Polylepis incarum (Bitter) M.Kessler & Schmidt-Leb., Oranisms Diversity Evol. 6(1): 69. 2006.

Boza Espinoza, Tatiana Erika & Kessler, Michael, 2022, A monograph of the genus Polylepis (Rosaceae), PhytoKeys 203, pp. 1-274 : 1

29. Polylepis incarum (Bitter) M.Kessler & Schmidt-Leb., Oranisms Diversity Evol. 6(1): 69. 2006.

Figs 79 , 80

Polylepis besseri Hieron. subsp. incarum (Bitter) M.Kessler, Candollea 50(1): 157. 1995. Type. Based on Polylepis incarum Kunth subsp. Polylepis incarum Incarum Bitter.

Polylepis incana Kunth subsp. brachypoda Bitter, Bot. Jahrb. Syst. 45: 644. 1911. Type. Bolivia. Lago Titicaca, Isla del Sol, near Challa, Seler 148a (holotype: B destroyed).

Basionym.

Polylepis incana Kunth subsp. incarum Bitter, Bot. Jahrb. Syst. 45: 643. 1911.

Type.

Bolivia. Lago Titicaca, Isla del Sol near Challa, Seler 148 (holotype: B destroyed).

Neotype.

Bolivia. La Paz, Prov. Manco Capac, Isla del Sol, Yumani, 16°2'S, 69°8'W, 3980 m, 19 Feb 2005, I. Jiménez & G. Cory 2716 (neotype, designated by Kessler and Schmidt-Lebuhn 2006, pg. 6: LPB!; isoneotypes: AAU!, GOET!, MO!, NY!).

Description.

Trees 3-8 m tall. Leaves slightly congested at the branch tips, imparipinnate with one pair of leaflets, obtrullate in outline, 3.3-4.5(-5.1) × 2.8-4.0 cm; rachises densely tomentose, points of leaflet attachment with a tuft of long hairs; stipular sheaths apically acute with spurs, densely tomentose on the outer surfaces; leaflets broadly elliptic in outline, second pair from the terminal leaflet the largest, one of this pair (1.5-)2.2-3.6 × 0.7-1.3 cm; margin serrate with 8-11 teeth, apically acute, obtuse or slightly emarginate, basally unequally cordate to obtuse; upper leaflet surfaces glabrous; lower leaflet surfaces densely tomentose hairs 0.7-1.0 mm long, mixed with a dense layer of very short white pannose hairs. Inflorescences pendant, 5.1-7.5(-8.9) cm long, bearing 5-7 flowers; floral bracts 4.7-9.0 mm long, narrowly triangular, densely tomentose on the outer surface; rachises tomentose. Flowers 8.4-10.1 mm diam.; sepals 4, ovate, green, densely tomentose outside; stamens 15-21, anthers orbicular, with a dense tuft of straight white hairs on the upper half; styles fimbriate, 3.1-3.4 mm long. Fruits turbinate, with 2-5 flattened ridges with a series of spines, densely tomentose; 4.5-8.0 × 3.1-4.1 mm including spines. Tetraploid.

Distribution, habitat and ecology.

Polylepis incarum is distributed in the areas surrounding Lake Titicaca in Puno (Peru) and La Paz (Bolivia) (Fig. 92 ). It occurs as small, isolated patches in rocky places at 3250-4110 m elevation where it is usually planted. In Bolivia, there are only five remaining forests as well as isolated individuals or small groups of trees at various locations around Lake Titicaca ( Navarro et al. 2010) covering a total area of 45.12 ha ( Domic et al. 2017). The population structure of P. incarum shows drastic differences, ranging from 0.6 individuals/100 m2 to 71 individuals/100 m2 ( Domic et al. 2017). Patches of P. incarum forest in Bolivia host 58 species of plants, including Hieracium padcayense and Calceolaria bartsifolia , which are endemic to the country ( Hurtado et al. 2018).

Conservation status.

The EOO for Polylepis incarum is estimated as 20,736 km2, the AOO is assessed at 76 km2 and it is known from 12 locations. The species was categorized as EN (B2ab(i,ii,iii)) ( Arrázola et al. 2012) and, due to its reduced distribution range, it was reclassified as CR ( Domic et al. 2017) in Bolivia. Since the 70s, several reforestation campaigns have been carried out in the Bolivian Altiplano, which mostly promoted the use of exotic species ( Eucalyptus , Pinus and Cupressus ) over the P. incarum patches, due to the high demand for wood and rapid growth of these genera ( Liberman et al. 2015; Domic et al. 2017). At many of its locations, the species grows in habitats that are strongly affected by human activities including livestock grazing, logging and burning. In addition, there is indication of reduced reproduction due to pollen limitation and reproductive incompatibility ( López et al. 2021). We assess P. incarum as Critically Endangered (A1, B1a+B2a, C1+C2a).

Notes.

