Peru. Puno: Prov. Azangaro, Muñani, ca. 3650 m, Weberbauer 1369 (holotype: B destroyed; isotypes: F!, GOET!).

Trees 2–13 m tall. Leaves slightly congested at the branch tips, imparipinnate with 1(–2) pairs of leaflets, obtrullate in outline, 2.6–4.0 × 2.8–4.0 cm; rachises densely villous, points of leaflet attachment with a tuft of long hairs; stipular sheaths apically truncate, densely villous on the outer surfaces; leaflets elliptic in outline, second pair from the terminal leaflet the largest, one of this pair 1.2–2.0 × 0.5–0.8 cm; margin crenate with 5–8 teeth, apically round or emarginate, basally unequally cordate; upper leaflet surfaces slightly rugose, glabrous to sparsely villous; lower leaflet surfaces with a dense layer of very short, white pannose hairs. Inflorescences pendant, 2.7–6.0 cm long, bearing 5–6 flowers; floral bracts 4.2–4.9 mm long, narrowly triangular, densely villous on the outer surface; rachises villous. Flowers 6.8–9.2 mm diam.; sepals 4, ovate, green, densely villous outside; stamens 17–21, anthers orbicular, with a dense tuft of straight white hairs on the upper half; styles fimbriate, 3.3–3.6 mm long. Fruits turbinate, with 2–3 irregular flattened ridges with a series of spines, densely villous; 4.4–5.9 × 3.8–5.9 mm including spines. Tetraploid.

Polylepispallidistigma is distributed in southern Peru from southern Cusco to Puno (Fig. 103). It grows on relatively dry slopes at 3700–4580 m elevation in a region with calcareous rocks. It typically grows on rocky outcrops (Yallico 1992, as P.incana). Average tree height of P.pallidistigma is 2.5–5.0 m with diameters of 5–15 cm (ECOAN 2006). Polylepispallidistigma patches harbour some of the most specialized and endangered of bird species, such as Anairetesalpinus (Endangered) and Leptasthenurayanacensis (Near Threatened) in the forests of Lawa Lawani and Chingo (Carabaya Province), Asthenesarequipae and Leptasthenuraandicola in the Torno (Huancane Province), Bellavista and Quilcapuncu forests (San Antonio de Putina Province) and Conirostrumbinghami (= Oreomanesfraseri) (Near Threatened) present in all evaluated forests (ECOAN 2006).

The EOO for Polylepispallidistigma is estimated as 17,670 km², the AOO is assessed at 112 km² and it is known from 17 locations. No protection action has been taken to date. We assess P.pallidistigma as Vulnerable (B1a+B2a).

Polylepispallidistigma was treated as a synonym of P.besseri by previous authors (e.g., Simpson 1979; Kessler 1995b) and a synonym of P.subtusalbida by Mendoza and Cano (2012). However, based on its distinct morphology, ecology and distribution, we consider that this taxon should be recognized as different from P.besseri and P.subtusalbida. Polylepispallidistigma differs from P.besseri by having longer and narrower elliptic leaflets 1.2–2.0 × 0.5–0.8 cm with the lower leaflet surfaces with a dense layer of very short of pannose hairs, whereas P.besseri has shorter and broader obovate leaflets 1.4–1.6 × 0.6–1.1 cm with the layer of pannose hairs and mixed with densely tomentose hairs. Further, P.pallidistigma has a lower number of flowers per inflorescence (5–6) and longer styles (3.3–3.6 mm), whereas P.besseri has 7–9 flowers and styles 2.5–3.1 cm long. Polylepispallidistigma differs from P.subtusalbida by larger elliptic leaflets (1.2–2.0 × 0.5–0.8 cm versus 0.9–1.6 × 0.4–0.6 cm) with different margins (crenate versus serrate), different hair type of the lower leaflet surfaces (pannose versus tomentose), relatively longer inflorescences (2.7–6.0 cm versus 1.8–3.7 cm) with more flowers per inflorescence (5–6 versus 3–4) and longer styles (3.3–3.6 mm versus 2.8–3.4 mm).

