Gayana Bot. 65(1): 115-118, 2008. Comunicación breve

COMUNICACION BREVE

OXALIS NOVEMFOLIALATA, A NEW SPECIES OF OXALIS SECT. CARNOSAE ENDEMIC TO THE ATACAMA DESERT OF NORTHERN CHILE

OXALIS NOVEMFOLIOLATA, UNA NUEVA ESPECIE DE OXALIS SECT. CARNOSAE ENDEMICA DEL DESIERTO DE ATACAMA, CHILE

Christoph Heibl^1,3 & Clodomiro Marticorena²

¹ Institut für Systematische Botanik, Fakultät für Biologie, Ludwig-Maximilians-Universität München, Menzinger Straße 67, 80638 München, Germany;
² Departamento de Botánica, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile. heibl@lmu.de

Resumen

Se describe Oxalis novemfoliolata Heibl & Martic. del desierto de Atacama, Chile. Hasta ahora ha sido encontrada solamente en Falda Verde cerca de Chañaral. Se distingue de las demás especies halladas en el territorio chileno por sus hojas en su mayoría 9-folioladas. Tanto la morfología del cáliz, forma de vida y suculencia, así como los marcadores moleculares, la agrupan a la sección Carnosae.

Oxalis L. comprises about 490 species (Lourteig 2000). It reaches major diversity in southern Africa (Salter 1944) and South America (Lourteig 1994, 2000) especially in arid desert and mountain environments. Members of section Carnosae Reiche are typical components of the flora of the subtropical desert belt along the South American Pacific coast and their diversity is centered in the Atacama coastal desert between 24°S and 30°S with about sixteen endemic species (Lourteig 2000, Heibl 2005).

During fieldwork in the Atacama Desert in 2004 and 2005, a new species belonging to Oxalis sect. Carnosae was found. The new species is here described, illustrated and compared to other species of Oxalis sect. Carnosae.

Oxalis novemfoliolata Heibl & Martic., sp. nov.

TYPE: CHILE, Región de Atacama, Provincia de Chañaral, south-facing, steep debris-covered slopes of Falda Verde. Sparsely covered with Heliotropium, Oxalis gigantea and Euphorbia lactiflua, 26° 17.67´ S, 70° 37.74´ W, 100 m, 21.10.2005, C. Heibl 02-022 (holotype: CONC; isotypes: M, SGO) (Fig. 1, 2).

A specie affini (Oxalis ornithopus Phil.) differt foliis 9-foliolatis vel raro 12-foliolatis, non 3-foliolatis. Foliola ad 7-15 mm longa et 1-4 mm lata, anguste cuneata, non linearia vel peranguste elliptica.

Perennial subshrub. Elongation of internodes very much reduced and stem therefore ± short (in the range of mm to cm, depending on age of plant), about 6 mm ø, a little bit fleshy, covered by sclerified, pubescent remains of stipules and leaf bases; leaves apically crowded together. Taproot fleshy, sometimes ramified, forming one or few ovoid to conical root tuber(s) right at the stem base and sharply separated from the fibrous roots below. Leaves 9-foliolate, seldom 12-foliolate, very short-lived, therefore often less than nine leaflets present or leaves have completely vanished at the time of anthesis. Petioles up to 8 cm long, fleshy, glabrous. Leaflets 7-15 x 1-4 mm, narrowly oblanceolate to narrowly cuneate, apex rounded to retuse, base cuneate; upper leaflet surface glaucous or waxy-shining, glabrous; lower leaflet surface colliculate, sparsely pubescent at base of midvein with single, nonglandular hairs, 1-1.5 mm long. Inflorescence a dichasial cyme, each of the two partial inflorescences is a cincinnus (= non-circinate scorpiod cyme; see Buys & Hilger, 2003), internodes of cincinni well developed, laxiflorous, but sometimes internodes of cincinni contracted, giving an umbel-like appearance to inflorescence. Peduncle up to 12 cm long, fleshy, glabrous. Pedicel 5-8 mm long, glabrous. Bracts ± 3 mm long, narrowly elliptic, apex acute, margin pubescent with short, single, nonglandular hairs, 0.4-0.6 mm long.

