Polylepis racemosa Ruiz & Pav., Syst. Veg. Fl. Peruv. Chil. 139. 1798.

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

32. Polylepis racemosa Ruiz & Pav., Syst. Veg. Fl. Peruv. Chil. 139. 1798.

Figs 85 , 86

Polylepis villosa Humboldt, Bonpland and Kunth, Nov. Gen. Sp. (quarto ed.) 6: 228. 1824. Type. Peru. Caxamarca: 8784 ft. (2700 m), Aug 1802, Bonpland 3685 (holotype: P!; isotype: P!).

Polylepis incana subsp icosandra Bitter, Bot. Jahrb. Syst. 45: 641. 1911. Type. Peru. Ancash: Cajatambo, between Tallenga and Piscapaccha, Weberbaueri 2886 (holotype: B destroyed).

Polylepis incana subsp. micranthera Bitter, Bot. Jahrb. Syst. 45: 642. 1911. Type. Peru. Huanúco: Sierra, Caxamarquilla, without collector (holotype: W!).

Polylepis incana var. primovestita Bitter, Bot. Jahrb. Syst. 45: 645. 1911. Type. Peru. Caxamarquilla: Ruiz s.n An illegitimate name since it is based on the same collection as the type of P. racemosa .

Polylepis incana var. connectens Bitter (1911:645). Type. Peru, Huanúco: mountains of Huanúco, Haenke s.n (holotype: PR).

Type.

Peru. Caxamarquilla and Pillao Ruiz s.n (holotype: P!; isotype: G!).

Description.

Trees 2-15 m tall. Leaves slightly congested at the branch tips, imparipinnate with 1-2 pairs of leaflets, obtrullate in outline, (3.9-)4.5-5.8(-6.5) × (2.6-)3.1-4.6(-6.1) cm; rachises densely villous, points of leaflet attachment with a tuft of long hairs; stipular sheaths apically acute, glabrescent on the outer surfaces with long trichomes at the apex; leaflets obovate in outline, second pair from the terminal leaflet the largest, one of this pair (2.3-)3.1-3.9 × (0.7-)0.9-1.5 cm; margin serrate with 8-14 teeth, apically round, basally attenuate to unequally cordate; upper leaflet surfaces glabrous; lower leaflet surfaces sparsely to densely tomentose with yellowish hairs 0.4-1.5(-2.0) mm long. Inflorescences pendant, (4.2-)5.0-9.4(-11.7) cm long, bearing 7-21 flowers; floral bracts (3.8-)4.6-6.0 mm long, narrowly triangular, densely tomentose on the outer surface; rachises villous. Flowers (6.6-)7.8-8.1(-11.9) mm diam.; sepals 4, ovate, green, densely villous outside; stamens 9-19, anthers orbicular, with a dense tuft of straight white hairs on the upper half; styles fimbriate, 2.2-3.7 mm long. Fruits turbinate, with 2-5 irregular ridges with a series of spines, densely pilose; (4.2-)5.0-8.1(-10.3) × (3.3-)3.8-6.0 mm including spines. Tetraploid to octoploid with many intermediates.

Distribution, habitat and ecology.

Polylepis racemosa has been recorded from Cajamarca to Cusco in Peru and, in recent decades, has been introduced to Ecuador from Pichincha to Azuay (Fig. 92 ). It has been recorded at 2750-4660 m elevation. To our knowledge, all records of this species refer to planted individuals, mostly close to villages and houses. Polylepis racemosa is probably the fastest growing species of the genus ( Montalvo et al. 2018; Rosero et al. 2018), presumably as a result of hybridogenic polyploidy and associated hybrid vigor. This species is currently being widely used in reforestation programmes in the Andes of Ecuador and Peru.

Conservation status.

The EOO for Polylepis racemosa is estimated as 461,319 km2, the AOO is assessed at 128 km2 and it is known from 24 locations. The species was categorized as VU (A1c) in the World List of Threatened Trees ( Oldfield et al. 1998). In Peru, it has been categorized as CR ( SERFOR 2006). This species is fast-growing, more ecologically adaptable than others in the genus and extensively used for reforestation and agroforestry. We assess P. racemosa as Least Concern (B1a+B2a), unless a natural population is found, which would then be of high conservation concern.

