Polylepis argentea T.Boza & H.R.Quispe, 2019

2. Polylepis argentea T.Boza & H.R.Quispe View in CoL sp. nov.

TYPE: PERU. Dpto. Jun´ın: Prov. Concepción, Distrito de Andamarca , a 2.5 km de la localidad de Alhuay , [11°41 ' 30" S 74°54 ' 01" W], 4150 m, 10 Oct 2017, H.R. Quispe M. 85 (holotype: CUZ!; GoogleMaps isotype: USM!, Z!) .

This species differs from the morphologically closest species Polylepis sericea Wedd. in having longer and narrower leaflets, upper leaflet surfaces almost glabrous with some hairs on the midveins, and longer inflorescences.

Trees 4–7 m tall. Leaves strongly congested at the branch tips, imparipinnate with 3 pairs of leaflets, obtrullate in outline, (2.9)3.3–4.3 X (2.6–) 3.3–4.3 cm; rachises densely sericeous, points of leaflet attachment with a tuft of long, straight hairs, sometimes with resin at leaflet insertion; stipular sheaths apically acute with spurs, densely sericeous on the outer surfaces; leaflets narrowly elliptic in outline, second pair from the terminal leaflet the largest, one of this pair (1.9)2.4–2.6 X 0.5–0.7 cm; margin entire, coriaceous, apically acute to slightly retuse, basally unequally cordate; upper leaflet surfaces almost glabrous with some hairs on the midveins to densely sericeous with silky hairs throughout; lower leaflet surfaces densely sericeous with silky hairs 0.6–0.9 mm long. Inflorescences pendent, 7.2–8.1 cm long, bearing 5–6(–9) flowers; floral bracts 4.5–5.6 mm long, narrowly triangular, densely sericeous on the outer surface; rachises sericeous. Flowers 7–9 mm diam; sepals 3–4, ovate, green, densely sericeous outside; stamens 7–10, anthers orbicular, with a dense tuft of straight white hairs on the upper half; styles fimbriate, 2.7–4 4 mm long. Fruits turbinate, with variable numbers and placement of flattened spines, densely sericeous; 2.3–2.5 X 3.5–5.3 mm including spines. Figure 3 View FIG .

Distribution and Habitat — Polylepis argentea has been found in central Peru at La Mar (Ayacucho), Concepcion, Huancayo, and Satipo (Junin), and La Convencion and Urubamba (Cusco). It grows mainly in humid Andean forest at 2000–4340 m elevation. It often co-occurs with P. pauta , P. rodolfo-vasquezii , and P. canoi , and although hybrids are not yet known, these might occur ( Fig. 2 View FIG ).

Etymology —The species epithet “ argentea ” (Latin: silvery) refers to the silvery white hairs that have a metallic lustre.

Conservation Status —The estimated extent of occurrence (EOO) for Polylepis argentea is 23,787 km 2. The mapped area of suitable habitat produces an estimate of the occupied habitat or Area of Occupancy (AOO) of 40 km 2. This would qualify the species as VU or Vulnerable, according to IUCN (2015) criteria and categories. Boyle (2001) described extensive forest of this species in the remote Cordillera Vilcabamba.

Notes — Polylepis argentea seems morphologically closest to P. sericea and P. canoi with which it shares similar lower leaflet surfaces hairs type and density. The most obvious differences between P. argentea and these species is leaflet size, with P. argentea having leaflets of 1.9–2.6 X 0.5–0.7 cm, whereas P. canoi has leaflets of 2.4–3.9 X 0.8–1.5 cm and P. sericea of 1.8–2.1 X 0.8–1.0 cm. Further, P. argentea has shorter hairs (0.6–0.9 mm vs. 1.3–1.7 mm) than P. canoi . In P. canoi , the hairs on the lower leaflet surfaces are yellowish and often most pronounced on the secondary veins, whereas in P. argentea they are silky and more evenly distributed. Polylepis argentea has the upper leaflet surfaces with a few hairs on midveins whereas P. sericea has totally glabrous upper leaflet surfaces. Additionally, the inflorescence length and number of flowers per inflorescence differ between the species, with P. argentea having inflorescences 7.2–8.1 cm long with 5–9 flowers, compared with values of 3.3–4.5 cm and 9–15 flowers in P. sericea , and 8.2–14.5 cm and 12–26 flowers in P. canoi . The three species can also be distinguished by the number of stamens and style length, with P. argentea having 7–10 stamens and styles 2.7–4.4 mm long, whereas the other two species have 13–15 stamens and styles 2.4–3.8 mm in P. canoi and 1.9–2.5 mm in P. sericea .

