Iochroma amicorum M. Cueva, S. D. Sm. & S. Leiva, 2015

Manchego, Marco Antonio Cueva, Smith, Stacey Dewitt & Gonzáles, Segundo Leiva, 2015, A new and endangered species of Iochroma (Solanaceae) from the cloud forests of central Peru and its phylogenetic position in Iochrominae, Phytotaxa 227 (2), pp. 147-157 : 149-152

Iochroma amicorum M. Cueva, S. D. Sm. & S. Leiva spec. nov. ( Fig. 1 , 2 )

Type :— PERÚ. Oxapampa : Distrito de Huancabamba , sector Oso Playa, Parque Nacional Yanachaga-Chemillén, camino hacia el campamento, 2362 m, 10° 19 ′ 27 ʺ S 75° 35 ′ 20 ʺ W, 15 Octubre 2009, M. Cueva, A. Monteagudo, L. Valenzuela, A. Peña, J. Mateo & R. Rivera 646 (holotype: HOXA!; isotypes: MO!, USM!, HUT!, HUSA!, HSP!) .

Iochroma amicorum can be distinguished from the most similar Iochroma species ( I. umbellatum and I. tingoanum ) by its funnel-shaped to campanulate corolla, its staminal filaments inserted in the basal part of the corolla tube to form a visible stapet with small lateral extensions joined to the corolla tissue, and its mature globular fruits, usually white with a purple base.

Shrub or small tree, 2–5 m high.Stem cylindrical, older parts of creamy colour, glabrous and with lenticels white-yellowish or brownish, the main trunk with a diameter of 3–5.5 cm, old branches with a diameter of 0.9–1.5 cm; young stems dark green or creamy green with a diameter of 3.5–7 mm, puberulent, internodes 0.5–2 cm, the indumenta appressed along the surface of the stem, with simple and branched whitish hairs. Leaves simple, entire, 17–32 × 5.5–10.1 cm, elliptic or narrow elliptic, membranaceous, apex generally acuminate or sometimes acute, base attenuate, with primary venation pinnate, prominent on the abaxial surface, 19–27 secondary veins uniformly spaced born approximately at right angles from the midrib; adaxial surface glabrescent dark green, with simple and branched hairs generally appressed to the lamina’s surface; abaxial surface light green, densely pubescent, with whitish hairs simple and branched, more or less erect or curled, iridescent, 0.5–1.5 mm long; petioles 2–4 cm long, puberulent, with similar hairs to the ones present in the lamina. Flowers 2–10 arranged in fascicles on short shoots of 0.5–5 cm long, simulating umbels; pedicels green and puberulent at anthesis, 16–45 mm long, with a diameter of 1.5 mm expanding up to 3.5 mm beneath the calyx; flower buds ovoid or oblong protruding from the calyx tube. Calyx 4–6 mm x 6.5–9.5 mm, cupulate to urceolate, thick, green turning white towards its apical border, truncate with short rounded uneven lobes or obtuse, external surface puberulent with protruding venation, internal surface smooth with minute papillae scattered. Corolla 11–19 mm × 6–8 mm, campanulate to funnel-shaped, slightly thick or membranaceous, limb 12–21 mm in diameter at the anthesis, generally lilac or purple fading to white at the base, with 5 green to purple maculae in its interior, rarely completely white with green maculae, puberulent in its exterior, with simple hairs whitish, glabrous internally, lobes of 4–4.5 mm × 5 mm, deltoid short, apex acute, extended or slightly reflexed, puberulent in both surfaces. Stamens equal, inserted 2 mm from the basal edge of corolla tube, free portion of filaments 5.5 mm long and with a diameter of 0.5–1 mm, glabrous, white, filament base abruptly widening at the insertion zone with the corolla, forming a visible stapet that develops two small lateral extensions which are not free, anthers 3–3.5 × 1.5–2 mm, oblong, creamy white. Gynoecium 3–3.5 × 3 mm with globose, glabrous ovary; style 6 × 0.8 mm towards the base, with a diameter of 1.5–1.8 mm towards the apex, claviform, white, glabrous; stigma 0.6 × 2 mm, expanded, bilobed, green, papillose. Fruit 12–14 × 14–15 mm, a globose berry, slightly compressed apically, smooth, usually white with purple base, occasionally entirely white or entirely purple, coriaceous pericarp with sclerosomes, and well-developed placenta tissue. Fruiting calyx 7–8 × 13.5–14 mm, persistent, accrescent, truncate, with an irregular border. Fruiting pedicels 30–50 mm × 2 mm near the base, expanding up to 4 mm in diameter underneath the calyx. Seeds 150–178 per fruit, 1.5 × 1 mm, brownish flattened reniform, testa foveolate.

