Syngonanthus hensoldiae M.T.C.Watan. & Sano, 2016

Watanabe, Mauricio Takashi Coutinho & Sano, Paulo Takeo, 2016, Syngonanthus hensoldiae (Eriocaulaceae): another new species of S. sect. Syngonanthus endemic from Chapada dos Veadeiros, Central Brazil, Phytotaxa 253 (4), pp. 293-300 : 294-299

Syngonanthus hensoldiae M.T.C.Watan. & Sano sp. nov. Figs. 1–2 .

Syngonanthus hensoldiae is distinguished from S. nitens and S. cabralensis by the thin white roots. It also differs from S. cabralensis by involucral bracts with apex acute or round, from S. nitens by paleaceous inner most involucral bracts and brown-colored involucral bracts, this latter feature also can separate it from S. gracilis var. gracilis .

Type:— BRAZIL, Goiás: Alto Paraíso de Goiás, estrada Alto Paraíso de Goiás —Teresina de Goiás, entrada do aeroporto, em direção ao Rio dos Couros, campo limpo em área de fazenda, população densa em beira de córrego, 14°06’24.6’’S, 47°33’03.7’’W. 19 July 2012 (fl, fr), M. Watanabe & W. Watanabe 375 (holotype SPF!, isotype F!).

Perennial herbs (4.5–)9.0–26.0 cm tall. Roots white, 0.05–0.30 mm in diameter, spongy. Short stem of the rosette erect, rarely decumbent and branched, 5–20 × 0.75–3.00 mm, densely tomentose to villous, with white and woolly curled hairs. Leaves spirally arranged in rosette, patent, slightly ascending, 7.5–25.0× 0.5–2.5 mm, linear to lanceolate, apex acute to rotund, veins 4–6, adpressed filamentous trichomes on both surface, long filamentous hairs only on the abaxial midvein and abaxial margin. Inflorescences 1–7 per rosette. Spathes 1.5–3.5 cm long, chartaceous, cylindrical, erect, pilose with free filamentous and adpressed trichomes, glabrescent with age, ciliate, the upper part slightly enlarged, the apex acute, obliquely slanted and opened. Scapes erect, rarely flexuous, twisted, 3.5–24.0 cm long, golden or greenish in young plants, 3–costae, glabrous to scarcely pilose, glabrescent with age, with adpressed trichomes between the costae, sometimes a smooth collar of simple filamentous basifixed hairs near the apex. Capitula 3.5–6.5 mm in diameter, obconic at base. Involucral bracts in 5–8 series, 1.25–2.70× 0.65–1.00 mm, paleaceous in all series, the very proximal part (short base) white to translucent, hyaline, and the distal portion dark brown to castaneous, the outer series glabrous or scarcely pilose with long filamentous hairs on abaxial surface, glabrous adaxially, shortly obovate, progressively elongating toward the internal series, apex round or acute, the inner series scarcely pilose with long filamentous hairs on abaxial surface, glabrous adaxially, the innermost series subspathulate and hyaline, glabrous; receptacle discoid, pilose. Floral bracts absent. Flowers 3–merous, 60–90 per capitulum, surpassing the innermost involucral bracts by 0.5 mm; the staminate ca. twice the pistillate in number, similar in color and size. Staminate flowers 2.3–2.6 mm long including pedicels; pedicels 0.5–0.7 mm long; sepals 1.7–2.0 mm long, white, hyaline when hydrated, membranous, shortly fused at base, slightly recurved, concave, irregular-subspathulate, asymmetrical, sometimes the inner sepal is slightly oblong, apex of all sepals rotund or obtuse, adaxially glabrous, abaxially pilose with filamentous basifixed hairs on the center; corolla 0.8–1.5 mm long including the anthophore; anthophore ca. 1/3 of the corolla length; tube membranous; lobes triangular, involute after anthesis, glabrous; stamens 3, filaments adnate to the middle of the corolla, anthers ca. 0.2 mm long, cream-colored; pistillodes 3, inconspicuous, capitate, papillose at apex; anthophore and pedicel greenish even in senescent flowers or occasionally light castaneous. Pistillate flowers 1.8–2.6 mm long including pedicels; pedicels 0.4–0.6 mm long; sepals 1.8–2.0 mm long, free, ovate to lanceolate, concave, apex rotund to acute, base slightly thickened, cream to light castaneous becoming hyaline toward apex, adaxially glabrous, pilose on the abaxial surface, with free filamentous hairs, glabrescent with age; petals shorter than sepals, 1.3–1.5 mm long, oblong, lobe truncate, involute after anthesis, membranous, white to hyaline, connate just below apex, glabrous; ovary 0.6–0.8 mm long; style column 0.4–0.6 mm long, cream or cream to greenish-colored; appendages ca. 0.3 mm long, apex capitate and glandular; stigmatic branches simple, ca. 1 mm long. Seed ca. 0.60× 0.25 mm, ellipsoid, castaneouscolored with longitudinal rows of pseudotrichomes.

Etymology:— This new species is named in honor of Ph.D. Nancy Hensold, Field Museum of Natural History, for her long-lasting contribution to general identification of Neotropical flowering plants and dedication to taxonomic knowledge of Eriocaulaceae for the past thirty years.

Morphological comments:— Syngonanthus hensoldiae has white and thinner roots than S.nitens and S.cabralensis (which have castaneous and orange roots, respectively), and its roots are similar to those of S. gracilis var. gracilis . The leaves of the rosette are ascending to slightly recurved in S. hensoldiae ; but in S. nitens and S. cabralensis the leaves are recurved or reflexed (strongly reflexed in S. cabralensis ) and coriaceous. The new species has chartaceous leaves, which are less congested in the rosette than these species, being the texture and orientation of the leaves similar to S. gracilis var. gracilis . Detailed morphological comparisons among these species are listed in the table 1.

