimens from lower elevations are smaller. The two easternmost specimens in Ecuador have the widest pinnae, similar to another specimen (Gentry 22007) from adjacent Peru on the border with Ecuador which has unusually wide, ovate pinnae. All these are referred to as the large morphotype. In central and eastern Loreto, Peru, especially in the Iquitos region, most specimens are large with mostly ovate, rarely lanceolate pinnae, sparsely and coarsely spiny peduncular bracts, and large fruits. They are referred to as the large morphotype. However, there are a few specimens that are smaller and are referred to the ulei morphotype. One specimen (Vásquez 2300) has spinulose pinnae bases and may be a hybrid with Desmoncus mitis. In southern Loreto, the few specimens have ovate pinnae and densely spiny peduncular bracts and are referred to the ulei morphotype. In northwestern Peru (Amazonas) and just reaching extreme southern Ecuador (Zamora-Chinchipe), specimens are large with ovate pinnae, densely spiny peduncular bracts, and large fruits. They are referred to as the amazonas morphotype. In central Peru (San Martín) specimens are extremely variable. A single specimen from southern San Martín (Schunke 6927) is larger, with densely spiny sheaths and long, almost linear pinnae (sanmartin morphotype). A second specimen from the northern part of the department (Williams 6661) is completely different, with smaller, ovate pinnae and a finely spiny peduncular bract (ulei morphotype). In south-central Peru (Pasco) there are two specimens (Henderson 3009, Smith 3791) which are considerably larger than others and have large stems, long, lanceolate pinnae, and large inflorescences with densely spiny peduncular bracts (pasco morphotype). A specimen from Ucayali (Gentry 25466) is similar, but another from adjacent Junín (Macbride 5470) has more ovate pinnae and is referred to the large morphotype. In western Acre, Brazil, and adjacent Peru (Ucayali) specimens are of the large morphotype. One specimen (Henderson 1675) from western Acre on the border with Amazonas is of the ulei morphotype. Five specimens from eastern Acre (Coêlho 28, Daly 9387, 11986, Figueiredo 342, 615) resemble those of the ulei morphotype except for their pinnae with spinulose bases. They may represent hybrids with the sympatric D. mitis subsp. ecirratus. In Madre de Dios, Peru and western Bolivia specimens are all of ulei morphotype, although there is much variation in fruit size. Specimens from the Atlantic Coastal Forest of Brazil (polyacanthos morphotype) occur in two areas, with northern outliers in Ceará, Alagoas, and Pernambuco. There are too few specimens from there to test for differences between these areas. Along the Atlantic coast, D. polyacanthos occurs slightly more inland than the sympatric D. orthacanthos. (Henderson, A. 2011)/Palmweb. |
Culture
Sheltered, moist but well drained postion. Tropical.
Comments and Curiosities
Uses: Stems are collected by country people, on demand from the manufacturerin the city. The plant is cut at ground level and the sheathing leaf bases are strippedaway. The stem is then rolled up, and taken to the city. The uses of Desmoncus stems reported here were exclusively based on split stems called skeins. The actual weaving and basket making were all done in cottage industries, in private homes, back yards, garages, etc. Armchairs with seats woven of these materials. seed is buffed to make necklaces. fibers are used to make rope.
- IMAGE GALLERY
External Links
References
Phonetic spelling of Latin names by edric.
Special thanks to Geoff Stein, (Palmbob) for his hundreds of photos.
Special thanks to Palmweb.org, Dr. John Dransfield, Dr. Bill Baker & team, for their volumes of information and photos.
Glossary of Palm Terms; Based on the glossary in Dransfield, J., N.W. Uhl, C.B. Asmussen-Lange, W.J. Baker, M.M. Harley & C.E. Lewis. 2008. Genera Palmarum - Evolution and Classification of the Palms. Royal Botanic Gardens, Kew. All images copyright of the artists and photographers (see images for credits).
Henderson, A. 2011. A revision of Desmoncus (Arecaceae).
Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.