Syngonanthus vittatus M.T.C.Watan. & Echternacht, 2015

Syngonanthus vittatus M.T.C.Watan. & Echternacht View in CoL , sp. nov.

Type:— BRAZIL. Goiás: Alto Paraíso de Goiás, Chapada dos Veadeiros, estrada Alto Paraíso de Goiás - Teresina de Goiás, Fazenda Água Fria , em campo limpo após a piscina, próximo a vereda e mata de galeria, 14 º 06’21.7’’S, 47 º 30’33.6’’W. 19 July 2012 (fl), M. Watanabe & W. Watanabe 377 (holotype SPF! GoogleMaps , isotype F! GoogleMaps ). Figures 2H–N View FIGURE 2 & 4 View FIGURE 4 .

The new species is similar to Syngonanthus arenarius var. heterophyllus but differs by involucral bracts narrowly lanceolate with apex markedly acute and petals glabrous in pistillate flowers. Syngonanthus vittatus is also similar to Syngonanthus densifolius var. majus differing by all characteristics mentioned above as well the rosette leaves recurved.

Perennial herbs, 20–40 cm tall. Roots 0.2–1.5 mm in diameter, white to cream-colored, spongy. Rhizome 0.7–3.3 cm × 2.5–3.5 mm, horizontal to oblique, often branched, tomentose to villous, with white, dense and woolly curled trichomes; each branch giving rise to a rosette of leaves, each rosette bearing 1–3 synflorescences. Rosettes 19–41 mm in diameter. Leaves 9.0–22.5 × 0.3–1.0 mm, linear to narrowly lanceolate, flat to semi-terete, apex acute, base truncate, recurved, coriaceous, striate abaxially with 3–5 conspicuous veins, only the midvein visible on upper surface in young leaves; pilose on both surfaces, with arachnoid trichomes and adpressed trichomes adaxially, filamentous hairs and adpressed trichomes abaxially, mainly concentrated on midvein, ca. 0.3 mm long; basal sheath slightly enlarged, 0.5–1.0 mm wide, pale and achlorophyllous at base. Synflorescences with a primary axis bearing a lax umbel of 1–5 inflorescences at the apex. Synflorescence axis 5.0– 8.5 cm long, emerging from the center of the rosette, erect to flexuous, yellow-reddish when young, dark reddish brown in maturity, pilose at base with filamentous trichomes, glabrescent, becoming tomentose near the apex with simple filamentous and capitate trichomes. Bracts of synflorescence axis usually restricted to the apex, rarely a few tiny scattered bracts along the axis ca. 3 mm long; apical bracts 1–30 × 0.3–1.0 mm, whorled, patent, the external series lanceolate, progressively elongating from the outer toward the inner series, the internal series linear, apex acute to rounded, erect, pubescent on both surfaces with capitate filamentous trichomes. Inflorescences composed of a closed spathe subtending a scape with a capitulum at the apex. Spathes 3.5–5.5 cm long, chartaceous, cylindrical, obliquely opened, apex acute, erect, recurved or rarely involute, tip erect to uncinate, margin minutely involute, ciliate, adaxial surface glabrous to glabrescent, abaxial surface pubescent with capitate trichomes. Scapes erect, 9–30 cm long, greenish to straw-colored with age, 4(–5)-costate, sparsely hairy to densely pilose with erect to patent glandular hairs and appressed, and simple trichomes, pubescent near the apex with a collar of patent, simple filamentous and capitate [gland-tipped] trichomes. Capitula 5–12 mm in diameter, obconic, later becoming depressed-hemispherical. Involucral bracts in 4–6 series, all similar in color, light to dark brown, often with a reddish tinge, with a lighter longitudinal band in center and a darker pigmentation on the margins, adaxial surface glabrous, abaxial surface strigose, ciliate, with patent, simple trichomes, rarely also capitate trichomes ca. 0.5 mm long; external series 1.5–2.0 × 0.5–0.8 mm, triangular to ovate, apex acute, bracts progressively elongating toward the internal series, middle series 4–5 × 1 mm, narrow elliptic, apex acute, internal series 3.0–5.5 × 0.7–1.0 mm, inner series surpassing the flowers by 0.1–0.3 mm, narrow-lanceolate, elliptic, rarely narrow-oblanceolate, apex acute; receptacle hemispheric, pilose. Floral bracts absent. Flowers 3-merous, 60–110 per capitulum, staminate and pistillate generally equal in number, with contrasting colors, staminate flowers darker and concentrated at the border of the capitulum. Staminate flowers 2.5–3.5 mm long, including pedicels; pedicels 0.5–1.0 mm long; sepals 2.0– 2.5 mm long, coppery brown, shortly fused at base, concave, membranous, usually two sepals similar in form, elliptic to lanceolate (-oblanceolate) with acute apex, slightly curved, asymmetrical, and the third different, slightly irregular-subspathulate with round to truncate apex, but occasionally occurs a reversal of forms, or occasionally the three sepals slightly different, margins ciliate, adaxially glabrous, abaxially setose with simple filamentous trichomes ca. 0.5 mm long; petals ca. 2 mm long, hyaline, membranous, fused, tubulose, lobes triangular, obtuse, involute after anthesis, glabrous; filaments free, anthers ca. 0.6 mm long, white; anthophore ca. 0.3 mm long; pistillodes 3, ca. 0.2 mm long, clavate, papillose at apex. Pistillate flowers 2.4–3.5 mm long, including pedicels of 0.4–1.5 mm long; sepals ca. 2 mm long, elliptic, concave, apex acute to obtuse, base thickened, free, cream to light castaneous, hyaline and membranous toward the apex, dark reddish brown-colored at apex, ciliate, hairy on the inside, with simple filamentous trichomes up to 1 mm long, glabrous outside; petals about equaling the sepals, 1.8–2.7 mm long, oblanceolate, fused at the distal third, membranous, white to hyaline, glabrous, the lobes triangular-rounded to obtuse, involute after anthesis; ovary ca. 0.6 mm long; style column 0.2–0.4 mm long, cream-colored; appendages ca. 0.5 mm long, the glandular apex capitatecurved; stigmatic branches simple, ca. 1.5 mm long. Seed ca. 0.40 × 0.25 mm, ellipsoid, reddish-brown colored.

