Peru. Junin: Satipo, Pampa Hermosa, rural community of Santa Rosa de Toldopampa, buffer area of the Bosque de Proteccion Pui-Pui, 4221 m, 11°29'33.5"S, 74°56'37.8"W, 21 Apr 2015, Valenzuela & Rojas 28873 (holotype: HOXA!; isotypes: MO!, USM!).

Shrubs or trees 1–8 m tall. Leaves strongly congested at the branch tips, imparipinnate with 1 pair of lateral leaflets, obtrullate in outline, 1.4–1.6 × 1.5–2.0 cm; rachises glabrous, points of leaflet attachment with a tuft of long hairs; stipular sheaths apically with spurs, sparsely sericeous on the outer surfaces; leaflets elliptic in outline, second pair from the terminal leaflet the largest, one of this pair 0.9–1.1 × 0.4–0.6 cm; margin entire, apically emarginate with a projection of the mid-vein, basally unequally cordate; upper leaflet surfaces glabrous to sparsely sericeous; lower leaflet surfaces sparsely to densely sericeous with whitish hairs 0.8–1.0 mm long. Inflorescences upright, 0.9–1.1 cm long, bearing 1 flower; floral bracts 4.0–4.8 mm long, narrowly triangular, densely sericeous on the outer surface; rachises glabrous. Flowers 5.7–6.6 mm diam.; sepals 3, ovate, green, densely sericeous outside; stamens 9–10, anthers orbicular, with a dense tuft of straight white hairs on the upper half; styles fimbriate, 3.6–4.1 mm long. Fruits turbinate often slightly twisted, with variable numbers and placement of short spines, densely sericeous; 4.8–6.0 × 2.6–2.9 mm including spines. Diploid.

Polylepisrodolfovasquezii is distributed along the Eastern Cordillera of central Peru from San Martin to Cusco and Puno (Fig. 24). It occurs on wet rocky slopes at 3700–4750 m elevation. It commonly grows with trees of the genera Escallonia, Gynoxys, Hesperomeles and Clethra (Valenzuela and Villalba 2015). Growth of this species is most strongly correlated to growth season temperature (Requena-Rojas et al. 2020a, 2020b). Polylepisrodolfovasquezii remnants harbor several threatened bird species, including Anairetesalpinus (Quispe-Melgar et al. 2018, 2020).

The estimated EOO is 164,207 km² and AOO is 116 km². The species is known from 19 locations. Although it is protected within the Pui-Pui Protection Forest in Junin, the species was categorized as VU for Peru (SERFOR 2006, as P.pepei). Burning activities for the expansion of pastures for livestock grazing are causing a reduction of the small remnants, even within the protected area. We assess P.rodolfovasquezii as Vulnerable (A1, B1a+B2a, C1).

Specimens of this recently described species were long identified as Polylepispepei, based on their very similar morphology. However, P.rodolfovasquezii differs from P.pepei by having only one pair of lateral leaflets (versus two pairs) and shorter inflorescences (0.9–1.1 cm long) bearing just one flower (versus 1.2–1.6(–3.5) cm long bearing three flowers). When Polylepisrodolfovasquezii was described by Valenzuela and Villalba (2015), they did not realize that their newly described species had been treated as P.pepei since Simpson (1979). Nevertheless, Simpson (1979) already mentioned that “the collection from Peru has only one pair of leaflets, reduced inflorescences and denser covering of trichomes on the under-leaflet surfaces”. Despite these differences from the Bolivian specimens, she recognized just the single taxon P.pepei. This was presumably the result of the low number of specimens known for the two species at that time and the broad species concept adopted by Simpson. Clearly, the two species are closely related allopatric taxa that could conceivably also be treated as subspecies.

Polylepisrodolfovasquezii also resembles P.subsericans and P.flavipila. It differs from these in its shorter inflorescence (0.9–1.1 cm) bearing just one flower, whereas in P.subsericans, the inflorescences are 1.9–5.6 cm long with 3–6 flowers and in P.flaviplia 2.7–4.4 cm long with 3–5 flowers.

