Polylepis flavipila (Bitter) M.Kessler & Schmidt-Leb., Organisms 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

25. Polylepis flavipila (Bitter) M.Kessler & Schmidt-Leb., Organisms Diversity Evol. 6(1): 69. 2006.

Figs 67 , 68

Basionym.

Polylepis incana var. flavipila Bitter., Bot. Jahrb. Syst. 45: 640. 1911.

Type.

Peru. Huancavelica: Castro-Virreyna, western slopes of the Andes between Pisco and Ayacucho, 3900-4000 m, May 1910, Weberbauer 5433 (holotype: B destroyed; isotypes: F!, GH!, GOET!, US!).

Description.

Trees 3-8 m tall. Leaves slightly congested at the branch tips, imparipinnate with one pair of leaflets, obtrullate in outline, (1.9-)2.3-2.8 × 1.9-2.2 cm; rachises slightly villous, points of leaflet attachment with a tuft of long hairs; stipular sheaths not spurred, densely villous on the outer surfaces; leaflets obovate in outline, second pair from the terminal leaflet the largest, one of this pair (1.2-)1.6-2.0 × 0.6-0.8 cm; margin crenate with 4-6 teeth, apically acute or emarginate, basally cuneate; upper leaflet surfaces sparsely pilose; lower leaflet surfaces densely pilose with yellowish hairs 0.5-0.6 mm long. Inflorescences pendant, (2.7-)3.2-4.4 cm long, bearing 3-5 flowers; floral bracts 3.4-3.9 mm long, narrowly triangular, densely pilose on the outer surface; rachises pilose. Flowers 4.8-8.4 mm diam.; sepals 3-4, ovate, green to reddish, densely pilose outside; stamens 11-13, anthers orbicular, with a dense tuft of straight white hairs on the upper half; styles fimbriate, 2.4-3.2 mm long. Fruits turbinate, with 3-4 irregular flattened ridges with a series of spines, densely pilose; 4.1-5.2 × 2.4-4.2 mm including spines. Tetraploid.

Distribution, habitat and ecology.

Polylepis flavipila is distributed on the western Andean slope of central Peru in the Departments of Lima, Huancavelica and Ayacucho (Fig. 73 ). It grows in relatively dry and cold areas at 3300-4660 m elevation. In Nor-Yauyos Cochas (Lima), forests of P. flavipila have high floristic diversity, with 282 vascular plant species recorded, including 41 species endemics to Peru and 13 species categorized as threatened in Peru ( Trinidad and Cano 2016). The structure of P. flavipila forests is variable and depends on soil fertility and water availability ( Camel et al. 2019b). The water potential of the trees is influenced by elevation and soil factors ( Yaranga et al. 2021). An important factor that affects P. flavipila is the presence of the hemiparasite Tristerix chodatianus , which increases the mortality of the trees. The parasite damages the branches of the trees by causing water stress, forcing the host tree to increase its hydraulic conductivity which increases its vulnerability to drought and, about 15 years after colonization, leading to the death of the host branch ( Camel et al. 2019a). If many branches are affected, ultimately the whole tree may die.

Conservation status.

The EOO for Polylepis flavipila is estimated as 21,371 km2, the AOO is assessed at 132 km2, and it is known from 22 locations. It was categorized as VU (A1acd, B1+2c) in the World List of Threatened Trees ( Oldfield et al. 1998, as P. subsericans ) and as VU B1ab(iii) in the Red List of Threatened Flora of Peru ( Mendoza and León 2006). It is protected within the Nor Yauyos-Cocha Landscape Reserve. However, its populations are fragmented and severely threatened by overgrazing and logging and forest cover has been reduced by 53% between 1975 and 2020, based on satellite images ( Ames-Martínez et al. 2021). We assess P. flavipila as Endangered (B1a+B2a, C2a).

Notes.

This species was described by Bitter (1911) as a variety of P. incana and was placed in synonymy with P. subsericans by Simpson (1979), but elevated to species rank by Kessler and Schmidt-Lebuhn (2006) due to its morphological distinctness. Polylepis flavipila differs from P. subsericans by leaflet shape and margin (obovate with crenate margin versus narrowly elliptic with entire to slightly serrate margin) and different types of hairs (pilose versus strigose).

Specimens examined.

Peru. Ayacucho: Huamanga, Vinchos , 13°20'55"S, 074°27'28"W, 3100-3600 m, 29 September 2003, Mendoza & Roque 991 (MO!) . Huancavelica: Castrovirreyna, Chaupipata, 11°29'34"S, 074°56'37"W, 4200 m, 02 June 2016, Boza 3157; 3158; 3159; 3160; 3161; 3162; 3163; 3164; 3165; 3166; 3167; 3168 (USM!, Z!); cordillera between Pisco and Ayacucho, 3900-4000 m, 01 May 1910, Weberbauer 5433 (F!, GH!). Huancavelica, alrededores del Puente Licapa San Antonio, 13°22'39"S, 074°52'18"W, 4456 m, 19 June 2007, Beltrán 6391 (USM!); Dist. de Manta , localidad San Luis, cerca de la carretera que va hacia San Luis, 12°37'08"S, 075°09'43"W, 4350 m, 15 September 2017, Quispe 79 (CUZ!, USM!, Z!); Huaytamayoc-Tansiri, 4500 m, 01 May 1956, Tovar 2552 (USM!) . Lima: Canete, Cañete Valley, above Hortigal near madean, 12°57'S, 075°46'W, 3600 m, 07 March 1987, Brandbyge 237 (AAU!). Yauyos, Laraos, 12°23'S, 075°49'W, 04 February 2000, Beltrán 3394 (GOET!) .

Figures

Figure 67. Polylepis flavipila (Bitter) M. Kessler & Schmidt-Leb A flowering branch B upper leaf surface C lower leaf surface D leaves E habit F flowers G fruit (A, D Boza et al. 3157 B, C, G Quispe 79). Scale bars: 1 cm (A, D); 5 mm (B, C, F); 1 mm (G). Photographs A, D G. Vargas B, C, G T. E. Boza E. E, F H. R. Quispe.

Figure 68. Polylepis flavipila (Bitter) M. Kessler A flowering branch B fruit C stipular sheaths D lower leaf surface E upper leaf surface (A Beltran 6391 B-E Boza 3160). Scale bars: 2 cm (A, D, E); 3 mm (B). Photographs by T. E. Boza E.

Figure 73. Geographical distribution of the species of the sections Australes and Subsericantes.