Polylepis racemosa has been observed to hybridize with other species of Polylepis , potentially threatening the genetic integrity of natural Polylepis populations. This process is especially apparent in Ecuador, where the species has, in recent decades, been widely planted even in conservation areas, such as Cajas National Park where first generation hybrids with all four native species can now be seen ( Caiza et al. 2021). We strongly argue against using this species for afforestation projects.

Notes.

Polylepis racemosa can be distinguished from the most similar species P. acomayensis by having larger leaflets (2.3-3.9 × 0.7-1.5 cm versus 1.6-2.3 × 0.5-0.9 cm), serrate versus crenate leaflet margins, tomentose, 0.4-2.0 mm long versus villous, 0.9-1.1 mm long hairs on the lower leaflet surfaces, inflorescences 4.2-11.7 cm with 7-21 flowers versus 2.0-4.0 cm with 5-7 flowers and 9-19 versus 19-25 stamens. Occasionally, specimens of P. racemosa resemble those of P. triacontandra in having the same number of lateral leaflet pairs and same lower leaflet surface hair type (tomentose), but it differs in leaflet margin (serrate versus crenate), leaflet apices (round versus acute to revolute), lower leaflet surface hair length (0.4-2.0 mm versus 0.4-0.8 mm), number of flowers per inflorescence (7-21 versus 11-13) and number of stamens (9-19 versus 21-23).

Polylepis racemosa is the taxonomically most enigmatic species of the genus. No natural populations are known, but it is very fast growing and the most commonly cultivated species of the genus. Various ploidy levels have been documented in the species, with tetra- and octoploids dominating, but there are also indications of diploids and aneuploids (Fig. 87 ). We recognize three distinct morphotypes in this species: type A from Ecuador and northern Peru with leaflets 2.9-3.6 × 0.9-1.2 cm and lower leaflet surfaces densely tomentose with 1.5-2.0 mm long hairs (Fig. 85E, F ), type B mostly from central Peru with leaflets 2.3-2.9.0 × 0.8-0.9 cm and lower leaflet surfaces sparsely tomentose with 0.8-1.1 mm long hairs (Fig. 85C, D ) and type C mostly from southern Peru with leaflets 3.1-3.9 × 1.2-1.5 cm and lower leaflet surfaces sparsely tomentose with 0.4-0.5 mm long hairs (Fig. 85I, J ).

We hypothesize that P. racemosa is a species of hybridogenic origin that had already been adopted by prehispanic Andean inhabitants because of its fast growth. It is unknown whether the original hybrid or hybrids originated naturally or because the parent species were cultivated in close proximity, as has been shown for species of Leucaena ( Leguminosae) in Mexico ( Hughes et al. 2007). Based on the relatively low ploidy level (tetra- and possibly diploids) and morphological intermediacy, we propose that type B may be closest to the ancestral hybrid and that P. fjeldsaoi or P. incana on the one hand and P. flavipila on the other hand are possible parent taxa. Once the species was widely cultivated, there probably were additional hybridization and polyploidization events, leading to the morphological and cytological variability seen today. Translocations of individuals between different human population centers would then lead to the complex present-day geographical distribution of the forms.

Specimens examined.

Ecuador. Azuay: Cuenca, carretera Molleturo, Naranjal , 3778 m, 21 August 2008, Romoleroux 5155 (QCA!) . Chimborazo: Riobamba, Parroquia Licto, comuna Molobog , vía Riobamba-Licto , 01°46'S, 078°36'W, 2900 m, 30 November 2004, Caranqui 1303 (CHEP) . Pichincha: Cayambe, Parroquia El Quinche, comunidad Chumillos , sitio arqueológico Quito Loma , a 10 km al este de El Quinche, 00°06'16"S, 078°12'43"W, 3650 m, 26 August 2009, Asanza 2088 (QCNE). Papallacta, Papallacta along track from Termas de Papallacta to entrance of Cayambe-Coca NP, 00°21'33"S, 078°08'58"W, 3350 m, 04 July 2014, Kessler 14608 (Z!) .

