Heisteria austroecuadorica (Erythropalaceae): A new species from southeastern Ecuador Author Cornejo, Xavier 0000-0002-4081-4047 Herbario GUAY, Departamento de Botánica, Facultad de Ciencias Naturales, Universidad de Guayaquil, Av. Raúl Gómez Lince s. n. y Av. Juan Tanca Marengo (campus Mapasingue), Guayaquil, Ecuador & xcornejoguay @ gmail. com; https: // orcid. org / 0000 - 0002 - 4081 - 4047 xcornejoguay@gmail.com Author Homeier, Jürgen 0000-0001-5676-3267 Plant Ecology and Ecosystems Research, University of Goettingen, Goettingen, Germany & Faculty of Resource Management, HAWK University of Applied Sciences and Arts, Goettingen, Germany. & jhomeie @ gwdg. de; https: // orcid. org / 0000 - 0001 - 5676 - 3267 jhomeie@gwdg.de Author Ulloa, Carmen Ulloa 0000-0002-4081-4047 Missouri Botanical Garden, 4344 Shaw Blvd., Saint Louis, MO 63110, U. S. A. & carmen. ulloa @ mobot. org; https: // orcid. org / 0000 - 0002 - 4081 - 4047 carmen.ulloa@mobot.org text Phytotaxa 2023 2023-06-07 599 3 201 206 http://dx.doi.org/10.11646/phytotaxa.599.3.7 journal article 53693 10.11646/phytotaxa.599.3.7 c63d7d3e-8150-4e7e-bae2-bf85671d8fc4 1179-3163 8012611 Heisteria austroecuadorica Cornejo, Homeier & C. Ulloa sp. nov . ( Fig. 1 ). Diagnosis: — Species nova affinis Heisteria asplundii , a qua folia angusta, stamina decandra, calycem fructuum basin non occultans differt. Type: — ECUADOR . Zamora Chinchipe : area of the Reserva San Francisco , 3°58’S 79°04’W , 1980 m , 6 September 2005 (fl, fr), J. Homeier & S. Hänel 1609 ( holotype : GUAY!; isotypes: GOET!, LOJA !, QCNE-195572!). Description: — Tree , to 20 m tall and 30 cm DBH; milky white latex present in stems and branches; branches ca. 2 mm thick, terete, striate, glabrous. Leaves alternate; petiole 7–16 mm long, rugose, light- to dark-brown, channeled above, glabrous; lamina chartaceous, (4.5–)7–19 × 2–6 cm , elliptic-lanceolate to narrowly elliptic or narrowly lanceolate, apex acuminate to long-caudate, drip-tip 7–12 mm long, base cuneate, margins revolute, dull, smooth, and glabrous on both sides, venation brochidodromous, midrib slightly sulcate above, prominent below, secondary nerves 6 to 9 pairs, prominulous, tertiary venation inconspicuous. Inflorescence ramiflorous, a short axillary fascicle, 3 to 15 flowers per fascicle; bracts cucullate-deltoid, 0.5–1 × 0.5–1 mm , the apex obtuse to broadly obtuse; pedicel 5–7 mm long. Calyx patelliform or cup-shaped, 5-lobed, lobes ca. 0.5 mm long, triangular to broadly triangular, acute at apex, green. Petals 5, ca. 3 × 1 mm , free, densely papillose or shortly pilose on the adaxial side, greenish-white. Stamens 10, filaments ligulate, ca. 2 × 0.3 mm , the 5 inner ones ca. 1.8 mm , all free, anthers ca. 0.5 × 0.8 mm . Nectary absent; ovary oblatesubglobose ( in vivo ), pyriform ( in sicco ); style ca. 0.5 mm , stigma slightly 3-lobed. Fruiting pedicel 1.5–2.3 cm long, slightly swollen, 2–3 mm distally. Fruiting calyx slightly 5-lobed, 2.2–2.8 cm in diam., reflexed, stiffly chartaceous, orange to red, bright and shiny above, dull below. Drupe barrel-shape, olive green with maroon at apex ( in vivo ), 1.2–2 × 1–1.2 cm , rugulose, faintly ribbed longitudinally and tuberculate (from endocarp, in sicco ), with a clear, deep, circular depression at the apex. Etymology: —The epithet refers to the geographic pattern of distribution at southeastern Ecuador where the species occurs. Habitat and distribution: — Heisteria austroecuadorica is known from the San Francisco reserve, a forest remnant close to the settlement of El Líbano north of the Podocarpus National Park, and the Jamboe river basin in southeastern Ecuador , between 1000 to 2050 masl ; all three localities are on the Loja-Zamora road. The area is characterized by a rugged terrain and small-scale structural and floristic vegetation changes, which result mainly from the decreasing soil fertility along ravine-slope-ridge gradients (Werner & Homeier 2015). The newly described species is restricted to the ravines and lower slope positions with more fertile soils within the species-rich evergreen lower montane forests below 2050 masl , that reach up to 30 m height ( Homeier et al. 2008 , 2010). FIGURE 1 . Heisteria austroecuadorica Cornejo, Homeier & C. Ulloa. A, Inflorescence with flower buds. B, Terminal branchlet and immature fruits. C, Fruits surrounded at base by