Xyris labatii Rakoton., Callm. & Phillipson

Rakotonirina, Nivo, Callmander, Martin W., Phillipson, Peter B. & Lock, J. Michael, 2014, Two new species of Xyris L. (Xyridaceae) endemic to Madagascar with a key to the Malagasy species, Candollea 69 (2), pp. 171-178: 174-175

publication ID

http://doi.org/ 10.15553/c2014v692a9

persistent identifier

http://treatment.plazi.org/id/03F987B6-FFDE-FF94-FFA3-10C2FEA06918

treatment provided by

Carolina

scientific name

Xyris labatii Rakoton., Callm. & Phillipson
status

 

Xyris labatii Rakoton., Callm. & Phillipson   , spec. nova ( Fig. 3 View Fig , 4 View Fig ).

Typus: MADAGASCAR. Prov. Antananarivo: Ambatofinandrahana, massif de l’Itremo , Atsirakambiaty , 20°35’22”S 46°34’01”E, 1680 m, 27.III.1999, fl., Labat 3050 (holo-: P [ P00160157]!; GoogleMaps   iso-: G [ G00341191]!, K, MO!, TAN! GoogleMaps   ).

Haec species a congeneris madagascariensibus caule e base tumida orto, foliis filiformibus, caulibus scapisque spiraliter tortis atque seminibus obovoideis distinguitur.

Clumped perennial herb, tufted (10-) 20-50 cm. Stem spirally twisted, from the bulbous base to the shoot. Leaves up to 23 × 0.1 cm; sheaths (0.4-) 1-5 cm long, ridged, ligule c. 1 mm, slightly acute, brown-hyaline; blades filiform and coriaceous, strigillose, symmetric and aristate at the apex, margins thickened. Scapes up to (1-)8-28 × 0.1 cm, terete. Inflorescences ellipsoid, c. 0.3-0.6 × (3-) 0.5-0.6 cm, red-brown. Sterile bracts, 2-6, obovate, glossy brown, rounded to acute at the apex; fertile bracts ovate-elliptic c. 0.6 × 0.3 cm, apex acute, concave, smooth glossy brown, hyaline towards the margins, sometimes erose. Flower with lateral sepals c. 1.3 × 0.4 cm, slightly curved, keeled, hyaline and darker on the keel, smooth. Petals obovate, c. 0.1 × 0.08 cm yellow. Stamens 3, anther sessile, linear-shaped, c. 1.2 × 0.2 mm, epipetalous. Ovary obovate c. 3 × 1.2 mm, brown. Style 3-branched, 1.2 mm long; stigma twisted, 2.4 mm long. Fruits obovate, 2 × 1.5 mm, glabrous, with a longitudinal dark-brown dehiscence groove. Seeds obovoid, 0.3 × 0.2 mm, dark brown

Distribution and ecology. – Xyris labatii   is known from the central highlands of Madagascar, in the Amoron’i Mania, Vakinankaratra and Haute Matsiatra regions. It grows on rocky areas, often on quartzite from 1200 to 2500 m ( Fig. 2 View Fig ).

Etymology. – The species epithet honours our friend and colleague, Jean-Noël Labat (1959-2011) who disappeared too soon. Jean-Noël collected the type specimen and as is often the case, he made a useful photograph to accompany his excellent collection.

Notes. – Xyris labatii   can be recognized by its bulbous stem bases and its twisted leaves and scapes. It is similar to X. humilis   , which also occurs in the central highlands of Madagascar, but the new species can be distinguished by its filiform leaves (vs. very narrowly linear in X. humilis   ) (8-23 × 0.1 cm vs. 3-5 × 0.1-0.2 cm).

Conservation status. – With an EOO of 12,460 km ², and an AOO of 153 km ² and eleven subpopulations, two of which are in the protected area network (Andringitra), X labatii   is assigned a preliminary status of “Least Concern” (LC) following IUCN Red List Categories and Criteria ( IUCN, 2012)