Peru. Ancash: Casma, El Tambo, 3600 m, 25 August 1978, Mostacero 531 (MO!). Huaraz, Quebrada Quillcayhuanca, 3620 m, 30 October 1989, Arce 161 (MO!); Q. Quillcayhuanca, 3650 m, 30 October 1989, Arce 164 (MO!); en vivero forestal de Yanama, procedencia: Qilllcayhuanca, 15 December 1989, Arce 183 (MO!); Yupa, E of Huaraz on road to Pitec, agricultural land, trees along edge of fields, 09°31'S, 077°28'W, 3700 m, 22 May 1985, Smith 10701 (AAU!, MO!, QCA!, USM!); just below the summit of Huaraz-Casma road, 09°33'S, 077°34'W, 3900 m, 05 June 1985, Smith 10846 (MO!, USM!); plants purchased in the weekly herb market, the Thursday market, 09°31'S, 077°31'W, 4500 m, 05 June 1986, Smith 12449 (MO!). Huari, en vivero forestal de Yanama, procedencia: Sapsha, en el Dist. de Chacas, 15 December 1989, Arce 184 (MO!). Independencia, Pitec, Coordillera Blanca, 09°30'S, 077°30'W, 3800 m, 11 August 1988, Frimer 10 (AAU!). Recuay, Cátac, cerca a Querococha, 09°42'57"S, 077°18'45"W, 4185 m, 08 November 2014, Boza & Urquiaga 3020 (USM!, Z!); Laguna Querococha, 09°40'33"S, 077°19'54"W, 4000-4100 m, 11 June 2002, Cano 12412 (MO!, USM!); Dist. Marca, 3600 m, 13 June 1998, Gamarra 816 (USM!); Conococha-Pativilca, near Puente Santa Rosa, roadside slope, 4000 m, 16 August 2002, Schmidt-Lebuhn 520 (GOET!, USM!); Huascarán National Park, sector Querococha, alluvial fan at W end of lake, 09°44'S, 077°20'W, 3950-4080 m, 05 July 1985, Smith 11076 (MO!, USM!). San Marcos, the town of Chavin, Cordillera Blanca, 09°35'S, 077°10'W, 3150 m, 02 October 1988, Frimer 116 (AAU!); the town of Chavin, Cordillera Blanca, 09°35'S, 077°10'W, 3150 m, 02 October 1988, Nielsen 116 (AAU!). Ticapampa, Cord. Blanca Western end of Lag. Querococha, on road between Huaraz and Chavín, western side of pass, 09°42'S, 077°20'W, 4000 m, 17 February 1987, Boertmann 71 (AAU!, QCA!). from Huaraz towards Casma, 3500 m, 04 April 1988, Renvoize 5052 (AAU!). Apurimac: Andahuaylas, Dist. Pampachiri, 3700 m, 01 January 2004, Vargas 186 (USM!). Carhuacahua, Pacachacas Valley, 3200 m, 07 November 1935, West 3787 (MO!). Ayacucho: Huamanga, Quinua, centro urbano de Quinua, 3250 m, 01 May 2013, Hurtado JAHH030 (USM!); Dist. de Quinua, centro urbano de Quinua, 3270 m, 01 May 2013, Hurtado JAHH031 (USM!); Dist. Acocro; alrededor de Juiza, 09 April 2002, Vargas 103 (USM!). La Mar, Laguna de Toctococha, 12°58'09"S, 074°00'00"W, 4200 m, 30 September 2003, Mendoza 1015 (MO!); Aypacorral, camino a Uras. Dist San Miguel, 3100-3180 m, 04 April 2005, Roque 4717 (USM!); Dist. Luis Carranza, alrededor de Sacsamarca, 22 February 2001, Vargas 58 (USM!); Dist. Luis Carraza, alrededor de Sacsamarca, 22 February 2001, Vargas 59 (USM!). Vilcas Huaman, Dist. Vilcashuaman, Cerro Anahuarje subiendo por Allaspina y Churiaccaza, 3800 m, 27 September 2004, Baldeón 6141 (USM!); Dist. Vilcashuaman, Qapap Ñan (Camino Inca) por Viscachayoc, 13°39'18"S, 073°56'13"W, 3650-3680 m, 29 September 2004, Baldeón 6159 (USM!); cerca del puente Rumichaca II, en la carretera Los Libertadores, Dist. Pilpichaca, 26 June 2001, Roque 3328 (USM!). Cajamarca: Celendin, Celendin-Cajamarca km 28, cultivated as field border post, 08 August 2002, Schmidt-Lebuhn 490 (GOET!, USM!); Celendin-Cajamarca rd, 27-40 km from Celendin, 07°02'S, 078°14'W, 3200-3400 m, 25 February 1984, Smith 6247 (MO!, UMO, USM!). Encañada, Pampa del Toro on the road between Cajamarca and Celendin, 07°02'S, 078°16'W, 3400 m, 15 February 1987, Brandbyge 99 (AAU!). Hualgayoc, Hualgayoc, 06°53'16"S, 078°40'05"W, 3683 m, 31 May 2015, Boza & Urquiaga 3008; 3118; 3119 (USM!, Z!); Chugur, sobre la ruta a Perlamayo, 2950-3000 m, 20 March 1988, Sánchez 4679 (AAU!). Magdalena, near Cumbe Mayo, 07°11'S, 078°35'W, 3500-3650 m, 26 January 2003, Lægaard 22233 (AAU!). San Marcos, Bajada de la Totorilla, siguiendo el curso del Río Shitmalca, 3550 m, 31 October 1992, Sánchez 6412 (F!, QCA!). San Miguel, Cajamarca-Bambamarca road, about 60 km from Cajamarca, 06°50'S, 078°40'W, 3800 m, 17 February 1983, Smith 3499 (F!, MO!, USM!). San Pablo, Tumbaden, camino a Vista Alegre, entre la escuela de Antevo y Vista Alegre, 06°58'15"S, 078°42'59"W, 3300 m, 15 January 2004, Sánchez 12517 (US!), 2687 m, August 1802, Humboldt 3685 (B, F!, MO!); Cajamarca to Bambamarca, side road to Chugur (95 km from Cajamarca), 20 March 1988, Renvoize 4846 (AAU!); Micuypampa, 66 km from Cajamarca towards Celendin, 3450 m, 26 1988, Renvoize 4951 (AAU!); Cumbe Mayo. 16 km from Cajamarca, 3500 m, 27 March 1988, Renvoize 4980 (AAU!); entre Cajamarca y Cumbe Mayo, km 13, 3200 m, 11 June 1990, Sánchez 5322 (F!). Cusco: Cusco Sacsayhuaman, 13°30'35"S, 071°58'43"W, 3391 m, 11 June 2015, Boza & Urquiaga 3030 (USM!, Z!); Cusco Tambomachay, 13°30'35"S, 071°58'43"W, 3550 m, 11 June 2015, Boza & Urquiaga 3031 (USM!, Z!); Dist. Cusco, Chacan, 13°30'06"S, 071°59'03"W, 3500-3600 m, 21 March 2003, Calatayud 1247 (CUZ!, F!, MO!); 100m von FuSptad nach Sacsayhuaman, 3600 m, 20 August 1989, Kessler 391 (GOET!, Z!); Sacsayhuaman, 3600 m, 07 July 1999, Lægaard 20465 (AAU!); Chacan S of Cusco, 13°29'S, 072°00'W, 3900 m, 10 February 2003, Lægaard 22351 (AAU!); 22352 (AAU!); cultivated on the Plaza de Armas, 13°32'S, 071°59'W, 3400 m, 16 August 2000, Schmidt-Lebuhn 39 (GOET!); cultivated on the Plaza de Armas, 13°32'S, 071°59'W, 3400 m, 22 August 2000, Schmidt-Lebuhn 40 (GOET!); Calca, Taray Chitapampa, a 16 km de Cusco en la carretera Cusco-Urubamba, 3500 m, 16 May 1987, Núñez 8117 (MO!, USM!). Chumbivilcas, Río de Velille, 3850 m, 18 December 1962, Vargas 14090 (CUZ!). Cusco, C’orao, 3653 m, 01 May 2003, Arce s.n (USM!); Miskahuara (margenes del río), 3300 m, 01 February 1970, Vargas 21978 (CUZ!); Pumamarca, 3400 m, 11 May 