an accrescent persistent reddish-orange calyx. D, Pedicel and abaxial view of fruiting calyx. E, Abaxial view of a leafy branch and immature fruits. Photos by Jürgen Homeier, from the type population. In the ravines and on the lower slopes of this specific forest type , Heisteria austroecuadorica is accompanied by several tree species that have been described from this zone in the last years, stressing the biological importance of this area. Some examples are: Byrsonima homeieri Anderson (2007: 97) , Critoniopsis zamorensis Haro-Carrión & Robinson (2008: 17) , Meliosma longepedicellata Cornejo (2009: 93) , Magnolia zamorana Arroyo et al. (2013: 507) , Meriania franciscana Ulloa Ulloa & Homeier (2008: 383) , Naucleopsis francisci Berg & Homeier (2010: 197) , Ocotea homeieri van der Werff (2020: 210) and Quiina zamorensis Schneider & Zizka (2012: 265) . All of these aforementioned species have a narrow pattern of distribution that is restricted to the particularly diverse Amotape-Huancabamba zone ( Weigend 2002 , 2004 ), south of the Girón-Paute dry valley in southern Ecuador ( Jørgensen et al. 1999 ). With its relatively high-density wood ( 0.72 g /cm 3 ), large fruits and slow diameter growth rates, Heisteria austroecuadorica combines characteristics typical of a late successional tree species. Phenology: —Flowering was observed in June, September, October and December; fruiting material was collected in April, September and October. There are no existing observations on flower pollination or fruit dispersal. Conservation status: —This species is uncommon in the Reserva San Francisco: Homeier has only found a total of six trees (out of almost 4000) within three recently established one-hectare plots. At a second location, outside the Reserve, in El Líbano , only one tree has been seen. A third locality is represented by one collection only in the Jamboe river basin just further down at slightly lower elevation. Based on the very small area of occurrence ( 12 km 2 ), an extent of occurrence of 10.3 km 2 , the existence of only three localities, only one of which is protected within the private Reserva San Francisco, we assign a provisional category of Endangered (EN B2a(iv)), following the IUCN (2022) criteria. Paratypes : — Ecuador : Zamora Chinchipe : Reserva San Francisco , road Loja-Zamora , ca. 30 km from Loja, 3°58’S 79°04’W , 1800–2050 m , June 2005 (fl.), O. Cabrera & N. León 869 (HUTPL, fragm. in GUAY) ; same location, 1840 m , 20 October 2001 (fr.), J. Homeier 1025 ( LOJA , QCNE , MO , GOET ) ; same location, 1910 m , 11 September 2003 (sterile), J. Homeier & W. Quizhpe 1261 ( GOET , MO , QCNE ) ; same location, 1910 m , 20 October 2013 (fl.), J. Homeier 5098 ( HUTPL , QCA , GOET ) ; same location, 2040 m , 5 December 2016 (fl.), J. Homeier & J. Peña 5820 ( HUTPL , QCA , GOET ). Road Loja-Zamora , El Líbano , 4°5’S 78°59’W , 1720 m , April 2011 (fr.), J. Homeier , F.A. Werner & D. Cárate 4713 ( LOJA , QCA , QCNE , GOET ). Cuenca del río Jamboe , 4°08’S 78°56’W , 1000 m , September 1999 (fl, fr), W. Palacios 14881 ( MO ) . Discussion: —The fruits of Heisteria austroecuadorica are characterized by the apex presenting a circular depression, a key character in Sleumer’s treatment (1984) that is only found in three other species in tropical America: H. amphoricarpa Sleumer (1984: 49) , H. asplundii , and H. skutchii Sleumer (1984: 50) . Heisteria amphoricarpa , a Brazilian species, has a unique urn-shaped calyx enveloping most of the drupe and flowers with five stamens, while H. skutchii , a Costa Rican species with 10 stamens, has much wider, patent fruiting calyx (over 30 mm diameter). In Ecuador , the fruits of Heisteria austroecuadorica are relatively large with a depressed apex like those of H. asplundii , a tree endemic to northwestern Ecuador . However, H. austroecuadorica immediately differs from H. asplundii by its narrower leaves, with blades elliptic-lanceolate to narrowly elliptic or narrowly lanceolate, 2–6 cm wide ( versus leaves always with broadly elliptic blades, 10–15 cm wide in H. asplundii ), the flowers with 10 stamens ( vs. 5 stamens), the smaller fruiting calyx, up to 2.8 cm and covering just the base of the drupe ( vs. up to 4.8 cm and covering the basal 1/3 of the drupe); additionally, these two species are widely separated on opposite sides of the Andes mountains.