Paratypi. – MADAGASCAR. Prov. Antananarivo: Mont Ibity , c. 27 km SW of Antsirabe, 20°05’24”S 47°00’23”E, 1840-1890 m, 15.III.2004, Almeda 8706 ( CAS, TAN); GoogleMaps   Antsirabe, Beapombo, à 400 m avant d’arriver au sommet d’Ibity, 20°04’58”S 47°00’37”E, 2170 m, 5.II.2003, Andriamihajarivo 103 ( MO, P [ P00853040], TAN); GoogleMaps   ibid. loc., 20°10’S 47°03’E, 1300-1800 m, 6.III.1985, Dorr & al. 3853 ( MO, P [ P01641000]); GoogleMaps   ibid. loc., 20°07’00”S 47°01’00”E, 24.XII.1965, Peltier 2127 ( P [ P01640947]); GoogleMaps   Mahasoa à Ambohimasina, Betafo , [19°50’S 46°51’E], III.1976, A. Rakotozafy 1736 ( TAN); GoogleMaps   Hauts-plateaux, env. à 15 km à l’W de Arivonimamo (entre Arivonimamo et Soamahamanina, 60 km à l’W de Antananarivo), 18°54’43”S 47°05’21”E, 1260 m, 23.I.2000, Raynal-Roques & Jérémie 24816 ( G, K, MO, P [ P00853043], TAN, WAG); GoogleMaps   ibid. loc, 20°05’33”S 47°00’14”E, 2080 m, 16.II.2003, Schatz & al. 4075 ( MO); GoogleMaps   ibid. loc., 20°04’10”S 47°00’16”E, 1700 m, 17.II.2003, Schatz & al. 4130 ( MO, P, TAN). GoogleMaps   Prov. Fianarantsoa: Sommet très rocheux (quartzitique) à l’E d’Antsirakambiaty , à l’W d’Ambatoandrano, 20°34’39”S 46°34’26”E, 1681 m, 18.IV.2003, Andriamihajarivo 179 ( MO, P, TAN); GoogleMaps   10 km W of Ivato on route #35, [20°34’30”S 46°37’30”E], 1500-1685 m, 27.I.1975, Croat 29532 ( MO, P [ P01640906], TAN); GoogleMaps   Vicinity of col de Itremo , [20°34’30”S 46°37’30”E], 1500-1685 m, 27.I.1975, Croat 29830 ( MO, TAN); GoogleMaps   Env. d’Ambatofinandrahana , [20°33’S 46°48’E], 1600-1800 m, 19.II.1938, Decary 12993 ( P [ P00853042]) GoogleMaps   ; ibid. loc., Decary 13090 ( P [ P00853041]) GoogleMaps   ; Mt Boby , [22°11’S 46°53’E], 20. III.1945, Homolle 1209 ( P [ P01924015]) GoogleMaps   ; ibid. loc., Homolle 1201 ( P [ P01924014], TAN) GoogleMaps   ; Massif de l’Andringitra ( Iratsy ), vallées de la Riambava et de l’Antsifotra et montagnes environnante, [22°12’S 46°55’E], 2000- 2500 m, 27. XI.1924, Humbert 3890 ( P [ P01640921, P01640957]) GoogleMaps   ; Massif de l’Itremo , W of Ambatofinandrahana: Montagnes à l’W ( W Betsileo), [20°34’30”S 46°37’30”E], 1500-1700 m, 17-22. I. & 18- 22.IV.1955, Humbert 28325 ( P [ P019524021]) GoogleMaps   ; ibid. loc., Humbert 29893 ( P [ P01640936]) GoogleMaps   ; ibid. loc., Humbert 29936 ( G, K, MO, P [ P00730639, P00730641], TAN, WAG) GoogleMaps   ; Route Ambositra à Ambatofinandrahana sur rocher après l’embranchement d’Ivato, 20°33’S 46°48’E, III.1960, Keraudren 158 ( P [ P01640896]) GoogleMaps   ; Itremo mountain , c. 1 km below the highest point of the road, 20°36’S 46°35’E, 1600 m, fl., 17. III.1995, Lye, Arnstein & Ranaivojaona 20894 ( TAN) GoogleMaps   ; Itremo massif, W of Ambatofinandrahana, along road to Col d’Itremo, ca. 2 km before ( NE of) bridge over Ambalarangolana creek, 20°33’58”S 46°35’35”E, 1450 m, 10.XI.2002, Lowry & al. 5914 ( MO, TAN) GoogleMaps   ; ibid. loc., 20°40’S 46°35’E, 1600 m, fl., 23. III.1971, Mabberley 780 ( K, TAN) GoogleMaps   ; ibid. loc., [20°37’S 47°12’E], 24.XII.1965, Peltier 5612 ( P [ P0164927]) GoogleMaps   ; ibid. loc., 20°36’45”S 46°35’05”E, 1650 m, 14. III.1992, Phillipson, Clement & Rafamantananantsoa 3889 ( MO, TAN) GoogleMaps   ; ibid. loc., inselberg à 11,7 km d’Ivato vers la route d’Ambatofinandrahana, et c. 4 km avant le village d’Anjoman’ Ankona, 20°39’45”S 47°07’42”E, 1500 m, fl., 24. III.2010, Rakotoarivelo & al. 330 ( MO, P, TAN) GoogleMaps   ; ibid. loc., about 6 km NW of Itremo , 20°33’35”S 46°34’55”E, 1333 m, 9.II.2009, Rakotoarisoa 628 ( K, MO, P, TAN) GoogleMaps   .

P

Museum National d' Histoire Naturelle, Paris (MNHN) - Vascular Plants

G

Conservatoire et Jardin botaniques de la Ville de Genève

K

Royal Botanic Gardens

MO

Missouri Botanical Garden

TAN

Parc de Tsimbazaza

CAS

California Academy of Sciences

A

Harvard University - Arnold Arboretum

WAG

Wageningen University

W

Naturhistorisches Museum Wien

I

"Alexandru Ioan Cuza" University

NE

University of New England

Kingdom

Plantae

Phylum

Tracheophyta

Class

Liliopsida

Order

Poales

Family

Xyridaceae

Genus

Xyris