Manihot takape De Egea & Pena-Chocarro, 2018

Elsam, Juana De Egea, Pena-Chocarro, Maria del Carmen, Mereles, Fatima & Cespedes, Gloria, 2018, Manihot takape sp. nov. (Euphorbiaceae), a new tuberous subshrub from the Paraguayan Chaco, PhytoKeys 103, pp. 1-12 : 2-6

Manihot takape De Egea & Pena-Chocarro sp. nov. Figs 1 , 2 and 3

Type.

PARAGUAY. Boquerón: Neuland, Parque Valle Natural , 22°34'21"S; 60°05'31"W, 19 Feb 2018, fr., J. De Egea, F. Mereles & S. Fernández 1793 (holotype: FCQ; isotypes: BM, CTES, G) .

Diagnosis.

Subshrubs 0.5-0.8(-1) m tall, all parts glabrous; stems branched from base, suberect to decumbent; petiole attachment basal to occasionally narrowly peltate (less than 0.2 cm from lamina base), lamina unlobed or shallowly to deeply 3(-5)-lobed, several intermediate states found in the same plant; inflorescence a cluster of 2-6 subspicate racemes 14-33 cm long; flowers creamy-white, occasionally reddish, glabrous; pistillate flowers geminate, long pedicellate, sepals distinct, disc plicate; staminate flowers numerous, subsessile, sepals connate 1/4 their length, disc lobulate; capsules light green, unwinged, smooth when fresh, rough when dried.

Description.

Subshrubs 0.5-0.8(-1) m tall. Roots slender with scattered subglobose to slightly elongated tubers, 5-10 cm diameter, ligneous outside, starchy, fibrous and creamy-white inside. Latex white. Stems branched from base, suberect to decumbent, leaning on adjacent vegetation, hollow, glabrous, green, occasionally reddish. Leaves alternate, widely spaced on stem, light green; stipules 0.2-0.3 cm long, narrowly lanceolate to filiform, margins entire, glabrous, caducous; petioles 1.5-8(-10) cm long, terete, glabrous, petiole attachment basal to occasionally narrowly peltate (less than 0.2 cm from lamina base); lamina membranaceous, smooth and glabrous on both sides, with a tuft of hairs on the adaxial side at the point of attachment of petiole, venation camptodromous; lamina unlobed to shallowly or deeply 3-lobed, sometimes with 2 additional smaller basal lobes, several intermediate states found in the same plant; sinus never reaching the lamina base, width of lamina between lamina base and sinus> 0.5 cm. Unlobed laminas 3-9(-11) × 2.5-7(-10) cm, ovate to suborbicular, base obtuse, truncate or subcordate, rarely acute, margins entire or slightly sinuate, apex acuminate; leaves mostly unlobed, especially those near the inflorescence. Lobed leaves: medial lobes 4-7 × 3-6 cm, elliptic, ovate or obovate, sometimes pandurate, apex acuminate, rarely obtuse. Inflorescence bisexual, terminal; a cluster of 2-6 racemes arising from a common base, all parts glabrous; racemes subspicate, 14-33 cm long; bracteoles and bractlets 2-3 mm long, 1 mm wide, setaceous, narrowly lanceolate, margins entire. Pistillate flowers 2, restricted to the base of the inflorescence, geminate, all parts glabrous; pedicels ca. 1-2 cm long; sepals 5, distinct, 1 cm long, creamy-white, occasionally with reddish pigmentation; disc lobed, 1 mm thick, creamy-white; ovary 3-carpellate, subglobose, styles very shortly connate, stigmas 3, profusely lobulate. Staminate flowers numerous, aggregated toward the apex of the inflorescence; pedicels 0.5 mm; buds ovoid-ellipsoid; sepals 5, connate 1/4 length, 1 cm long, creamy-white, occasionally with reddish pigmentation; disc lobed, 1 mm thick, creamy-white; stamens 8-10, filaments 3.5-5 mm long, subequal, anthers 4 mm long, oblong. Capsules 7.5-15 mm diameter, surface rough in dried specimens, to 20-23 mm diameter and smooth in fresh specimens, subglobose to slightly elongated, unwinged, apex rounded to depressed, dehiscence septicidal and loculicidal. Seeds 9-11 × 7-8 mm, 4-5 mm depth, oblong-elliptic, light glaucous greenish-grey, smooth and slightly lustrous, with few 1-2 mm dark spots towards the sides; caruncle usually prominent, light brownish-grey, opaque, extending obliquely from apex to 4 mm on the ventral side.

Distribution and ecology.

