Polylepis incanoides (M.Kessler) T.Boza & M.Kessler,, 2022

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

42. Polylepis incanoides (M.Kessler) T.Boza & M.Kessler, comb. et stat. nov.

Figs 108 , 109

Polylepis tomentella subsp. incanoides M.Kessler, Candollea 50(1): 164. 1995. Type. based on Polylepis incanoides (M.Kessler) T.Boza & M.Kessler.

Type.

Bolivia. Dept. Cochabamba, Prov. Carrasco, surroundings of Monte Punco , l 7°36'S, 65°17'W, 2800 m, 14 Aug1991, Kessler 2954 (holotype: LPB!; isotypes: AUU!, GOET!) .

Description.

Trees to 2-5 m tall. Leaves slightly congested at the branch tips, imparipinnate with one pair of leaflets, trullate in outline, 2.3-4.1 × 2.0-3.7 cm; rachises sparsely villous, points of leaflet attachment with a tuft of long hairs; stipular sheaths apically truncate, glabrescent to sparsely villous on the outer surfaces; leaflets obovate in outline, second pair from the terminal leaflet the largest, one of this pair 1.3-2.0 × 0.5-0.7 cm; margin serrate with 7-15 teeth, apically obtuse to slightly acute, basally unequally attenuate; upper leaflet surfaces glabrous to sparsely villous on mid-vein depression; lower leaflet surfaces with a dense layer of very short, white or yellowish pannose hairs. Inflorescences pendant, 3.2-3.7 cm long, bearing 5-7 flowers; floral bracts 2.6-4.6 mm long, narrowly triangular, densely villous on the outer surface; rachises villous. Flowers 5.5-7.1 mm diam.; sepals 3, ovate, green, glabrous or sparsely villous outside; stamens 15-19, anthers orbicular, with a dense tuft of straight white hairs on the upper half; styles fimbriate, 1.8-2.1(-2.7) mm long. Fruits turbinate, with 3-4 irregular flattened ridges with a series of spines, densely villous; 3.9-4.8 × 3.1-4.5 mm including spines. Tetraploid.

Distribution, habitat and ecology.

Polylepis incanoides occurs in small populations in Cochabamba (Bolivia). It grows mainly in relatively dry areas at 2650-3750 m elevation (Fig. 116 ). It occurs as homogeneous stands or in mixed stands with Podocarpus parlatorei , Alnus acuminata , Clethra sp., Weinmannia sp., Schinopsis haenkeana and Aspidosperma quebracho-blanco at its distributional limits ( Kessler 1995b). Kessler (1995b) reported hybrids between P. incanoides and both P. besseri and P. subtusalbida at their narrow sympatry zones.

Conservation status.

The EOO for Polylepis incanoides is estimated as 5,649 km2, the AOO is assessed at 64 km2, and it is known from 11 locations. No conservation action has been taken to date. The species was categorized as VU (B1+2c, D2) in the World List of Threatened Trees ( Oldfield et al. 1998). However, based on its restricted distribution in Cochabamba, P. incanoides was categoriszed as EN (B2ab(i,ii,iii)) in Bolivia ( Arrázola and Coronado 2012). The best-preserved remnant forests are found in the north-western mountains of Epizana ( Navarro et al. 2010). Based on its fragmented distribution and degraded habitat, we assess P. incanoides as Endangered (A1+A2a, B1a+B2a, D1).

Notes.

Polylepis incanoides is very similar to P. tomentella and, in fact, it was treated as a subspecies of P. tomentella by Kessler (1995b). We here elevate P. incanoides to species rank based on morphological, ecological and biogeographical grounds. Polylepis incanoides differs from P. tomentella by leaflet apex (obtuse to slightly acute versus round to emarginate), inflorescence length (3.2-3.7 cm versus 2.8-5.3 cm), number of flowers (5-7 versus 4-5) and stamen number (15-19 versus 19-23). In addition, within its geographically restricted and isolated range, P. incanoides grows under significantly higher temperatures and levels of precipitation than P. tomentella .

Specimens examined.