Figure 1. Oxalis novemfoliolata Heibl & Martic., photo taken at the type locality during the 2005 field trip (Photography by C.Heibl).

Figura 1. Oxalis novemfoliolata Heibl & Martic., fotografía tomada en la localidad tipo durante la campaña de 2005 (Fotografía de C. Heibl).

Figure 2. Oxalis novemfoliolata Heibl & Martic. (a) habit, (b) leaflet, (c) sepals, and (d) flower after removal of petals and sepals. (a) drawn after a photo taken in situ of an individual which showed stunted growth due to water stress. (b)-(d) drawn after a fully-developed individual (C. Heibl 01-078) from the Munich greenhouses. Note especially the differently shaped sepals in both cases. Note also that the internodes of cincinni can be much more developed than shown in (a) (see also text).

Figura 2. Oxalis novemfoliolata Heibl & Martic. (a) hábito, (b) folíolo, (c) sépalos y (d) flor después de remover el perianto. (a) dibujo según una foto tomada in situ de un individuo poco desarrollado debido a estrés hídrico. (b)-(d) dibujo de un individuo bien desarrollado (C. Heibl 01-078) de los invernaderos de la Universidad de Munich. Nótese la diferencias de la forma de los sépalos en ambos casos. Los entrenudos de los cincinos pueden estar mucho más desarrollados de lo que se muestra en el dibujo (a) (ver también texto).

Calyx fleshy, glaucous, with reddish sepal margins, glabrous, asymmetric: two outer sepals 6-7 x 3-4 mm broad, lanceolate to slightly hastate, apex obtuse and two inner sepals 6-7 x 1.5-2 mm broad, narrowly oblong, apex truncate to retuse, as well as a fifth sepal that is intermediate and can be described as being longitudinally split in two halves, one resembling the outer sepals and the other the inner sepals. Corolla campanulate, ± 30 mm diameter. Petals 5, connate at their base (± 4 mm), convolute, broadly spathulate, apex obtuse to subtruncate, lemon-yellow with purple outer margin on adaxial surface. Position and morphology of androecium and gynoecium vary accordingly to the tristylous condition of flowers: longs, mids, and shorts. Stamens 10, diadelphous. Filaments glanduliferous when in long and mid position, glabrous when in short position. Anthers dorsifixed, opening by longitudinal splits. Carpels 5, ovary superior, connate, forming a pistil, glabrous. Styles terminal, distinct, glanduliferous when in long or mid position, glabrous when in short position, Stigmata distinct, club-shaped, papilliferous. Capsule 6 x 2 mm, cylindrical, loculicidal dehiscence. Seeds ± 1 mm, ovoid, transversally striated, reddish brown. Chromosome number unknown.

MATERIAL STUDIED

Chile: Region of Atacama, Prov. Chañaral, Falda Verde, i.e. slopes of Cerro Chañaral 4-5 km N of Chañaral, 100-450 m, 05.X.1997, Eggli 2885 (B, CONC, SGO, ZSS); Prov. Chañaral, South-facing, stony slopes west of Falda Verde, 100-450 m, 12.XII.2004, Heibl 01-078 (M); Prov. Chañaral, South-facing, stony slopes west of Falda Verde, 100 m, 21.X.2005, Heibl 02-022 (CONC, SGO, M); Prov. Chañaral, Falda Verde, 450 m, 05.XI.2005, Schulz FV46 (ULS).

Taxonomic position

Morphologically, O. novemfoliolata clearly belongs to Oxalis section Carnosae which is characterized by asymmetrical calyces with the outer sepals being deltoid, rhomboid, lanceolate or hastate, rarely ovate and the inner sepals being narrowly oblong (Lourteig 2000; Heibl et al. in prep.). In addition to calyx morphology, also growth form and succulence of leaves, peduncles, and sepals also suggest affiliation to section Carnosae. Molecular markers strongly support these findings. A non-coding cp DNA data set consisting of psbA-trnH spacer, trnL intron and trnL-trnF spacer confirmed the monophyly of section Carnosae including O. novemfoliolata (Heibl 2005, Heibl & Renner in prep.). Within the section, however, O. novemfoliolata is unmistakably distinguished from the other species by its 9-foliolate (or seldom 12-foliolate) leaves and its narrowly cuneate leaflet shape.