This species has been collected in dry areas of the Paraguayan Chaco, more specifically within the Departments of Boquerón and Presidente Hayes (Fig. 4 ). These areas are characterised by sandy and loose soils (regosols) resulting from silted palaeo-riverbeds of the Pilcomayo river delta. The species is frequent in open wooded savannahs, locally called espartillares, dominated by the grass Elionurus muticus (Spreng.) Kuntze (espartillo) and scattered with tree species such as Schinopsis cornuta Loes. ( Anacardiaceae ), Astronium fraxinifolium Schott ( Anacardiaceae ), Jacaranda mimosifolia D.Don ( Bignoniaceae ) and Tabebuia aurea Benth. & Hook.f. ex S.Moore ( Bignoniaceae ). Based on the data available so far, the restricted distribution of Manihot takape could represent an endemism of the dry Chaco. However, more surveys and collections will be needed to confirm the extension of the species distribution range.

Phenology.

The species has been collected with flowers and fruits from November to February and with fruits only from January to February.

Etymology.

The specific epithet stems from the vernacular name takape (Guarani language). This word is used for a particular habitat characterised by a wooded savannah or open woodland ( Bertoni 1940). The word is also applied to small woody plants (i.e. subshrubs). This is based on the word takã (twig or branch) and the suffix ‘pe’ (short or dwarf). Both meanings fit the newly described species of Manihot .

Conservation status.

A preliminary conservation assessment with the GeoCat Tool indicates that M. takape can be initially considered as Endangered, with an extent of occurrence of 1,887 km2 and an area of occupancy of 28 km2 (based on an UICN default cell width of 2 km). Furthermore, with only 5 locations known to this date and considering the high deforestation and land use changes in the Paraguayan Chaco ( Arévalos et al. 2018, Cardozo et al. 2013, Huang et al. 2009, Mereles and Rodas 2014, Yanosky 2013), the preliminary UICN category proposed for this species is Endangered B1ab(iii)+2ab(iii). It is worth mentioning that the type locality, known as Parque Valle Natural in Neuland, Boquerón, is a private reserve of approximately 0.5 km2 that harbours a small population of the new species. The current conservation status of the remaining four locations is unknown. Further field observations and collections are strongly recommended to achieve a more conclusive conservation assessment.

Additional specimens examined.

PARAGUAY. Boquerón: Colonia Fernheim, Colonia 22 (Neuwiese), 22°21'S, 60°01'W, 9 Nov 1987, P. Arenas 3313 (FCQ); Neuland, Parque Valle Natural, 22°34'S; 60°06'W, 18 Jan 1993, L. Pérez, S. Bertoni, M. Quintana, B. Benítez, G. Marín & G. Rubira 2736 (CTES); Parque Valle Natural, 25 km S de Filadelfia, 22°34'S; 60°05'W, 7 Dec 1992, A. Krapovickas & C.L. Cristóbal 44223 (CTES); Parque Valle Natural, 25 km S de Filadelfia, 22°34'S; 60°05'W, 7 Dec 1992, A. Krapovickas & C.L. Cristóbal 44224 (CTES, F), Parque Valle Natural, 12 km S de Filadelfia 22°34'S; 60°05'W, 28 Feb 1991, R. Vanni, A. Radovancich & A. Schinini 2455 (CTES) . Presidente Hayes: Colonia Menno, Paz del Chaco , 23°25'S; 58°54'W, 15 Nov 1987, P. Arenas 3336 (FCQ); Estancia Yrendá, 22°48'S; 59°33'W, 15 Feb 1993, L. Pérez, S. Bertoni, T. Florentín & A. Bogado 3042 (CTES); Estancia Yrendá, 22°48'S; 59°33'W, 15 Feb 1993, L. Pérez, S. Bertoni, T. Florentín & A. Bogado 3043 (CTES); Tte. 1°Irala Fernández, próximo al centro urbano, 22°48'01"S; 59°37'05"W, 19 Feb 2012, O. Aquino & A. Quarti 470 (FCQ) .

Figures

Figure 1. Manihot takape. A Habit (Krapovickas & Cristobal 44224) B Pistillate flower with calyx open (Krapovickas & Cristobal 44224) C Staminate flower (Aquino & Quarti 470) D Staminate flower with calyx split and open (Aquino & Quarti 470) E Dried capsule (J. De Egea et al. 1793) F Seed, ventral side (J. De Egea et al. 1793). Drawn by Laura Simon.

Figure 2. Manihot takape. Herbarium specimen showing different leaf forms and a particularly long inflorescence (Krapovickas & Cristobal 44223). Image used with permission and provided by the Instituto de Botanica del Nordeste (CTES).

Figure 3. Manihot takape (J. De Egea et al. 1793). A Habit B Uprooted plant C Roots in cross-section D-E Leaves - note the variability in leaf forms F Immature fruit.

Figure 4. Map of Paraguay showing the known records of Manihot takape.