Polylepis argentea View in CoL was first collected by B. Boyle during scientific expeditions carried out in 1997 and 1998 to the isolated Cordillera Vilcabamba where he recorded three species of Polylepis ( Boyle 2001) View in CoL . The first one he called Polylepis sp1 and described as “a tree of 4–5 m with rather small silverytomentose leaflets” (specimen Boyle 4149) dominating the fractured forest. A second species of Polylepis View in CoL “with fewer, darker green and nearly glabrous leaflets” called Polylepis cf. sericea View in CoL (Boyle 4151), occurred patchily within stands of Polylepis sp1 as well as in monospecific stands. The third species mentioned was Polylepis cf. pauta View in CoL (Boyle 4398), described as “a common tall tree (to 25 m high) in the tall hilltop forest.” “The slightly different colours of the foliage of each species of Polylepis View in CoL made this gradation obvious even from a distance” ( Boyle 2001). Disentangling these three species based on Boyle’ s specimens we assign them as follows: Polylepis sp1 is P. argentea View in CoL , P. cf. sericea View in CoL is P. canoi View in CoL , and P. cf. pauta View in CoL is indeed P. pauta View in CoL .

Additional Specimens Examined — Peru. — JUNÍN: Concepcion. Andamarca , 14 Jun 2002, G. Martinez N. 18 ( USM) ; Satipo.Satipo/ La Convencion Cordillera Vilcabamba Rio Ene slope, near summit of divide, 11°39 ' 30"S 073°40 ' 02"W, 07 Jun 1997, B. Boyle et al. 4149 ( USM) GoogleMaps ; Huancayo. Distrito de Santo Domingo de Acobamba. A 5 km de la localidad de Callanca . 508608, 8699728, 11°45 ' 43"S 074°55 ' 15"W, 12 Oct 2017, H. R. Quispe M. 87 ( CUZ, USM, Z) GoogleMaps . — AYACUCHO: La Mar. Dist. Tambo. Estera Community , Sector Muyuorco , 12°54 ' 19"S 073°48 ' 17"W, 29 Jun 2015, T. E. Boza E. et al. 3036 ( USM, Z), 3096 ( USM, Z), 3097 ( USM, Z), 3098 ( USM, Z), 3099 ( USM, Z), 3100 ( USM, Z), 3101 ( USM, Z), 3102 ( USM, Z), 3103 ( USM, Z), 3104 ( USM, Z), 3105 ( USM, Z), 3106 ( USM, Z) GoogleMaps . — CUSCO: La Convención. Dist. Huayopata. Abra Málaga , 13°08 ' 05"S 072°19 ' 18"W, 13 Jun 2015, T. E. Boza E. & E. Urquiaga 3032 ( USM, Z), 3082 ( USM, Z), 3083 ( USM, Z), 3084 ( USM, Z) GoogleMaps ; Dist. Huayopata. Localidad Panticalle , Abra Málaga, [13°08 ' 02"S 072°19 ' 32"W], 30 May 2006, J. Toivonen M. & L. Puelles 84 ( CUZ), 85 ( CUZ), 86 ( CUZ), 87 ( CUZ) GoogleMaps ; Urubamba. Dist. Ollantaytambo, Huaytampo, Bosque primario, 13°10 ' 47"S 072°21 ' 10"W, 07 Nov 2002, G. Calatayud et al. 1035 ( CUZ, F, MO, USM) GoogleMaps ; Santuario Histórico Machu Pichu, camino Inca, Km 88–112, por puente Ruinas, 13°18’S 072°07’W, 20–21 Jun 1988, P. Nú~ nez V. & A. Pyrke 9204 ( MO) GoogleMaps ; Inkatambo , [13°18 ' 06"S 072°31 ' 44"W], Sep 2002, R. Arce & J. Toivonen M. s.n. ( CUZ) GoogleMaps ; Abra Málaga , [13°08 ' 43"S 072°18 ' 09"W], Oct 2002, R. Arce & J. Toivonen M. s.n. ( CUZ) GoogleMaps ; Qésqa , [13°17 ' 51"S 072°24 ' 57"W], Oct 2002, R. Arce & J. Toivonen M. s.n. ( USM) GoogleMaps ; Inkatambo , 13°18 ' 06"S 072°31 ' 44"W, Sep 2002, R. Arce & J. Toivonen M. s.n. ( USM) GoogleMaps ; Distrito Ollantaytambo. Localidad Abra Málaga, [13°09 ' 02"S 072°18 ' 09"W], 29 May 2006, J. Toivonen M. & L. Puelles 15 ( CUZ), 16 ( CUZ) GoogleMaps ; Dist. Ollantaytambo. Localidad Huaytampo , [13°10 ' 31"S 072°21 ' 03"W], 06 Jul 2006, J. Toivonen M. & L. Puelles 95 ( CUZ), 96 ( CUZ) GoogleMaps .