Quad. Bot. Ambientale Appl., 30 (2019): 33-39. Pubblicato online: 24/04/2020 http://www.centroplantapalermo.org/ Taxonomic studies on the genus Islaya (Cactaceae): Islaya camanaensis, a new endemic species from Arequipa region (Peru) †F. CáCeres de Baldárrago1, F.M. raiMondo2, i. PoMa2 & P. Mazzola2 1Herbarium arequipense HUsa. laboratorio de Botánica. dpto. de Biología, Facultad de Ciencias Biológicas. Universidad nacional de san agustín. arequipa, Peru. 2PLANTA/Centro mediterraneo di ricerca, documentazione e Formazione, Via serraglio Vecchio 28 i - 90123 Palermo. [email protected] aBstraCt.–in the context of a research project on cactaceae family of the southern region of Peru, a population of the genus Islaya was particularly critical. the taxonomic study carried allowed to describe a new species called Islaya camanaensis whith reference to the province of Camaná where it occurs between 900 and 1050 m a.s.l.. such species shows clear taxonomic differences from the other Islaya species occurring in Peru, as far as root and stem; ribs, areolas, lilac flowers, fruits and seeds are concerned. the species, which is soli- tary in its habitat, blooms in september and bears fruits in november december. an average of 7 individuals in 100 m2 were evaluated in a transect of 50 km. its main threat are the roads and concession in areas that have been delivered to expand agriculture and housing. Key words: succulent plants, endemic flora, Perù, Camaná province. introdUCtion in turn transferred to several other genera such as Echinocactus, Malacocarpus, Neoporteria and then to the present work is part of a study on the Cactaceae of Eriosyce. Besides, all the former species of Islaya were inclu- southern Peru, which has been running for several years. as a ded by KatterMan (1994) in a single specific taxon, Eriosyce background, several studies have already been carried out on islayensis (Forster) Katterman together with 10 other Chilean the cactaceae of the arequipa region, especially in the andean genera. the same treatment was made by anderson (2001). highlands, but very few investigations have been made on the cactaceas that live in the hills, valleys and ravines of the coast nevertheless, on the basis of a comprehensive anatomical and of arequipa. in the last five years studies began in the coast of systematic study of the genus Eriosyce (including the Peruvian arequipa, especially in arid hills, with rather scarce results species), nyFFeler & eggli (1997) stated that the populations because the cacti of these areas were always in a vegetative occurring along the coasts of Peru do not belong to Eriosyce, state. all winters and springs these lomas were visited, but the but to another genus. taking into account this work, ostolaza results were always the same. However from June 2013 to (2014) referred such populations to Islaya Backeb. and propo- december 2014 in the coast of the province of islay and sed a larger revision of this genus, especially for the Peruvian Camaná intense rains began on the hills and also in the ravines populations. these studies are still in progress from both the between 800 and 1200 m a.s.l. in the completely arid pampas. bio-systematic and conservation points of view. therefore, while rains persisted, up to 2014, important excur- according to BaCKeBerg (1958-1962) and ritter (1964) sions and large plant collections were made between 200 and the genus Islaya includes globular to shortly cylindrical plants 1050 m a.s.l.. other explorations were later extended above with very woolly apex, yellow, apical small flowers, shortly 1050 m a.s.l., especially in the pampas of the toro gully, and conical floral tube with wool and bristles; fruit red, elongated some areas that have been given in concession for irrigation. with hairs and floral remains, hollow at the base, with the black during the spring time the cacti were found in flower. this seeds in a carpelar dehiscent sac at its base. allowed to carry out a bio-systematic study of the cactáceas only two Islaya species and one subspecies were so far and beside to verifie their state of conservation. in the province of Camaná above 500 m a.s.l. Cleistocactus known from Peru: Islaya islayensis (Forster) Backeb. subsp sextonianus, Haageocereus decumbens, occur. this paper islayensis, Islaya islayensis subsp grandis (rauh & Backeb.) deals with the results of some studies carried out on Islaya that g. Charles and Islaya omasensis ostolaza et Mischler that has in such area occurs under 500 m a.s.l.. been described very recently (ostolaza 2014). in addition, a this genus was described in 1934 by BaCKeBerg, which new endemic species is here described