Etymology:— The specific epithet refers to the well-marked longitudinal stripe evident in the center of the involucral bracts.

Notes and taxonomic affinities:— In the field, the species looks superficially similar to Paepalanthus ( FIG. 4A View FIGURE 4 ), because of its pilose capitula and dark involucral bracts. However, a closer examination reveals the compound inflorescences (synflorescences), with a differentiated, usually leafless primary axis, a feature that does not occur in Paepalanthus . In addition, the species has petals of pistillate flowers fused in the distal part and free at the base, and staminate flowers isomerous an exclusive set of characters of Syngonanthus ( Giulietti et al. 2012) .

Syngonanthus vittatus belongs to the same morphological group as S. incurvifolius , which also includes Syngonanthus arenarius , S. densifolius var. brachyphyllus and S. densifolius var. majus . All these species share a similar architecture and dark and pilose involucral bracts with a contrasting pale longitudinal band. Syngonanthus vittatus differs from all of them by the involucral bracts narrowly lanceolate to linear, with a narrower and more conspicuous pale stripe, composing a laxer involucre ( FIG. 4G View FIGURE 4 ); the other species have large elliptical to obovate bracts, forming a denser involucre ( Fig. 4F, 4H–I View FIGURE 4 ).

The flowers of Syngonanthus vittatus are very similar to those of S. arenarius var. heterophyllus (1903:260), except that the former has petals of pistillate flowers glabrous ( FIG. 4J–K View FIGURE 4 ; vs. petals pilose, FIG. 4L View FIGURE 4 ) and smaller flowers (up to 3.5 vs. 4.5 mm). In addition, S. vittatus has pistillate and staminate flowers strongly contrasting in colour, the staminate with brown sepals and the pistillate with cream sepals ( FIG. 4M–N and 4K–J View FIGURE 4 , respectively), whereas both types of flowers in S. arenarius var. heterophyllus have a similar pigmentation ( FIG. 4L; 4O View FIGURE 4 ), cream at base and reddish-brown at apex.

