Anthurium mucuri E.G.Gonç. & L.F.A. de Paula, 2016

Gonçalves, Eduardo G. & De Paula, Luiza F. A., 2016, A new species of Anthurium (Araceae) from Minas Gerais State, Southeastern Brazil, Phytotaxa 247 (4), pp. 281-286 : 281-284

Anthurium mucuri E.G.Gonç. & L.F.A. de Paula , sp. nov.

Ad sectione Urospadix Schott pertinens. Internodia brevibus, 2–4 cm diam.; cataphyla lanceolata, 3–6 cm longa, 1–1.3 cm lata, in fibras soluta; petiolus 3–4 cm longus, 0.4–0.5 cm diam., U-formatus, adaxiale applanatus, marginibus acutis; lamina coriacea, lanceolata vel elliptica , 12–32 cm longa, 5–7 cm lata; nervis primariis lateralibus pluribus, arcuatis; pedunculus 22–30 cm longus, 0.3–0.4 cm diam.; spatha coriacea, ex rosea viridis , ovata vel lanceolata, 5–8 cm longa, 1.5–2.3 cm lata; spadix castaneus vel purpurascens, 7–9 cm longus, 0.7–0.8 cm ad basim diam., sursum attenuatus .

Type:— BRAZIL: Minas Gerais: Teófilo Otoni, Afloramento rochoso, lado esquerdo da MG 418, cerca de 30 km norte de Teófilo Otoni, 17 o 51’22’’S, 41 o 15’39’’W, 560 m, 16 April 2011, de Paula, L. F. A. & Augsten, M.D. F. 242 (holotype: BHCB!) ( Figs. 1 and 2 ).

Acaulescent, rosulate herb. Stem erect, internodes short, 2–4 cm diam.; roots greyish white to greenish, forming a thick mass around the stem; cataphylls triangle-shaped, 3–6 cm long, 1–1.3 cm wide, persisting as a mass of coarse fibers. Leaves: erect to slightly spreading; petioles 3–4 cm long, 0.4–0.5 cm diam., U-shaped, flattened with raised acute margins adaxially, rounded abaxially, fresh material medium matte green; geniculum visibly thicker than the petiole, clear matte green, 0.5–0.8 cm long; sheath 0.8–1 cm long; blades lanceolate to elliptic, shortly apiculate at apex, obtuse to rounded at base, 12–32 × 5–7 cm, broadest at middle or slightly below; the margins very weakly undulate and conspicuously revolute in dry material; upper surface matte, medium green, lower surface matte, paler; both surfaces drying pale brown, a little paler abaxially; midrib slightly prominent above, round below, adaxially with abundant white speckles; venation poorly visible on both sides in both living and dried leaves, lateral veins numerous, primary veins almost impossible to separate from the interprimary veins, departing midrib at 25–35 o angle, arcuate, slightly prominent on upper surface, raised below; tertiary veins prominulous in both surfaces in dried leaves, reticulate veins almost invisible; collective vein 3–8 mm from leaf margin. Inflorescences: usually erect or slightly spreading, longer than the leaves; peduncle 22–30 cm long, 0.3–0.4 cm diam., 7–9 times longer than the petioles; spathe erect to patent at anthesis, coriaceous, ovate to lanceolate, semi-matte medium green and tinged with red outside, concolorous but often glaucous inside, usually tinged in red close to margins or toward the apex, densely white speckled in both surfaces in fresh material, 5–8 × 1.5–2.3 cm, broadest slightly above the base, sometimes almost at middle, inserted at 45 o angle on the peduncle, cuspidate at apex, cuneate to obtuse at base, spathe margins meeting acutely; spadix brown to purplish, stipitate for 2–3 mm, tapered, 7–9 cm long, 0.7–8 cm diam at base, 3–4 mm diam. at apex, broadest near base; flowers rhomboidal, 3–3.5 × 3–4 mm; 4–6 flowers visible in principal spiral, 7–8 flowers visible in alternate spiral; tepals matte; lateral tepals 1 mm wide, inner margins straight, the outer margins 2-sided; pistils not emergent; stigma rounded; stamens not covering the stigma; filaments not exerted; anthers 0.5–0.6 × 0.4–0.5 mm, thecae ovoid, 0.5 × 0.2–0.3 mm. Infructescence with spathe persistent, erect or spreading for most time, pendant only when berries are almost ripe; spadix up to 9.5 cm long, up to 1.3 cm diam.; berries green, greyish at apex, pale green at base, broadly obovate, 5–6 mm long, 4–6 mm diam.; mesocarp fleshy, with numerous raphid cells, seed 1–2 per bery, cream when fresh, a little darker when exposed to air, obovate, 2–3 mm long, 1–2 mm diam.

Etymology: —The epithet mucuri commemorates the region known in Brazil as “Mucuri Valley Mesoregion ”, a group of counties with similar culture and geographic features around the drainage system of the Mucuri River.