1946, Vargas 6044 (CUZ!). Espinar, Yauri Virginniyoc, ca. 35 km de Yauri, camino de Yauri, puente viejo, Maucallacta hacia Suicutambo, por carretera y caminos de Herradura, 4100 m, 13 April 1987, Núñez 7889 (MO!, USM!). Urubamba, Chicon, 3517 m, 01 April 2003, Arce s.n (CUZ!); Chincheros, around community of Taucca, 13°25'S, 072°00'W, 4050 m, 14 January 1982, Davis 1578 (A!, USM!); Tankarpata, above Cusco airport, valley between dry steep hillsides, 13°31'S, 071°58'W, 3500 m, 23 July 1983, Gentry 43217 (F!, MO!, USM!); Dist. Huayllabamba, entre Huayoccari y las lagunas de Yanacocha y Kellococha, 13°13'S, 072°16'W, 2900-4600 m, 17 July 1989 - 18 July 1989, Tupayachi 1139 (MO!); Dist. Huayllabamba, Quebrada de Huayoccari-Laguna de Yanaccocha, 13°21'15"S, 072°03'55"W, 2900-3860 m, 21 December 1988, Tupayachi 808 (MO!). 3300-3800 m, 19-21 May 1958, Humbert 1958 (US!); San Sebastián, 25 March 1988, Velásquez 12 (MO!). Huánuco: Huamalies, 17.5 km N of Llata by Singa, 09°23'S, 076°52'W, 3600 m, 16 September 1965, Bird 1383 (MO!), Lauricocha, Jesus, río Lauricocha, ladera, Dist. San Miguel de Cauri, 3326 m, 08 August 2003, Salvador 541a (USM!). Junín: Huancayo, Concepción, 20 September 1982, Aguilar s.n (USM!); Pampas Valley, 3300 m, 24 May 1948, Anderson 695 (US!); Chongos al sur de Huancayo, 3500 m, 24 March 1983, Castañeda s.n (USM!); Cerca a Huancayo, 3800 m, 01 July 1957, Ferreyra 12418 (MO!, USM!); 3400 m, 03 December 1960, Kunkel 5626 (GOET!); Huayucachi, 3260 m, 05 January 1974, Rosales 5 (USM!); 3317 m, 01 March 1945, Soukup 2720 (F!); Quilcas, alrededores de Shuckto-Loma, 3500 m, 09 January 1994, Yarupaitán 1154 (USM!). Jauja, Common along at stream in sheltered valley east of Concepcion; foliage bluish-green, 3500 m, 09 January 1945, Hodge 6221 (A!, US!); Quinual Dist. Mito, 3295 m, 14 August 1974, Rosales s.n (USM!). Junín, collected near Chongos Bajo, 3300 m, 19 February 1974, Antunez de Mayolo 18 (USM!); Tarma, Huacapo near Tarma, 11°25'S, 075°42'W, 4030 m, 01 February 1987, Boertmann 13 (AAU!); Cerca a cumbre entre Tarma y Oroya, 3500-3600 m, 29 June 1948, Ferreyra 3792 (MO!, US!, USM!); Casa Blanca cerca de Tarma verdosas, 3300-3350 m, 08 April 1952, Ferreyra 8259 (MO!, USM!); along shaded stream bank, 3000-3200 m, 20-22 April 1929, Killip 21899 (A!, F!, US!); Palcamayo, 3000 m, 09 March 1960, Kunkel 4439 (GOET!); 6 km north of Jauja on the road to Tarma, 07 January 1977, Simpson 8544 (USM!). Yauli, La Oroya, 11°32'S, 075°53'W, 3700 m, 07 January 1983, Smith 2973 (MO!, USM!), between La Quinua and Huariaca, Estancia La Aurora, rivershore, 3300 m, 24 June 1940, Asplund 11944 (US!); Ataura, cerca Jauja, Mucha s.n (MO!, USM!); Runatullo, 3500 m, 01 July 1940, Ridoutt 11775 (USM!); Tingopacha along a stream runing through the village, 07 January 1977, Simpson 8543 (US!, USM!); Km 72 along 3-S from Jauja to