Bolivia. Cochabamba: Arani, al borde de la carretera Cochabamba-Santa Cruz, 3400 m, 04 November 1988, Hensen 222 (GOET!, LPB); Mojon, 1 km N Cochabamba-Sta Cruz road, 17°29'S, 065°25'W, 3000 m, 14 August 1991, Kessler 2943 (GOET!, LPB); 6 km E Mojon on Cochabamba-Comarapa road, 17°30'S, 065°23'W, 2850 m, 05 October 1991, Kessler 3287, 3288 (GOET!, LPB); 3289 (GOET!, MO!). Arque, proximidades a la comunidad de Kutimarca y Sumuruni, camino hacia Arque, 3850 m, 11 April 1999, Mercado 2169 (MO!). Carrasco, Cochabamba 142 km hacia Santa Cruz, 16°58'25"S, 065°20'49"W, 3050 m, 24 March 1981, Beck 6827 (GOET!, LPB, MO!); Cochabamba 161 km hacia Santa Cruz, 3100 m, 27 September 1981, Beck 7047 (GOET!, LPB, MO!); Epizana, 3000 m, 01 November 1954, Cardenas 5221 (US!); 2 km despues de Totora , 2900 m, 20 February 1979, Ceballos 407 (G); Carretera Fundamental 4.7 km E Epizana, 2956 m, 05 December 1975, Davidson 3760 (F!, NY); Montepunco, Canyon of Rio Huairamayu (R. Montepunco) 40 km N of Totora, 2800 m, 22 August 1947, Fosberg 28456 (NY); Llutupampa, 3300 m, 14 April 1991, Hensen 2416 (LPB); 2420 (GOET!); Llutupampa, 3100 m, 14 April 1991, Hensen 2450; 2463; 2473 (LPB); Surroundings of Monte Punco , 17°36'S, 065°17'W, 2800 m, 14 August 1991, Kessler 2953 (GOET!); 2954; 2955 (AAU!, GOET!); 3 km E Epizana on Cochabamba-Comarapa road, 17°40'S, 065°05'W, 3000 m, 05 October 1991, Kessler 3290 (GOET!); 8 km E Epizana on Cochabamba-Comarapa road, 17°41'S, 065°04'W, 3000 m, 05 October 1991, Kessler 3292 (GOET!); 3293 (AAU!, GOET!); 81 miles our of Cochabamba on road to Santa Cruz, 9400 ft, 13 November 1959, Maguire 44482 (GH!, NY, US!); Km. 135 hacia Totora , proximidades del lugar llamado Cañada hornillas, 17°44'07"S, 065°11'28"W, 3000 m, 21 March 1999, Mercado 1970 (MO!); 8.7 km al este de Epizana por el camino entre Cochabamba y Santa Cruz, 17°40'S, 065°09'W, 3200 m, 04 February 1987, Solomon 15922 (MO!, NY); Subiendo el Rio Mizque hacia Totora pasando Totora , 17°45'S, 065°12'W, 20 October 1995, Torrico 713 (LPB). Mizque, Khuchu 23 km E Vacas, 3500 m, 03 March 1991, Hensen 1924 (LPB). Totora , Totora and Duraznillo, 17°44'00"S, 065°11'00"W, 2500 m, 20 December 1921, Steinbach 6031 (A!, G). a unos 97 km de la capital en dirección a Santa Cruz, matorral alto, 3565 m, 25 December 1982, Fernández 3565 (MO!) . Potosí: Charcas, de Acasio 23 km hacia Uncia, 1 km antes del desvío a San Pedro, 18°06'36"S, 066°06'26"W, 3450 m, 02 February 2015, Beck 34512 (LPB); entre Caracollo y Cochabamba, Pongo, Kulku Mayu, 3800 m, 24 December 1982, Fernández 7699 (MO!) .

Figures

Figure 108. Polylepis incanoides (M. Kessler) T. Boza & M. Kessler. Habit. Photograph M. Kessler.

Figure 109. Polylepis incanoides (M. Kessler) T. Boza & M. Kessler A flowering branch B stipular sheaths C upper leaf surface D lower leaf surface E fruits (A, C-E Peterson 12723 B Kessler 2953). Scale bars: 8 cm (A); 2 cm (C, D); 4 mm (D, E). Photographs by T. E. Boza E.

Figure 116. Geographical distribution of the species of subsection Polylepis Incanaee Incanaee.