Distribution and habitat: —Saxicolous in vegetation patches, bounded by bare rock, in fully exposed places in the sun. It is only known from inselbergs in the Northeastern Brazilian state of Minas Gerais, nearby the city of Teófilo Otoni. It occurs in middle elevated uplands, around 600 m above the sea level.

The species is commonly found in vegetation patches with the predominance of monocotyledonous mats and succulent species. These mats are usually formed by members of Bromeliaceae (e. g. Alcantarea spp. , Encholirum spp., Pitcairnia spp. ), Cyperaceae (e. g. Trilepis lhotzkiana Nees (1834: 267)) and Velloziaceae (e. g. Barbacenia spp. , Vellozia spp. ), some of the species are known as desiccation-tolerant plants ( Porembski 2007, Porembski & Barthlott 2000). Succulent species are represented by Cactaceae (e. g. Coleocephalocereus spp. , Pilosocereus spp. ), Orchidaceae (e. g. Cyrtopodium spp. , Pseudolaelia spp. ) and also Araceae (e. g. Philodendron edmundoi Barroso (1957: 90)) .

Additional species examined:— BRAZIL. Minas Gerais: Teófilo Otoni, Afloramento rochoso, lado esquerdo da MG 418 , cerca de 30 km norte de Teófilo Otoni, 17 o 51’22’’S, 41 o 15’39’’W, 560 m, 8 January 2011, de Paula, L. F. A. et al. 136 ( BHCB!) ; Same Locality , 16 April 2011, de Paula, L. F. A. & Augsten, M.D. F. 242 ( BHCB!) .

Morphological comments: — Anthurium mucuri can be recognized by the erect leaves with nerves hardly detectable in living plants, usually with revolute margins. The peduncles are almost invariably longer than leaves and the greenish and relatively broad spathes are one of the most remarkable aspect. It seems to be closely related to A. viridispathum , also described from Brazilian inselbergs much closer to the Atlantic shore ( Gonçalves 2005). From this species it differs for overall smaller dimensions and for the proportionally narrower spathe, rarely less than 6 times longer than broad (up to 2.4 times longer than broad in A. viridispathum ). Moreover the spathes are also glaucous in the inner surface in A. mucuri , specially during anthesis, whereas spathes are matte green in A. viridispathum . Poorly developed (or young) specimens can have broader spathes, but they are usually more tinged in red than A. viridispathum , which is essentially green.Another difference is that the fruiting spadix is held erect in A. mucuri during most fruiting stage, whereas it becomes soon pendant in A. viridispathum .

Anthurium mucuri is tentatively placed in the section Urospadix Engler (1878) subsection Obscureviridia Engler (1898) , mainly because of the thick blades with veins poorly prominent in fresh material. However, infrageneric taxonomy of Anthurium , especially at the subsectional level, seems to be strongly artificial based on the preliminary phylogenetic analysis ( Carlsen & Croat 2013).

Preliminary conservation status: —The species is known from a few inselbergs in the northeastern part of Minas Gerais state, Brazil. According to the IUCN (2001) guide- lines, the species should be evaluated as Data Deficient. It is necessary to highlight that inselberg biodiversity is under serious threats ( Meirelles et al. 1999, Burke 2003). Besides the removal of the buffer lowland vegetation in the surrounding areas of inselbergs, which facilitates biological invasion (Porembski 2000; de Paula et al. 2015), these rock outcrops are also experiencing a set of threats including quarrying, mining and unsustainable extraction of attractive species of the flora ( Martinelli 2007). This scenario is even more worrying given the high beta-diversity, i. e. the high species turnover between neighbouring inselbergs, and also the high endemism rate in the above mentioned region ( Porembski et al. 1998, Porembski 2007). Furthermore, the number of recently described new species that have been found in inselbergs in Northeastern Minas Gerais is outstanding, including Axonopus graniticola Viana (2013: 9) ( Poaceae ) and Bradea borrerioides Oliveira & Sobrado (2016: 84) ( Rubiaceae ). Thereby, the vegetation associated with these rock outcrops can be considered a conservation priority in the vegetation mosaic of the Atlantic Forest ( Leão et al. 2014).

Figures

FIGURE 1. Anthurium mucuri E.G.Gonç. & L.F.A. de Paula. A. Habit. B. Inflorescence. C. Flower, longitudinal section. D. Tepal, side view. E. stamen, still within the tepal. F. flower, upper view. G. Petiole, cross section. H. Midrib, cross section.All from the holotype (de Paula, L.F.A. & Augsten, M.D.F. 242) by E.G.Gonçalves.

FIGURE 2. Anthurium mucuri E.G.Gonç. & L.F.A. de Paula.A. Flowering specimen growing with Velloziaceae.B. Inflorescence in early female phase. C. Inflorescence in female phase, visited by fruit-flies in cultivation. D. Stem of a cultivated specimen, showing erect stem with shredded cataphylls. E. Unripe fruiting spadix developed in cultivation. Photo A-B by L.F.A. de Paula (from de Paula, L.F.A. et al. 136), photo C-E by E. Gonçalves (from de Paula, L.F.A. & Augsten, M.D.F. 242).