Distribution, habitat, and conservation status

To date O. novemfoliolata is only known from one locality, locally known as `Falda Verde', e.g. the slopes between Cerro Chañaral and Cerro Falda Verde north of Chañaral (Fig. 3). At this locality it has been collected four times (Accession numbers: U. Eggli 2885, C. Heibl 01-078, C. Heibl 02-022, N. Schulz FV46).

Figure 3. Currently known distribution of Oxalis novemfoliolata Heibl & Martic. It has only been collected in a small area (¾in the left panel) on the southern slopes between Cerro Chañaral and Cerro Falda Verde at an altitude between 100 and 380 m.

Figura 3. Distribución actualmente conocida de Oxalis novemfoliolata Heibl & Martic. Solamente ha sido recolectada en un área pequeña (¾a la izquierda en el mapa) sobre las laderas de exposición sur entre Cerro Chañaral y Cerro Falda Verde a una altitud ente 100 y 380 m.

The species is found from about 100 to 380 m altitude on the steep, south-facing, and debris-covered slopes of Falda Verde between coarse gravel and a sparse, xerophytic vegetation cover which is dominated by shrubby perennials such as Eulychnia iquiquensis K.Schum. (Britton & Rose), Heliotropium pycnophyllum Phil., Oxalis gigantea Barnéoud, and Euphorbia lactiflua Phil. This vegetation corresponds to the ecotone between `Mediterranean Coastal Desert Shrub of Gypothamnium pinifolium Phil. and Heliotropium pycnophyllum Phil.' and `Mediterranean Coastal Desert Shrub of Euphorbia lactiflua Phil. and Eulychnia saint-pieana F.Ritter (= E. iquiquensis (K.Schum.) Britton & Rose sensu Hoffmann & Walter 2004)' according to Luebert & Pliskoff (2006). The climate under which these plant communities grow is characterized by the compensatory effect of the nearby Pacific ocean and frequently occurring coastal fogs on the otherwise hyperarid desert climate with high solar radiation and erratic rainfalls.

Currently, there seems to be no direct threat to the survival of O. novemfoliolata. Human activities in the past such as road construction, installation of antenna towers and fog collectors have concentrated mainly on the coastal plains below and the summit region above the slopes where it grows. Nevertheless the species is inherently vulnerable due to its extremely small distributional range (as known to date) and should be explicitly considered in land managing plans concerning this area.

ACKNOWLEDGEMENTS

The first author would like to thank the Deutsche Kakteengesellschaft e.V. (DKG) for financial support for the fieldwork in 2004, the Freunde des Botanischen Gartens München for a travel grant received for the fieldwork in 2005, Jürke Grau for help concerning the illustrations, and Susanne Renner for comments on the manuscript.

BIBLIOGRAPHY

Buys, M. H. & H. H. Hilger. 2003. Boraginaceae cymes are exclusively scorpioid and not helicoid. Taxon 52: 719-724.         [ Links ]

Heibl, C. 2005. Studies on the systematics, evolution, and biogeography of Oxalis sections Caesiae, Carnosae, and Giganteae, endemic to the Atacama desert of northern Chile. Diploma thesis, Department of Biology, University of Munich, Germany. 110 pp.         [ Links ]

Hoffmann, A. E. & H. E. Walter. 2004. Cactáceas en la flora silvestre de Chile. Segunda edición. Ediciones Fundación Claudio Gay, Santiago de Chile. 307 pp.         [ Links ]

Lourteig, A. 1994. Oxalis L. Subgéneros Thamnoxys (Endl.) Reiche emed. Lourt. Bradea 7(1): 1-199.         [ Links ]

Lourteig, A. 2000. Oxalis L. Subgéneros Monoxalis (Small) Lourt., Oxalis y Trifidus Lourt. Bradea 7(2): 201-629.         [ Links ]

Luebert, F. And P. Pliscoff. 2006. Sinopsis bioclimática y vegetacional de Chile. Editorial Universitaria, Santiago. 316 pp.         [ Links ]

Salter, T.M. 1944. The genus Oxalis in South Africa: a taxonomic revision. Journal of South African Botany, Supplement 1: 1-355.         [ Links ]

Recibido: 23.01.08
Aceptado: 10.03.08