Other features differentiating Syngonanthus vittatus from S. incurvifolius and S. densifolius var. majus are the rosette leaves recurved ( FIG. 4B View FIGURE 4 ) (vs. incurved in the distal half or flexuous, respectively, FIG 3A–B View FIGURE 3 ), the synflorescence axis often bearing tiny scattered bracts along its length (vs. bracts restricted to the apex), and the petals of pistillate flowers glabrous (vs. pilose). Syngonanthus vittatus also differs from Syngonanthus densifolius var. brachyphyllus by the narrower leaves (0.3–1.0 mm vs. 2.0–5.0 mm), with simple and adpressed trichomes (vs. only simple) and striate adaxial surface (vs. reticulate).

Additionally, the evident asymmetrical sepals of staminate flowers are an important characteristic shared with S. incurvifolius and the other species previously cited ( FIG. 4C–E View FIGURE 4 ).

Phenology:— Flowering of Syngonanthus vittatus occurs during the dry season (winter), from July to September. This period coincides with all collections reported for this species. Most Syngonanthus from Chapada dos Veadeiros bloom at the same time, for example, S. decorus Moldenke (1976:485) and S. densifolius var. majus . Seeds mature at the end of the dry season, implying a dispersal period concomitant with the rains and possible hydrochory.

Habitat and distribution:— All collections are known from the same population as the type, at the farm called “Água Fria”, except by a single record from waterfall “São Bento”. These localities are about 10 km apart and close to recreational and agricultural areas. The expansion and intensification of human activities in the area threatens the natural surroundings. The limited distribution of the known populations contrasts with a local abundance of individuals, and further fieldwork may reveal other populations. Syngonanthus vittatus occurs outside conservation units, although very close to the boundaries of the PNCV. The species occurs over hydromorphic soils, in moist grasslands or wet campo, a common physiognomy on floodplains between Cerrado sensu stricto and gallery forest ( Ratter et al. 1997). These wet campos occur on well-drained sandy soils, which become waterlogged during summer and quite dry in winter, a variation that constrains tree growth and prevents forest formations ( Ratter et al. 1997), favoring the occurrence of herbs such as S. vittatus .

Conservation status:— This species is classified as critically endangered, according to criteria B1ab and B2ab of IUCN (2001, 2015). The taxon is known only from two populations, both on privately owned land hosting human activities that may threaten the species with extinction. Syngonanthus vittatus has an area of occupancy of 12 km 2. Conservation status is endangered, as evaluated by CNCFlora according to the IUCN (2001, 2015), matching criteria B2ab(i,ii,iii) (Negrão 2014b).

Additional specimens examined:— BRAZIL. Goiás: Alto Paraíso de Goiás. Est. 11-Chapada dos Veadeiros , mata, 06 August 1972, Rizzo 8236 ( SPF) ; 9 km de Alto Paraíso / São Jorge, cachoeira São Bento , campo úmido próximo a floresta de galeria, 09 September 1994, Silva et al. 2315 ( IBGE, SPF) ; Fazenda Água Fria , próximo a sede da fazenda, borda de mata de galeria, 14º09’07’’ S, 47º37’08’’W, 06 June 1997, Munhoz et al. 462 ( UB) GoogleMaps ; Fazenda Água Fria, cerca de 10 km em direção a Teresina de Goiás , campo limpo úmido, borda de cerrado rupestre e mata de galeria, 14°04’21.7’’S, 47°30’33.6’’W, altitude 1488 m, 17 June 2000, Munhoz et al. 1651 ( IBGE, SPF) GoogleMaps ; idem, 01 July 2000, Munhoz et al. 1721 ( IBGE, SPF) GoogleMaps ; idem, 01 July 2000, Munhoz et al. 1729 ( IBGE, SPF) GoogleMaps ; idem, 19 July 2000, Munhoz et al. 1764 ( IBGE, SPF) GoogleMaps ; idem, 19 July 2000, Munhoz et al. 1797 ( F, IBGE, SPF) GoogleMaps ; idem, 16 August 2000, Munhoz et al. 1831 ( F, IBGE, SPF) GoogleMaps .