Roscheria H.Wendl. ex Balf.f., Fl. Mauritius : 386 (1877)

Primary tabs

http://media.e-taxonomy.eu/palmae/photos/palm_tc_179837_5.jpg

Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)
Seychellespresent (World Checklist of Arecaceae)B
Monotypic, confined to Mahé and Silhouette Islands in the Seychelles. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Discussion

  • Roscheria is the only member of the Verschaffeltiinae to possess a crownshaft. Nevertheless, the inflorescences are interfoliar, at least at anthesis. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Diagnosis

  • Small or moderate solitary spiny palm endemic to Seychelles, with a conspicuous crownshaft and with leaves divided into few broad segments with praemorse tips; inflorescences have long peduncles and very small flowers. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Biology And Ecology

  • An undergrowth palm of mountain rain forest, very rarely found below 500 m altitude; at ca. 750 m it can form pure stands on very steep slopes in the undergrowth of Northia forest. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Common Name

  • Latanier hauban. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Etymology

  • Commemorates Dr Albrecht Roscher (1836–1860), German explorer who followed close on Burton, Speke and Grant in exploring East Africa. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Uses

  • Uses not recorded, apart from being a prized ornamental. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Description

  • Small or moderate, solitary, spiny when young, sparsely armed at maturity, pleonanthic, monoecious palm. Stem erect, becoming bare, conspicuously ringed with leaf scars, the juvenile bearing rings of black spines, at maturity unarmed or with very few, scattered, weak spines, the stem base sometimes with aerial roots. Leaves irregularly pinnate, neatly abscising; sheaths tubular, forming a well-defined crownshaft, covered in scattered brown scales and armed with scattered, short, black spines, spines much more densely near the base of the petiole; petiole adaxially deeply channelled, abaxially rounded, densely armed along the margins near the base with short, easily detached, black spines; rachis unarmed, bearing scattered scales; blade entire, bifid in juveniles, at maturity irregularly divided into 1–several-fold leaflets, those with single ribs acuminate, those with several ribs truncate, praemorse, adaxially glabrous, abaxially bearing abundant minute, dot-like scales and conspicuous ramenta along the major ribs, transverse veinlets obscure. Inflorescences solitary, interfoliar at first, becoming infrafoliar after leaf fall, copiously branching to 3, very rarely to 4 orders proximally, to fewer orders distally; peduncle elongate, crescentic in cross-section, winged at the base; prophyll inserted some distance from the base, membranous to coriaceous, tubular, persistent, flattened, 2-keeled, briefly split at the tip, unarmed, bearing scatteredsmall scales; peduncular bract inserted some distance above theprophyll, usually much exceeding it, very sparsely scaly, tubular at first,later splitting along much of its length and expanding, eventuallyfalling; rachis usually shorter than the peduncle; rachis bracts all minute,triangular, very inconspicuous; branches of all orders with a short tolong portion free of branches or flowers, all axes scaly; first-orderbranches subdistichous, the proximal longer than the distal; rachillaeslender, rather short, flexuous, bearing spirally arranged, minute bractssubtending triads in the middle portion and paired or solitary staminateflowers distally, the flowers not at all sunken. Staminate flowers verysmall, globular in bud; sepals 3, ± distinct, imbricate, broad, triangular,± keeled; petals 3, distinct, valvate, more than twice as long as thesepals, broad, triangular; stamens 6, filaments connate basally to form alow ring, the distinct portions short, broad, triangular, anthers verysmall, rounded, medifixed, ± versatile, latrorse; pistillode relativelylarge, truncate, 3-angled. Pollen ellipsoidal asymmetric; aperture a distalsulcus; ectexine tectate, rugulate-reticulate with finely ridged muri,aperture margin similar; infratectum columellate; longest axis 28–33 µm [1/1]. Pistillate flowers larger than the staminate; sepals 3, distinct, thick, imbricate, broad, rounded, the margins irregularly splitting; petals 3, distinct, broad, triangular, the tips briefly valvate, otherwise imbricate; staminodes 6, tooth-like, ± united basally; gynoecium asymmetrical, ovoid, unilocular, uniovulate, stigma apical, 3-lobed, ovule laterally attached, form unknown. Fruit small, globular or ellipsoidal, red at maturity, perianth whorls persistent, stigmatic remains subbasal; epicarp smooth, mesocarp very thin, with a layer of anastomosing fibres and abundant raphides, endocarp relatively thick, bony, smooth, with basal operculum. Seed basally attached with rounded hilum, raphe branches sparse, anastomosing, endosperm deeply ruminate; embryo basal. Germination and eophyll not recorded. Cytology: 2n = 32. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Anatomy

  • Root (Seubert 1998a, 1998b) and fruit (Essig et al. 2001). (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Fossil record

  • Reticulate trichotomosulcate pollen from the Lower Eocene of Saudi Arabia is compared erroneously with Roscheria melanochaetes pollen (Srivastava and Binda 1991). (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Relationships

  • Roscheria is resolved as sister to Verschaffeltia with high support (Lewis and Doyle 2002, Lewis 2002, Loo et al. 2006, Norup et al. 2006, Baker et al. in review, in prep.). (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Taxonomic accounts

  • Bailey (1942). (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Bibliography

A. J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008
B. World Checklist of Arecaceae