and called Islaya cama- referred its name to the province of islay in the arequipa naensis Cáceres, with reference to the name of the Province of region. the species formerly included there were afterwards Camaná where it occurs in the department of arequipa. taxonoMy the areola and 4-5 central spines 5-7 mm long, extended towards the sides. Flowers sessile with diploclamide peri- Islaya camanaensis Cáceres sp. nov. (Figs. 1, 2 & 3) gon, with numerous dark lilac to purple tepals 3.8-4×2.5- 2.8 cm in the floral tube and 3.5 cm in the anthesis. tepals Diagnosis intense pale to dark lilac, not reddisch. dense woolly hypanthium, covering up to the half of tepals, 1.2×0.8 in small plant 5-10 cm high. it bears 18 straight or spiraled the middle and 0.5-1×1.5 cm in the apical part. Bracts uniform ribs; oval areolas margined by two rows of short slightly subulate, 1.5-3 mm with areolas of 2 mm and abun- spines; spines 8-10, 1-2 mm long; central spines 4, 2-3 mm dant whitish wool, that remains on the fruit until after ripe; long, greyish green. Parenchyma and inner medulla reddish, bristles reddish, abundant at the base of tepals. Calyx-like about 2 cm. Flowers with calyx-like tepals dark lilac; corol- tepals subulate, dark lilac 3-5 1.5-2.5 mm in 2-3 series, la-like tepals lilac purple to light lilac. staminal filament hardly distinguishable by dense wool. Corolla-like tepals thin; anthers intense yellow. ovary rounded to short ovoid; numerous, obovate with acute apex, slightly mucronate short cylindrical style 10-12×2.5 mm. stigmas 10-12, wide, with a dark central stain along the tepalo, 2.8-3.2×0.6 cm, oblanceolate, whitish, 4-5×1.2. small fruits 0.5-1 cm, cove- light to dark lilac, not reddish. stamens numerous; fila- red by abundant whitish wool with persistent and abundant ments cylindrical shorter than the stigma, withish; anthers red bristles, and floral coverings. seeds 6-10 kidney-shaped; distichous intense yellow, 1 × 1-2 mm. ovary rounded to outer coat blackish and shiny. the new species differs from ovoid, ovules ovoid clear cylindrical; style 10-12×2.5 mm; both Islaya islayensis (Forster) Backeb. and Islaya divari- stigma 10-12 numerous 4-5×1.2 mm, whitish. Fruit: catiflora ritter. slightly rounded ovoid 0.8-1 cm, dark lilac; areolas 1 mm, woolly, dehiscent by the base; cover by numerous whitish hairs and dense red bristles remaining until after the fruit is Type ripe. seeds 6-10, reniform 2×1.5 mm; testa shiny black, hilum whitish. Perú. departamento de arequipa. Pampas de samuel Pastor. Provincia de Camaná. 900 m a.s.l. 14 de octubre del 2013. Cáceres & Baldárrago, nro 7323 (Holo, HUsa). Habitat the species occurs only in the loose and marlestone soils of Description the pampas in sandy, crusty, desertic soils from 900 to 1050 m a.s.l. (Fig. 8). the stems grow buried in the soil when are in a small cactus 5-10 cm high, half or almost all buried, vegetative state or, in some cases, stand out to the middle. it can rounded to ovoid, compressed apically (Fig. 1), green-gra- only be observed when very showy flowers are produced. yish. roots dichotomously branched, 15 cm long (Fig. 3a). stem: succulent, ovoid 5-10×(4)-7 cm. areolas 3-4 mm, oval with two marginal rows of short spines; 8-10 short spi- Associated vegetation nes 1-2 mm long; 4 central spines 2-3 mm long. Very dense woolly reddish bristles on the apical part of the stem; gra- on the slopes and pampas, that are completely desertic, only yish green colour. Parenchyma reddish; medulla 2 cm in Haageocereus decumbens in very few specimens occurs; in diameter, reddish. ribs 16-18 straight or spirally twisted; some other places towards the pampas Tyllandsia purpurea is ribs 0.5 cm distant and hight, parenchyma reddish, cortical found. medulla 2 cm, reddish. spines 10-12 in two series, the mar- ginal 6-7 almost homogeneous 5 mm long at the border of Fig. 1 - Islaya camanaensis: stem showing ribs and areolas. Fig. 2 - Purple red flowers of Islaya camanaensis in hillside habitat. 34 Fig. 3 - Islaya camanaensis: a, habit; B, areole and spines; C, flower; d, vertical section of flower; e, style and stygmata; F, corolla-like tepal; g, calyx-like tepal; H, hypanthium bract; i, fruit; J, seed. 35 Fig. 4 - Islaya camanaensis in the field. the upper part only is Fig. 5 - details of Islaya camanaensis: a) dichotomously branched visible, most of the body being buried. roots, up to 15 cm long; b) fruit with the apical part with wool and reddish bristles. Distribution recorded only from la Pampa, upper part of the gorge, between 800 and 1050 m a.s.l., Islaya camanaensis is endemic to an area of about 50 km2 in the province of Camaná, department of arequipa (Fig.