Croton condorensis Riina & Ceron 2014, sp. nov.
Creators: name: Riina, Ricarda
name: Vigo, Marco A.
name: Cerón, Carlos E.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Malpighiales
Euphorbiaceae
Croton
Croton condorensis

description: Croton condorensis Riina & Cerón, sp. nov. (Fig. 1)
The new species is similar to members of sect. Cyclostigma but it differs from these species in its narrowly ovate leaves, smooth seeds, and the lack of colored latex.
Type:— ECUADOR. Zamora-Chinchipe: Cantón Yantzaza, Parroquia las Peñas, Kinross Aurelian, Cordillera del Cóndor, Sector Frutos del Norte, cumbre de colina en la cuenca del río Machinaza, 03°46.27'S, 78°29.12'W, 1600 m, 1 November 2011, fl., C.E. Cerón, C.I. Reyes, P. Gamboa, A. Imaysela & F. Libiapoma 70424 (holotype QAP!, isotypes COL!, MA!, MICH!, QCNE!).
Monoecious shrubs or small trees 2–5 m high, ca. 5–6 cm DBH; young branches with a dense ferrugineous indumentum of stellate trichomes; bark of old branches smooth, brown-ferrugineous; latex not evident. Stipules linear, 1.5–2 mm long, with stellate trichomes, one ovoid colleter at the apex, sometimes with colleters along the margins. Petiole 1–3 cm × 1 mm, with a dense indumentum of stellate trichomes; petiolar glands 2–4, patelliform, margins usually undulate, acropetiolar, subsessile to shortly stipitate, attached to the petiole on the abaxial surface. Leaf blade narrowly ovate to lanceolate, 5–11 × 2.3–4.5 cm; adaxial surface with scattered stellate trichomes; abaxial surface with a dense indumentum of stellate trichomes; apex acute to slightly acuminate; base rounded to cordate; margin slightly dentate with numerous ovoid colleters (no longer functional) at the tip of the teeth; venation pinnate, secondary veins in 9–12 pairs, brochidodromous, raised on both surfaces, veinlets visible. Inflorescences usually terminal, sometimes axillary, nodding, 2–12 cm long, axis costate, with a dense indumentum of stellate trichomes; lower cymules bisexual, unisexual cymules with staminate flowers regularly spaced along the axis; bracts triangular, ca. 1 × 0.5 mm. Staminate flowers pedicellate, pedicel 1–6 mm long; sepals 5, ovate with acuminate apex, 3–4 × 1.5–2 mm, adaxial surface with scattered simple trichomes, abaxial surface with a dense indumentum of stellate trichomes, margin with simple trichomes; petals obovate, 3–4 × 1.8–2.2 mm, with scattered simple trichomes on both surfaces and along the margin; receptacle densely covered by simple trichomes; stamens (20)30–35(40); filaments 1–2 mm long, pilose, anthers 0.8–1 × 0.4–0.6 mm. Pistillate flowers pedicellate; pedicel 5–25 mm long; sepals 5, triangular-lanceolate, valvate, sometimes slightly imbricate at the base in young flowers, persistent, 5–8 × 3–4 mm, adaxial surface with scattered simple trichomes, abaxial surface with scattered stellate trichomes, margin pilose; petals absent; ovary densely covered with stellate-porrect trichomes; styles bifid from near the base (6 terminal tips), 1.5–2 mm long, covered with simple trichomes. Fruits subglobose, slightly trilobed, 7–10 × 6–8 mm, densely covered with stellate trichomes; columella 5–7 mm long, tip truncate, without conspicuous lobes. Seeds ovoid, smooth, shiny, dark brown or marbled, 6–7 × 4–5 mm, caruncle inconspicuous, 0.3–0.4 × 0.5–0.6 mm.
Distribution and habitat:—This species appears to be restricted to the Ecuadorian side of the sandstone plateaus of the Cordillera del Cóndor in the province of Zamora-Chinchipe (Fig. 2). It occurs in sclerophyllous shrubby vegetation in 1600–1900 m of elevation.
Common name:—Uruchmas (Shuar).
Additional specimens (paratypes) examined:— ECUADOR. Zamora Chinchipe: Cantón Yantzaza, Parroquia las Peñas, Kinross Aurelian, Fruta del Norte, Cordillera del Cóndor, sector sobre la Antena, cuchilla bajo la colina, cuenca del río Machinaza, 03°47.57'S, 78°28.56'W, 1900 m, 2 November 2011, fl., C.E. Cerón, C.I. Reyes, P. Gamboa, A. Imaysela & F. Libiapoma 70489 (MO!, QCNE!, QAP!); sector sobre el cerro Colibrí, margen derecha aguas arriba del río Machinaza, 03°45.13'S, 78°30.23'W, 1630 m, 3 November 2011, fl., C.E. Cerón, C.I. Reyes, P. Gamboa, A. Imaysela & F. Libiapoma 70663 (QAP!, QCA!); Cantón Yacuambi, Parroquia la Paz, centro Shuar Washikiat, reserva Micha Nunka, el Mirador, 03°43.59'S, 78°54.59'W, 1620 m, 2 May 2007, fr., C. Kajekai & A. Wisum 1258 (MO!, QCNE!); Cantón el Pangui, Cordillera del Cóndor, Sandstone Plateau of Contrafuerte Tres Patines, west of main Cóndor ridge, above "Jardín Botánico" of EcuaCorriente copper company, south of km 15 of Cóndor Mirador military road, 03°37.48'S, 78°26.50'W, 1685 m, 9 December 2005, fl., D. Neill & W. Quizhpe 15057 (MICH!, MO!, QCNE!).
Discussion:— Croton condorensis shows no clear affinity to any of the Croton sections established by van Ee et al. (2011), although the species shares several characters with members of sect. Cyclostigma Grisebach (1859: 42), as suggested by the sectional identification key of van Ee et al. (2011), namely: habit (shrub to small tree), stellate indumentum, presence of petiolar glands, leaf blade without marginal glands, bisexual cymules on the lower section of the inflorescence, and numerous stamens. Conversely, latex is abundant and usually showy (yellow, organge or reddish) in members of sect. Cyclostigma (Riina et al. 2009), but it is not evident in Croton condorensis. The narrow shape of the leaves of C. condorensis is also unusual in species of sect. Cyclostigma. Pistillate flowers are scarce, or frequently absent, in the examined specimens of Croton condorensis, whereas in sect. Cyclostigma they are usually much more numerous per inflorescence. The surface of the seeds in sect. Cyclostigma is usually rugose, or with some kind of ornamentation. In contrast, the seeds of Croton condorensis have a smooth, shiny and marbled surface. In addition, none of the Ecuadorian species of sect. Cyclostigma grow on the type of high elevation sclerophyllous vegetation where C. condorensis occurs. These observations, along with the morphological differences listed above, suggest that the new species could be an isolated lineage within Croton. However, the indication of sect. Cyclostigma as the most likely section to which C. condorensis belongs, as suggested by the sectional key (van Ee et al. 2011), cannot be ruled out until additional specimens as well as sequence data from this species become available for additional morphological and phylogenetic analyses.
description: Published as part of Riina, Ricarda, Vigo, Marco A. & Cerón, Carlos E., 2014, Croton condorensis: an enigmatic new species of Euphorbiaceae from southern Ecuador, pp. 154-158 in Phytotaxa 164 (2) on page 155, DOI: 10.11646/phytotaxa.164.2.10, http://zenodo.org/record/5132696