Polylepis incarum is morphological similar to P. pallidistigma with which it has been previously confused ( Mendoza and Cano 2012). Both species share the elliptic leaflet shape, unequally cordate bases of the leaflets and number of flowers per inflorescence. However, P. incarum has one pair of lateral leaflets, serrate leaflet margins, lower leaflet surfaces densely tomentose with hairs 0.7-1.0 mm long and mixed with a dense layer of very short pannose hairs and inflorescences 5.1-8.9 cm long, whereas P. pallidistigma has 1(-2) lateral leaflet pairs, crenate leaflet margin, a dense layer of very short pannose hairs and inflorescences 2.7-6.0 cm long. Polylepis incarum is also similar to P. subtusalbida . It differs from this species by having larger and broader leaflets ((1.5-)2.2-3.6 × 0.7-1.3 cm versus 0.9-1.6 × 0.4-0.6 cm), lower leaflet surface densely tomentose with hairs 0.7-1.0 mm long and mixed with a dense layer of very short pannose hairs (glabrous to sparsely tomentose hairs 0.5-1.2 mm long in P. subtusalbida ) and longer inflorescences (5.1-8.9 cm) with 5-7 flowers ( P. subtusalbida 1.8-3.7 cm, 3-4 flowers).

Specimens examined.

Bolivia. La Paz: Camacho, Puerto Acosta 6 kms. hacia La Paz , 3950 m, 06 April 1982, Beck 7689 (MO!). Copacabana , Lake Titicaca , pr. Ch’alla ( Isla del Sol ), s.d., Seler 148 (B). La Paz , Jardin Botanico La Paz , s.d., Kessler 12626 (GOET!). Manco Kapac , apróx. 5-10 min de la población de Copacabana , camino a Casani , comunidad Copacati , Ladera colindante Cerro Pumacato , 16°11'06"S, 069°04'43"W, 3934 m, 17 October 2014, Bermejo PMC1, (LPB, Z!); población de Copacabana , 19 October 2014, Bermejo SAM7 (LPB, Z!); Chapampa, 1 km S Copacabana, 16°11'S, 069°06'W, 3900 m, 31 July 1991, Kessler 2782; 2783; 2784; 3438; 3439; 3440; 3441; 3442; 3443; 3444; 3445; 3446; 3448; 3449; 3450; 3451; 3452; 3453; 3454; 3455; 3456; 3457; 3458; 3459; 3460; 3461; 3462; 3463; 3464; 3465; 3466; 3467; 3468; 3469; 3471; 3472; 3473; 3474; 3475; 3476; 3477; 3645 (GOET!); Hac. Challa, Isla del Sol , 3850 m, 01 August 1991, Kessler 3636; 3637; 3638; 3639; 3640 (GOET!); Cerro Kheñwani ( Orientación Sur-W) ladera rocosa, 3900 m, 22 January 1986, Liberman 1164 (GOET!). Murillo, ciudad de La Paz, Sector Kamirpata (Parche3) Dist. once, MacroDist. Periférica, area Forestal municipal, 16 September 2014, Bermejo 4 (LPB); PP-K 1 (LPB, Z!); PP-K3 (LPB, Z!); PP-K4 (LPB, Z!). Omasuyos, por la carretera entre Huarina y Kalaque, 16°09'04"S, 068°51'21"W, 3860 m, 22 February 2018, Fuentes 20182 (LPB). Insel Coaty, Lake Titicaca , 3840 m, 01 March 1910, Buchtien 4243 (GH!, GOET!); ciudad de La Paz, Av. Ballivian, 09 August 2010, Steudel 447 (Z!); 449 (Z!); Steudel 449b (Z!) .

Peru. Cusco: Quispicanchis, Dist. Huaro, Urpay , 13°41'01"S, 071°38'22"W, 3200 m, 01 November 2002, Galiano 4475 (CUZ!, F!, MO!) . Puno: Atuncolla, Lago Umayo, slope below Sillustani ruins, 4100 m, 04 September 2006, Kessler 13534; 13535; 13536 (GOET!). Lake Titicaca , Lake Titikaka , on Taquile Island , 3800 m, 23 July 1995, Lægaard 17730 (AAU!) .

Figures

Figure 79. Polylepis incarum (Bitter) M. Kessler & Schmidt-Leb A flowering branches B leaves C flowers D flowers E habit. Scale bars: 3 cm (A); 2 cm (B); 5 mm (C, D). Photographs A M. Kessler B-E A. Domic.

Figure 80. Polylepis incarum (Bitter) M. Kessler & Schmidt-Leb A flowering branch B lower leaf surface C upper leaf surface D fruit E stipular sheaths (A Laegaard 17730 B Beck 7689 C Kessler 3443 D, E Kessler 3640). Scale bars: 6 cm (A); 2 cm (B, C); 8 mm (D, E). Photographs by T. E. Boza E.

Figure 92. Geographical distribution of the species of subsection Polylepis Racemosae Racemosae.