Etymology: —the specific epithet comes from the Latin amicus. The species is dedicated to the generosity of friends and botanical colleagues who assisted with the discovery and description of this new species by donating their time and energy to help the authors conduct this research. These parties are listed in acknowledgements.

Distribution and habitat:— I. amicorum is one of only two Iochroma species of the genus that extends south to 10°S latitude in central Peru. At present it is known from the province of Oxapampa, in the districts of Oxapampa and Huancabamba, Oso Playa, Milpo and San Alberto sectors inside Yanachaga-Chemillén National Park and in other adjacent zones ( Figure 3 ). It grows in cloud forests between 2300–2600 m. The majority of individuals of this riparian species grow in lightly disturbed or open areas along riverbanks or small streams. Occasionally, they are found in the shade of primary forest but still always adjacent to moving water.

Phenology:—This species’ phenology appears variable. In October 2009, the individuals in Sector Oso Playa were either flowering or in a fruiting state. In the same month in 2013 the majority of individuals at this site were vegetative and only a few possessed flowers or fruits. Other individuals collected at the Sector San Alberto in April 2009 had flowers and fruits whereas in October 2013 only vegetative plants were found. A return trip in March 2014 revealed only plants in a vegetative state at Sector San Alberto but fruiting individuals at Sector Oso Playa and Sector Milpo. Thus, it appears that I. amicorum flowers sporadically February through April and perhaps again September through October.

Conservation status:—According to the IUCN (2012) categories, I. amicorum is considered endangered (EN) following the B1ab (i, iii) criteria. This species is only known in four localities and its present range is approximately 220.9 km 2. The known populations are mostly in the buffer zone of Yanachaga-Chemillen National Park or outside the strictly protected area. In these areas, settlers are actively clearing land for agriculture and livestock breeding. In the future, these human activities could reduce the available riparian habitat for I. amicorum and/or eliminate some of its few known populations.

Additional specimens examined:— PERÚ. Oxapampa : Distrito de Oxapampa , Parque Nacional Yanachaga-Chemillén, Sector San Alberto, alrededores del Refugio el Cedro, 2483 m, 10º 32 ′ 43,3 ʺ S 75º 21 ′ 29,5 ʺ W, 26–27 Abril 2009, M. Cueva & R. Rivera 620 ( HOXA, USM, MO, HUT, HUSA) ; Camino Refugio el Cedro-Abra Esperanza, 2528 m, 10º 32’ 45.5”S 75º 21’ 26.2”W, 21 Octubre 2013, S. Smith et al. 551 ( HOXA, MO) ; carretera nueva Oxapampa- Bosque Shollet-Villa Rica , 2324 m, 10º 39’ 51.2”S 75º 19’ 2.4”W, 25 Octubre 2013, S. Smith et al. 571 ( HOXA, MO, USM) ; Distrito de Huancabamba , Parque Nacional Yanachaga-Chemillen, Sector Oso Playa, path to the camping area, 2362 m, 10º 19’ 26.7”S 75º 35’ 27.9”W, 20 Octubre 2013, S. Smith et al. 542 ( HOXA, MO, USM, HAO) ; path to the camping area, 2362 m, 10º 19’ 26.9”S 75º 35’ 24”W, 20 Octubre 2013, S. Smith et al. 543 ( HOXA, MO) ; path to the camping area, 2362 m, 10º 19’ 26.9”S 75º 35’ 24”W, 20 Octubre 2013, S. Smith et al. 544 ( HOXA, MO) ; camino Lanturachi-Cueva Blanca-Milpo , 2546 m, 10º 22’ 3.7”S 75º 36’ 25.4”W, 24 Octubre 2013, S. Smith et al.563, ( HOXA, MO, USM) .

Figures

FIGURE 1. Iochroma amicorum. A. Flowering branch. B. Inflorescence. C. Fruits. D. Corolla atanthesis. From M. Cueva et al. 646. E. Individual with white flowers. From M. Cueva & R. Rivera 620 (photo by Antonio Peña (A), Abel Monteagudo (B), and Marco Cueva (C–E)).

FIGURE 2. Iochrom aamicorum.A.Fruit.B.Flower.C.Antherlateral view.D.Seed.E. Gynoecium.F. Floweringbranch.G.Inflorescence. H. Anther dorsal view. I. Open corolla. J. Stamen isolated, showing anther in ventral view, and stapet with lateral projections which was separated from the tissue of the corolla. From M. Cueva et al. 646. Drawing by Segundo Leiva.

FIGURE 3. Distribution of I. amicorum. (PNYCH= Yanachaga-Chemillén National Park. ZA= Buffer Zone. RCY= Communal Reserve Yanesha. BPSMSC= Protected Forest of San Matias-San Carlos).