La Oroya, 4 km south of Parco along the fence of a house, 09 January 1977, Simpson 8549 (US!, USM!); North of Junin near a house along the road, 11 January 1977, Simpson 8556 (USM!); Palca, 01 August 1947, Soukup 3498 (F!). La Libertad: Otuzco, Ruta Salpo-Samne, 3200 m, 27 May 1993, Leiva 741 (MO!, QCA!). Sanchez Carrion, Trujillo-Huamachuco road, about 10 km W of Huamachuco, 07°50'S, 078°15'W, 3400 m, 14 February 1983, Smith 3354 (MO!, USM!). Santiago de Chuco, Quiruvilca, margen derecha del río Chuyunhual, 3620 m, 02 May 2003, Cano 13106 (USM!); 13110 (USM!); Dist. Quiruvilca. El Sauco, 3605 m, 16 June 2013, Gonzáles 2286 (USM!); Los Quinuales (al norte de Quiruvilca), 3775 m, 24 March 1994, Leiva 1090 (F!, QCA!); Sauca (Santiago de Chuco), 3300 m, 16 June 1984, Sagástegui 11941 (MO!). Trujillo, purchased in the Mayorista Market. Medicinal plant area, 08°07'S, 079°01'W, 12 January 2010, Meyer 881 (MO!); purchased at Mercado Mayorista, 08°07'S, 079°01'W, 23 June 2008, Rothrock 3 (MO!). Lima: Canta, Lachaqui, 05 October 1989, Arce 101 (MO!); Lachaqui, camino al cerro Llamarume, 3850 m, 11 September 1991, Vilcapoma 1202 (USM!). Chicla, Chicla on Route 20 from Lima to La Oroya, 12 January 1977, Simpson 8560 (A!, MO!, USM!). Huarochiri, Carampoma, 3876 m, 18 November 1989, Arce 167 (MO!); Vista Alegre, Río Blanco, 3600 m, 21 February 1990, Arce 204 (MO!); San Juan de Tantaracnche, 3500 m, 22 March 1990, Arce 207 (MO!). Oyon, Oyon, 3600-3700 m, 25 June 2000, Cano 10818 (USM!); Cacray towards la Oroya, Weberbauer 220 (F!). Pasco: Pasco, La Quinua, 3540 m, 01 December 1986, Rivas s.n (USM!); between Huanuco and Pampayacu, eastern side, 3657 m, 04 February 1927, Kanehira 5 (A!, F!). 1839-1840, Gay s.n (USM!); San Buena Ventura, Née s.n (F!); 1778-1788, Rodríguez s.n (F!); 1779-1854, Ruiz s.n (G, MO!); entre Tarma y Oroya a 10 km de Tarma, 3600-3700 m, 30 June 1954, Tovar 2371 (MO!).

Figures

Figure 85. Polylepis racemosa Ruiz & Pav A flowering branch B flowers C lower leaflet surface D upper leaflet surface E lower leaflet surface F upper leaflet surface G stipule sheaths H bark I lower leaflet surface J upper leaflet surface (A, B, H-J Boza & Urquiaga 3030. Cusco C, D Boza & Urquiaga 3020. Ancash E-G Boza & Urquiaga 3118 Cajamarca). Scale bars: 1 cm (A, C-F, I-J); 5 mm (B); 2 mm (G). Photographs by E. G. Urquiaga F.

Figure 86. Polylepis racemosa Ruiz & Pav A flowering branch B stipular sheaths C fruit D lower leaf surface E upper leaf surface (A, C Vargas 186 B, E Vargas 59 D Vargas 58). Scale bars: 4 cm (A); 10 mm (C); 3 cm (D, E). Photographs by T. E. Boza E.

Figure 87. Geographical distribution of the ploidy levels in Polylepis racemosa. Pie chart sizes represent number of individuals studied: 1, 2, 3,> 5 indiv.

Figure 92. Geographical distribution of the species of subsection Polylepis Racemosae Racemosae.