Lessingianthus concepcionis M.B. Angulo & Dematteis, 2016

Angulo, Maria Betiana & Dematteis, Massimiliano, 2016, Lessingianthus concepcionis (Asteraceae, Vernonieae), a new octoploid species endemic to northern Paraguay, Phytotaxa 265 (3), pp. 267-272 : 268-271

Lessingianthus concepcionis M.B. Angulo & Dematteis , sp. nov. ( Fig. 1 )

Type:─ PARAGUAY. Concepción: 1 km E de Huguá Poí [S 23º12ʹ38ʺ, W 57º14ʹ25ʺ], 4 March 2009, M. Dematteis, M. Franco & H. A. Keller 3230 (holotype CTES!, isotype FCQ!, SI!).

Diagnosis:―Differs from L. niederleinii ( Hieronymus 1897: 681) Robinson (1988: 946) by its leaves with denticulate and revolute margins, tomentose beneath, and glandular trichomes on corolla lobes (versus leaves with entire or briefly serrate, never revolute margins, and glandular and non-glandular trichomes on corolla lobes).

Erect shurb, 2.5 m tall. Stems single, lanate, densely leafy to the inflorescence. Leaves coriaceus, sessile, 7–8 × 4.5–5 cm. Leaf blades lanceolate, acute at apex, base attenuate, scabrous above, tomentose beneath, pinnatinervate, secondary veins prominent above, margins denticulate, revolute. Capitula numerous, sessile grouped on seriate-cymose branches. Bracts of the synflorescence leafy, lanceolate, 11–14 mm long. Involucre campanulate, 11–12 × 9–10 mm; phyllaries in 6–7 series, slightly imbricate, coriaceous, ciliate at margin, outer phyllaries linear, 3–4× 1.3–1.6 mm, subulate and recurved at the apex, middle phyllaries linear to oblong-linear, 5–6.5 × 1.8–1.9 mm, subulate and slightly recurved at the apex, inner phyllaries oblong-lanceolate, 8.5–9 × 1.6–1.9 mm, acute, papillose. Florets 20–30; corolla violet, 10–12 mm long, corolla lobes with glandular trichomes. Anthers sagittate, techae 3–3.5 long, apical appendage ovate-lanceolate, 0.6 mm long. Styles 12.5 mm long, without basal stylar node. Cypselas turbinate, ribbed, laxly sericeous-pubescent, 4–4.5 mm long, fruit wall with cubic and prismatic crystals. Pappus biseriate, white, outer series scales lanceolate, fimbriate, 0.8–1.2 mm long, inner series bristles 6–7 mm long. 2n=128.

Distribution and habitat: —This taxon grows in Paraguay, only known from Concepción Department. It grows in areas with calcareous soils in cerrado habitats.

Conservation status:— Lessingianthus concepcionis has a limited area of occupancy estimated to be less than 500 km 2 in a severely fragmented area and is currently only known from three localities. In additon, the continuing decline of its habitat due to the use as farm land which is from time to time subject to grazing and trampling by livestock could rapidly change the threat status. Therefore, the new species is considered Endangered: EN B 1ab(iii), according to the IUCN red list criteria ( IUCN 2015).

Etymology:—The specific epithet refers to the region where the species occur.

Additional specimens examined (paratypes): ─ PARAGUAY. Concepción: Aldea Pa’i Tavytera “ Boquerón ”, S 22º 52ʹ 50,2ʺ, W 56º 51ʹ 18,7ʺ, 147 m, 5 March 2009, H. A. Keller, M. Dematteis & M. Franco 6653 ( CTES) ; 25 km N de Aldea Aborigen Boquerón, camino a Puentesiño , S 22º35ʹ33ʺ, W 56º49ʹ50ʺ, 5 March 2009, M. Dematteis, M. Franco & H. A. Keller 3300 ( CTES, FCQ) .

Discussion: ─The new species seems to be closely related to L. niederleinii but it differs in the margin and indumentum of leaves, number of phyllary series, trichome type of corollas and chromosome number. The most important differences between these species are summarized in Table 1.

Lessingianthus concepcionis has glandular trichomes on corolla lobes ( Fig. 2A ), which were designated as “ Type III” by Angulo & Dematteis (2014a). These glandular trichomes occur on the dorsal side of corolla lobes and they have a uniseriate stalk and a unicellular head ( Fig. 2B ). Lessingianthus niederleinii has also glandular trichomes “ Type III” but it has non-glandular Types I (unicellular, short) and II (multicellular, long, with a terminal cell longer than the other cells) ( Angulo & Dematteis 2014a).

The new taxon is an octoploid entity with 2n=8x=128 ( Fig. 2C ), which constitutes the first chromosome count for the species and the third report of the octoploid ploidy level in the genus. On the other hand, L. niederleinii is hexaploid with 2n=6x=96, as it has been supported by numerous chromosome counts in several populations from Paraguay and Argentina ( Angulo & Dematteis 2012a). Other octoploid taxa in Lessingianthus are L. scabrifoliatus ( Hieronymus 1897: 677) Robinson (1994: 29) and L. hystricosus ( Cabrera & Dematteis 1999: 103) Dematteis (2010: 238) . All counts carried out in several populations from Bolivia ( L. scabrifoliatus ) and Paraguay ( L. hystricosus ) showed 2n=128 (Dematteis 2002, Angulo & Dematteis 2012a). However, the new species differs from L. scabrifoliatus in urceolate-campanulate involucre, 50–60 florets per head, mucronate apex of leaves, outer phyllaries with mucronate apex, glandular and non-glandular trichomes on corolla and cypsela. Regarding L. hystricosus , this taxon is only known to the central and eastern Paraguay and is distinguished from L. concepcioni s by leaves with denticulate and undulate margins, 4–5 phyllary series, outer phyllaries linear and mucronate at apex, glandular and non-glandular trichomes on cypselas.

Lessingianthus concepcionis is locally used for the treatment of parasitic diseases based on the information obtained from interviews to several members of Aldea Pa’i Tavytera “ Boquerón ” (Concepción, Paraguay) carried out by collectors. This new taxon is locally known as “jagua pety” and their roots in decoction are used as an antiparasitic. Vernonanthura tweedieana ( Baker 1873: 99) Robinson (1992: 74) is also known under the same common name as suggested by Portillo et al. (2005). These authors studied chemical constituents of roots in specimens of Paraguarí ( Paraguay) and they identified a sesquiterpene as the antifungal agent. This chemical compound characterizes the Vernonieae tribe (Kelley & Robinson 2009) and perhaps it would also be responsible for the antifungal activity in L. concepcionis .

Figures

FIGURE 1. Lessingianthus concepcionis. A: Plant. B–C: Detail of leaf margin. B: adaxial surface. C: abaxial surface. D: Capitulum. E–G: Outer phyllaries. H–I: Middle phyllaries. J–K: Inner phyllaries. L: Cypsela with pappus. (A–L: from Dematteis et al. 3230, CTES; illustrated by Mirtha L. Gómez).

FIGURE 2. Somatic chromosomes and floral microcharacters of Lessingianthus concepcionis. A: Metaphase plate, 2n=128. B: Corolla lobe tip with glandular trichomes (arrow). C: Detail of glandular trichome Type III. Scale bars= A–B: 10 μm, C: 50 μm.