Peru. Cusco: Espinar, Zona del Mamaniwaita, 3900–4100 m, 13 July 1967, Vargas 19893 (CUZ!). Puno: Azangaro, Putina, 4200 m, 04 April 1959, Vargas 12528 (CUZ!); Carabaya, Coasa, Chingo, 14°02'25"S, 70°08'07"W, 4299 m, 07 October 2014, Boza 3005 (USM!, Z!); Coasa. Chingo, 14°02'49"S, 070°09'19"W, 4511 m, 07 October 2015, Boza 3006 (USM!, Z!); Entre Macusanin Nuñoa, 4000 m, 29 February 1948, Vargas 7139 (CUZ!, MO!). Huancane, rock outcrop 450 m East of the Huancane coliseo, 15°11'40"S, 069°45'26"W, 3910 m, 06 November 2012, Sylvester 1822 (CUZ!, Z!); 900 m East up the slope from the Huancane coliseo in the centre of the main Polylepis forest, 15°11'32"S, 069°45'21"W, 3999 m, 06 November 2012, Sylvester 1825; 1827 (CUZ!, Z!); 700 m East up the slope from the Huancane coliseo in the centre of the main Polylepis forest, 15°11'35"S, 069°45'26"W, 3927 m, 06 November 2012, Sylvester 1829 (CUZ!, Z!); 500 m East up the slope from the Huancane coliseo in the centre of the main Polylepis forest, 15°11'38"S, 069°45'28"W, 3892 m, 06 November 2012, Sylvester 1830; 1831 (CUZ!, Z!). Lampa, Quebrada Metara, 15°10'S, 070°22'W, 3880 m, 01 April 1987, Boertmann 136; 137; 138; 139 (AAU!); Pampa Changanchaca between Lampa and Pucara, 15°10'S, 070°22'W, 3800 m, 02 April 1987, Boertmann 141 (AAU!); Inticancha in lower Quebrada Metara N of Centro Yaurinco, 15°10'S, 070°22'W, 3850–4000 m, 01 April 1987, Brandbyge 569; 573 (AAU!); Cerro Chacapacha, 3900–4000 m, 21 May 1988, Del Carpio 728; 729 (USM!); Cara-cara, cerca a Pucará, 3900 m, 27 September 1984, Fernández 544 (USM!); Inticancha in lower Quebrada Metara N of Cerro Yaurinco, 15°10'S, 070°22'W, 3850–4000 m, 01 April 1987, Kessler 573 (AAU!); Areas rocosas, Lamparaquen, 15°19'00"S, 070°27'00"W, 4130 m, 06 June 2009, Montesinos 2675 (USM!); SW facing slope 900 m NE of a large lake 8.5 km East of Lampa, close to the hamlet Chañacahua, 15°23'11"S, 070°17'22"W, 3986 m, 06 November 2012, Sylvester 1802 (CUZ!, Z!); Base of south facing cliff on the south facing slope overlooking the hamlet of Chañacahua, 15°22'54"S, 070°17'04"W, 4075 m, 06 November 2012, Sylvester 1816 (CUZ!, Z!); Alrededores de Pucará, 3850–3900 m, 12 March 1966, Tovar 5342 (USM!); Laderas de Pucará, 3850 m, 03 November 1966, Vargas 18293 (CUZ!); Lampa, 3900–4400 m, 25 March 1988, Velásquez 1; 2; 3; 4; 8; 9; 11 (MO!); Melgar, Ñuñoa, 14°28'24"S, 070°35'43"W, 4038 m, 06 October 2014, Boza 3003 (USM!, Z!); Ñuñoa, 14°25'38"S, 070°34'01"W, 4094 m, 06 October 2014, Boza 3004 (USM!, Z!). Palca, Palca, 15°15'08"S, 070°32'05"W, 3960 m, 04 April 2005, Aedo 11124 (USM!). Puno, Slopes east of Puno, 3800 m, 29 January 1975, Antunez de Mayolo 87 (USM!); On dry places, 3125 m, 02 January 1920, Shepard 150 (A!). San Antonio de Putina, Quilcapuncu, 14°54'20"S, 069°45'18"W, 3952 m, 08 October 2014, Boza 3007 (CUZ!, USM!); Near Puno, 4000 m, 01 July 1936, Soukup 365 (F!).