It is common to observe capitula with turbinate or obpyriform shape in younger capitula of Syngonanthus nitens and S. cabralensis , which may be due to a receptacle more thickened, with more sclerenchymatous tissue at base (N. Hensold, personal communication). Therefore, S. hensoldiae has a capitulum with not woody-thickened receptacle, and the capitulum is obconic to flattened at the base.

This new species has glabrous to pilose scapes (glabrescent with age) with trichomes only between the costae, as observed in Syngonanthus nitens . However, the trichomes are filamentous-appressed instead of long free filamentous hairs as observed in S. nitens . The scapes are also twisted as observed in S. cabralensis , but this character could be variable along the life cycle (younger scapes are more likely to be twisted) or in different specimens in the same population.

Usually, involucral bract characters are very useful to distinguish species in Syngonanthus , and S. hensoldiae has castaneous to dark brown involucral bracts in all series (except for the innermost series cream to light brown and translucent). S. cabralensis has involucral bracts with outer series brown and inner series cream, while S. gracilis var. gracilis and S. nitens have cream involucral bracts in all series. Unusually, some specimens of S. nitens and S. gracilis var. gracilis can show involucral bracts with darker coloration, but this pattern is different from that is observed in S. hensoldiae , which have the basal portion white to hyaline and the distal portion dark brown to castaneous (vs. slight castaneous in the base and cream at the apex, in the other two taxa). The innermost involucral bract is membranous in S. nitens , other contrasting character with the new species, which has paleaceous bracts. The apex of involucral bracts is also taxonomically informative and provides supports to differentiate S. cabralensis (apiculate or obtuse) from S. hensoldiae (acute or round).

Ongoing molecular studies investigating the phylogeny of Syngonanthus suggest the close relationship between S. hensoldiae and S. latifolius ( Moldenke 1971: 418) Hensold (2004: 306) (Watanabe, unpublished data). It is somewhat surprising because these species have floral morphology very distinctive. Syngonanthus latifolius has a remarkable floral dimorphism with contrasting colours and size of pistillate and staminate flowers, not observed in S. hensoldiae . So, based on morphological and molecular data, Syngonanthus hensoldiae is considered as belonging to S. sect. Syngonanthus .

Distribution, habitat and phenology:— Syngonanthus hensoldiae is endemic to the Chapada dos Veadeiros region (Goiás State, Brazil), only known from a few populations. This region is characterized by elevations ranging from 800 to 1650 m, acid soils derived from sandstone and quartzite rocks, species rich-flora, several types of vegetation, and high levels of endemism including many species of Cyperaceae , Eriocaulaceae , Poaceae and Xyridaceae ( Munhoz & Felfili 2006) .

This new species occurs in Alto Paraíso de Goiás municipality, outside conservation units, although close to the boundaries of the Chapada dos Veadeiros National Park (PNCV) ( Fig. 3 ). It is a similar pattern observed in other endemic and recently described Syngonanthus for this region, as S. incurvifolius M.T.C.Watan. & Echtern. (2015: 273) and S. vittatus M.T.C.Watan. & Echtern. (2015: 277) . Syngonanthus hensoldiae inhabits gallery forest near edge of rivers or wet, moist grasslands. Flowers and fruit of S. hensoldiae were collected during the dry season in July.

Conservation Status:— Syngonanthus hensoldiae is here considered as Endangered, according to the criteria B2ab(i,ii,iii) of IUCN (2014). Only two populations of this new species are known, both on privately owned land hosting human activities, which end to deteriorate the natural habitat.

Other specimens examined (Paratypes):— BRAZIL. Goiás ; Alto Paraíso de Goiás, 2.5 km de Alto Paraíso de Goiás em direção a Teresina de Goiás, rio dos Couros. Campo limpo sujeito a inundação dominado por gramíneas, eriocauláceas e ciperáceas, 31 July 1994, C. Munhoz & M. Ribeiro 180-b ( UB) ; estrada Alto Paraíso de Goiás / São Jorge, entrada para cachoeira São Bento, desviando pela direita, próximo ao córrego, 19 July 2012, M. Watanabe & W. Watanabe 379 ( SPF) .

Figures

FIGURE 1. Syngonanthus hensoldiae (based on Watanabe & Watanabe 375). A. Habit. B. Rosette of leaves, roots and peduncle detailed. C. Spathe with filamentous trichomes. D. Capitulum detail. E–J. Involucral bracts, from outer to inner series, respectively. K. Staminate flower. L. Staminate flower evidencing tubulose corolla. M. Staminate corolla dissected showing pistillodes. N. Pistillate flower. O. Pistillate sepals cut away evidencing three petals involute and fused at apex. P. Gynoecium.

FIGURE 2. Syngonanthus hensoldiae. A. Habit. B. Habitat. C. Involucral bracts from outer to inner series. D. Capitulum. E. Rosettes of leaves in detail. F. Staminate flower. G. Pistillate flower. H. Immature capitulum. I. Tuft of trichomes on the center of the rosette. J. White roots. Scale bars C: 2 mm. D: 1 mm. F–G: 500 μm.

FIGURE 3. Geographic distribution of Syngonanthus hensoldiae and potential area of occurrence of the morphologically related species (S. cabralensis, S. gracilis and S. nitens) in the Brazil Central and adjacent areas.