Peru. Cusco: La Convención, bosque de Mandor, 4200 m, 01 October 2004, Palomino 2043 (QCA!); Dist. Santa Teresa, Mountain edges on the lower Eastern portion of the Phachaq valley, Yanama, 13°17'11"S, 072°50'13"W, 4232 m, 28 April 2012, Sylvester 1451 (Z!); Dist. de Ollantaytambo, Mountain edges on the lower Eastern portion of the Phachaq valley, Yanama, 13°17'12”S, 072°50'13"W, 4211 m, 01 May 2012, Sylvester 1501 (Z!); Dist. de Santa Teresa, grazed slopes in the central Pacchaq valley on the East side of the river Yanama, 13°15'40"S, 072°50'17"W, 4268 m, 04 May 2012, Sylvester 1558 (Z!); Dist. Santa Teresa, Mountain edges on the lower Eastern portion of the Phachaq valley, Yanama, 13°17'12"S, 072°50'13"W, 4174 m, 05 May 2012, Sylvester 1564 (Z!); Dist. de Ollantaytambo, topmost forest found on the lower North side of the lower Phachaq valley, Yanama, 13°17'01"S, 072°50'01"W, 4566 m, 15 May 2012, Sylvester 1597 (Z!); 1598 (Z!). Urubamba, Q’esqa, 3960 m, 01 September 2002, Arce s. n. (USM!); Abra Malaga, 13°08'46"S, 072°18'14"W, 4284 m, 01 October 2002, Arce s.n (USM!); Paljay, 13°08'46"S, 072°18'14"W, 4177 m, 01 September 2002, Arce s.n (CUZ!); Chaupiwayco, 13°14'59"S, 072°29'10"W, 4290 m, 01 May 2002, Arce s.n (CUZ!); Piñasniocj, Panticalla pass, 3600 m, 15 July 1915, Cook 1241 (US!); 1837 (US!); Cañon above Peñas ruins towards Nevado Veronica, Peñas Cañon beyond Ollantaytambo on road to Abra Malaga, 4100 m, 26 August 1989, Driesch s.n (GOET!); Cumbre Malaga, 01 October 1984, Rivas s.n (USM!); Dist. de Ollantaytambo, Congunayoc; 3.5 km 175 South of the village Thastayoc, on SE facing slope facing towards Ollantaytambo, 13°10'26"S, 072°16'06"W, 4438 m, 09 March 2012, Sylvester 1392 (Z!); 13°10'24"S, 072°16'14"W, 4415 m, 09 March 2012, Sylvester 1393 (Z!); 13°10'26"S, 072°16'06"W, 4427 m, 10 March 2012, Sylvester 1396 (Z!); 13°10'22"S, 072°16'11"W, 4417 m, 10 March 2012, Sylvester 1397 (Z!); 13°10'25"S, 072°16'14"W, 4414 m, 10 March 2012, Sylvester 1398 (Z!); Machupicchu, Warmiwañuska, 13°14'21"S, 072°29'06"W, 4235 m, 13 September 2006, Toivonen 67; 68; 69; 70; 71; 72; 73; 74; 75; 80 (CUZ!); Ollantaytambo, Abra Malaga, 13°08'40"S, 072°17'51"W, 4340 m, 10 May 2006, Toivonen 82 (CUZ!); Dist. Machupicchu, Microcuenca Pacaymayo; laguna Pacaymayo, 13°13'48"S, 072°29'48"W, 3900 m, 26 June 2001, Tupayachi 5049 (CUZ!); Machupicchu Microcuenca Cusichaca, Sisaypampa Abra Palkay, 13°20'00"S, 072°30'44"W, 4100 m, 28 June 2001, Tupayachi 5155 (CUZ!); 4350 m, 01 July 1915, Bingham 2068 (US!). Junín: Concepcion, Dist. de Comas, localidad de Pomamanta, 11°44'24"S, 075°09'39"W, 4400 m, 23 August 2017, Quispe 76 (CUZ!, USM!, Z!). Satipo, Pampa Hermosa, Toldopampa, 11°29'34"S, 074°56'37"W, 4160 m, 02 August 2016, Boza 3169; 3170; 3171; 3172; 3173; 3174; 3175; 3176; 3177; 3178 (USM!, Z!); Pampa Hermosa. Toldopampa, 13°12'15"S, 075°20'22"W, 4131 m, 02 August 2016, Boza 3179 (USM!, Z!); 3180 (USM!, Z!); Dist. Pampa Hermosa, Comunidad Campesina Santa Rosa de Toldopampa, 11°29'34"S, 074°56'38"W, 4221 m, 21 April 2015, Valenzuela 28873 (HOXA, MO!, USM!). Puno: Limbani, Huancasayani on road to Limbani just east of Abra Aricoma, 14°13'S, 069°42'W, 3750 m, 28 March 1987, Boertmann 130 (AAU!); 512 (AAU!). San Martín: Mariscal Caceres, Dist. de Huicungo, Callejón de Corneadas, 07°57'46"S, 077°23'23"W, 3925 m, 11 June 2001, León 5153 (USM!); Dist. Huicungo, en pirca, debajo del camino de abra Ventanas y Laguna Colorada, 08°00'53"S, 077°23'30"W, 3924 m, 20 June 2010, León 5539 (USM!). San Martín, Dist. de Huicungo, cerca a Laguna Colorada, camino al abra Ventanas, 3900 m, 18 June 2001, León 5260 (USM!).