Tynanthus densiflorus M.C. Medeiros & L.G. Lohmann, 2014

de Medeiros, Maria Claudia M. P. & Lohmann, Lucia G., 2014, Two new species of Tynanthus Miers (Bignonieae, Bignoniaceae) from Brazil, PhytoKeys 42, pp. 77-85 : 79-80

1. Tynanthus densiflorus M.C. Medeiros & L.G. Lohmann sp. nov.

Type.

Brazil. Amazonas: Manaus-Itacoatiara, km 26, Reserva Florestal Adolpho Ducke, 16 Aug 1996, L.C. Procópio et al. 14 (holotype: INPA-189631!; isotypes: G!, K!, MG, MO!, NY!, RB!, SP!, U) Fig. 1A-I.

Diagnosis.

Tynanthus densiflorus differs from Tynanthus panurensis (Bureau) Sandwith by the interpetiolar gland fields (lacking in Tynanthus panurensis ), minute triangular prophylls of the axillary buds (versus foliaceous in Tynanthus panurensis ) and dense thyrses (versus lax in Tynanthus panurensis ). It further differs from Tynanthus pubescens A.H. Gentry in the leaflets with a caudate-mucronate apex (versus acuminate or obtuse-mucronate apices in Tynanthus pubescens ) and the dense inflorescences (versus lax in Tynanthus pubescens ).

Description.

Liana. Branchlets subtetragonal to terete, finely striate, with lenticels, pubescent to puberulent, with simple and peltate trichomes; interpetiolar ridge absent or present; interpetiolar glands present; prophylls of the axillary buds 0.5-0.8 mm long, 1-2.5 mm wide, minute, shallowly triangular, puberulent throughout, with simple and peltate trichomes. Leaves 2-3 foliolate; terminal leaflets modified into a trifid tendril; petioles and petiolules with a more or less conspicuous canalicule on the upper side, puberulent to glabrescent throughout, with simple and peltate trichomes; petioles 1.8-5.6 cm long; petiolules (0.6-)1.4-3.8 cm long, lateral ones with equal lengths and the terminal one longer, when present; leaflets (3.2-)5-16.1 cm long, (1.3-)2-9.5 cm wide, membranous to chartaceous (sometimes subcoriaceous), discolor or concolor, ovate, apex caudate, mucronate, base cuneate to truncate or subcordate, symmetrical or asymmetrical, margin entire; the abaxial surface pubescent to puberulent throughout (sometimes only on and near the veins), with simple, peltate and patelliform trichomes; the adaxial surface pubescent to glabrescent throughout (sometimes only on and near the veins), with simple, peltate and patelliform trichomes; glandular trichomes evenly distributed throughout both surfaces; first venation pinnate, second venation weak brochidodromous, third venation alternate percurrent (sometimes random reticulate); pocket domatia with (sometimes without) trichomes. Inflorescence 3-9.5 cm long, a thyrse, axillary, dense, corymbose to conical in aspect; axis densely pubescent to puberulent, with simple and peltate trichomes; inflorescence bracts 0.5-2.5 mm long, predominantly caducous, triangular to linear triangular, densely pubescent to pubescent throughout; floral bracts 0.4-0.6 mm long, triangular; floral pedicels 1-7 mm long. Calyx green to grayish, 1.5-2.2 mm long, 1.4-1.9 mm wide, membranous to chartaceous, with a transversal aperture, truncate or minutely 5-denticulate, densely pubescent to pubescent outside, with simple and peltate trichomes, glabrous inside; lobes 0.1-0.2 mm long. Corolla cream or pale yellow, 0.8-1.5 cm long, 0.3-0.5 cm wide at the tube opening, bilabiate, with two (almost totally fused) upper lobes and three lower lobes, densely pubescent throughout outside, with simple and peltate trichomes; tube 3-5 mm long, internally glabrous at the top, tomentose at the base, with simple, long and short stipitate trichomes; nectar guides present, yellow; lobes entire, densely pubescent to pubescent throughout lower ones and at margins of or throughout upper ones; upper ones 0.4-1.4(-2.9) mm long, 0.7-1.5(-2.4) mm wide, acute to obtuse; lower ones 2.1-4 mm long, 2-3.6 mm wide, obtuse to rounded. Androecium with four fertile stamens inserted at 1.5-2.5 mm from the base of the corolla; shorter ones 3.5-5.5 mm long; longer ones 4.5-7 mm long; filaments with long and short stipitate trichomes at the base; anther thecae cream, 1.1-1.4 mm long, obovate to elliptic, divergent and reflexed forward, glabrous, subexserted; connective extending 0.2-0.3 mm beyond anther attachment; staminode covered with long and short stipitate trichomes, 1.5-2.7 mm long. Gynoecium ca. 7-9 mm long; ovary 1.3-1.5 mm long, 0.7-0.8 mm wide, conical, velutinous, with simple trichomes, with a ring of longer trichomes at the base, with two or four series of ovules per locule; nectar disc reduced, not evident; style 5-7 mm long, tomentose at the base, with simple trichomes; stigma with lamellae lanceolate, glabrous. Fruit not seen. Seeds not seen.

Distribution and habitat.

Known from wet forests in Manaus and proximity (Amazonas, Brazil).

Etymology.

The species epithet refers to the thyrses with flowers densely arranged.

Phenology.

Flowers in August. Fruiting period is unknown.

Conservation status.

According to IUCN (2001) criteria, this species is considered Vulnerable (VU B2ab(iii)). The type collection is from a protected area (Reserva Florestal Adolpho Ducke), where a reasonable number of individuals are found (pers. obs.). Nevertheless, the proximity of Manaus can be considered a region characterized by continuous urbanization. Additional studies on distribution and abundance of Tynanthus densiflorus are still necessary in order to confirm its conservation status.

Discussion.

Tynanthus densiflorus is characterized by dense thyrses, with a corymbose to conical aspect, as well as the presence of interpetiolar glands. The type collection of Tynanthus densiflorus was treated as Tynanthus panurensis (Bureau) Sandwith for the Guide of the Ducke Reserve ( Lohmann and Hopkins 1999). Indeed, the two species are similar in the occurrence of ovate leaflets and corolla tube that is internally tomentose at base. However, the presence of interpetiolar glands in Tynanthus densiflorus (versus absent in Tynanthus panurensis ), the minute prophylls (versus foliaceous in Tynanthus panurensis ) and dense inflorescences (versus lax in Tynanthus panurensis ) allow the distinction of these taxa. Tynanthus pubescens A.H. Gentry is another species that is morphologically similar to Tynanthus densiflorus . Both taxa have similar corolla lengths (around 1-1.6 cm in Tynanthus pubescens ) and show interpetiolar gland fields; however, the caudate-mucronate leaflet apex (versus acuminate or obtuse-mucronate in Tynanthus pubescens ) and the dense inflorescences (versus lax in Tynanthus pubescens ) differentiate both taxa.

Additional specimens examined.

BRAZIL. Amazonas: 2-5 km N of Manaus-Itacoatiara Road at km 79 near Rio Preto da Eva, 100-200 m, 24 November 1974, A. Gentry 12849 (INPA, MG, MO). Rio Camanau, 28 June 1987, P. Grenand et al. 2787 (INPA). Manaus, Campus of INPA, Estrada do Aleixo, 22 November 1974, A. Gentry 12792 (INPA); 30 November 1974, A. Gentry 13018 (INPA, MO); Ibid., Transect vouchers, Line 1, 11 December 1974, A. Gentry 13181 (INPA, MO); Estrada do Aleixo near Manaus, km 6-7 past INPA, 2 December 1974, A. Gentry 13040 (INPA, MO); Reserva Florestal Adolpho Ducke, Parcela PPBio (L03 1000 m), 100 m, 02°56'03"S, 59°57'32"W, 14 December 2010, M.C. Medeiros et al. 21 (SPF); Ibid., próximo à estação meteorológica, 120 m, 02°55'37"S, 59°58'33"W, 15 December 2010, M.C. Medeiros et al. 22 (SPF); Ibid., proximidades do refeitório da base da reserva, na beira da estrada, 110 m, 02°55'59"S, 59°57'56"W, 16 December 2010, M.C. Medeiros et al. 25 (SPF).