Bignonia sanctae-crucis Zuntini, 2015

Zuntini, Alexandre R., Taylor, Charlotte M. & Lohmann, Lucia G., 2015, Problematic specimens turn out to be two undescribed species of Bignonia (Bignoniaceae), PhytoKeys 56, pp. 7-18 : 13-17

Bignonia sanctae-crucis Zuntini sp. nov.

Type.

Bolivia. Santa Cruz: Prov. Ichilo. El Carmen (8 km al SSW de Buena Vista), tramo de 2km al W de la comunidad por el camino al Campamento del Río Saguayo, 17°31.98'S, 63°41.85'W, 400 m, 5 October 1996, I.G. Vargas C. 5382 & S. Hurtado P. (holotype: MO-5878679!; isotypes: K, NY!). Figure 3 .

Diagnosis.

This new species is similar to Bignonia potosina (K.Schum. & Loes.) L.G.Lohmann, but is distinguished by its membranous leaflets with mixed opposite-alternate percurrent tertiary venation (vs. chartaceous with alternate percurrent tertiary venation in Bignonia potosina ), membranous calyx (vs. chartaceous calyx in Bignonia potosina ) and fruits shorter than 6.8 cm long (vs. fruits longer than 15 cm in Bignonia potosina ). Table 2 .

Description.

Lianas. Stems solid, tetragonal, winged or ribbed, with lenticels, without interpetiolar gland field, with interpetiolar ridge, puberulous to pilose at least at nodes, sparsely lepidote; foliaceous prophylls caducous, falcate (subulate), ascending, stipitate, asymmetrical, 0.9-2.3 mm × 0.5-1.5 mm, without simple trichomes, sparsely lepidote, with a few glands on abaxial surface (no glands); bromeliad-like prophylls present. Leaves 2-foliolate; petiole semi-cylindrical, (6.1 –)15.1– 38.9 mm, pubescent, puberulous or pilose, sparsely lepidote; petiolules semi-cylindrical, 9.7-29.8 mm, pilose, sparsely lepidote; blades slightly discolorous, membranous, matte, slightly asymmetrical to asymmetrical, elliptic to widely ovate, acuminate to long acuminate apically, rounded basally (short attenuate), 8.3 –13.3(– 18.9) × 5.1 –8.5(– 12.3) cm, on adaxial surface without simple trichomes, densely lepidote, without glands, on abaxial surface pilose along midvein and secondary veins, sparsely lepidote, with a few scattered glands; venation pinnate, with tertiary venations mixed opposite-alternate percurrent; tendrils rarely present, simple, without simple trichomes, sparsely lepidote, with simple apex. Inflorescences racemes, terminal, 2-4-flowered, without simple trichomes or puberulent, sparsely lepidote, primary axis 8.3-13.8 mm long; bracts caducous, not observed; pedicels 5.5-10.0 mm, without simple trichomes, moderately lepidote. Flowers with calyx cupular, 5-toothed, membranous, 4.5-6.0 × 4.3-5.1 mm wide at apex, ciliate, moderately lepidote, with glands clustered in columns, teeth 0.6-1.5 mm; corolla creamish outside, yellowish inside, infundibuliform, dorso-ventrally flattened, membranous, 30.6-52.8 mm, externally pubescent at lobes, moderately lepidote, without glands, internally with pubescent lobes, not lepidote, with shortly stipitate glandular trichomes at base, tube 19.8-40.0 × 2.1-5.0 mm wide at base and 9.2-16.3 mm wide at apex, lobes rounded or oblong, 9.7-15.4 × 8.8-15.2 mm; androecium didynamous, with stamens included, the largest 10.7-18.0 mm, the shortest 6.4-11.7 mm, without simple trichomes, not lepidote, with shortly stipitate glandular trichomes at base, thecae 1.7-3.6 mm, staminode 0.9-2.5 mm; gynoecium 21.5-29.2 mm, ovary ovoid to cylindrical, smooth, without simple trichomes (pilose at apex), densely lepidote, ovules in 4 series per locule, style sparsely lepidote at base; nectariferous disk reduced. Fruits inflated, oblong, ca. 6.8 × 2.8 wide × 0.8 cm thick, valves woody, without ridges, smooth, without simple trichomes, sparsely lepidote, without glands. Seeds beige, thin, transversally elliptic to narrowly transversally oblong, symmetrical, 13.7-24.3 × 28.5-39.4 mm, with two opaque wings; seed body flattened, 0.8-1.2 mm thick.

Distribution.

This species is found in evergreen or semideciduous forests in Western Amazonia, occurring in Bolivia (Beni, La Paz and Santa Cruz) and Brazil (Acre, Amazonas and Mato Grosso), between 160 to 700 m alt. (Fig. 4 ).

Phenology.

This species was collected with flowers in June, September, October and November. A single fruiting specimen was collected in July.

Conservation status.

Bignonia sanctae-crucis is known from only seven locations but is considered Least Concern (LC) given its wide extent of occurrence (over 600.000 km2) and the different physiognomies where it occurs, including secondary formations. The number of locations where this species is known to occur is likely underestimated because Bignonia species are usually not densely distributed and because this entire region is not well documented floristically. Additional fieldwork is needed in order to fully document the extent of distribution of this species.

Etymology.

The epithet refers to the type locality, the Department of Santa Cruz (Bolivia), where most specimens were collected.

Discussion.

Bignonia sanctae-crucis and Bignonia potosina share quadrangular and ribbed (winged) stems, prominent interpetiolar ridges, falcate and caducous prophylls, and few-flowered racemes. Apart from being morphologically similar, these species are also closely related and can be confused. However, Bignonia sanctae-crucis can be distinguished from Bignonia potosina by the membranous calyx (vs. chartaceous in Bignonia potosina ) and fruits shorter than 6.8 cm long (vs. fruits longer than 15 cm in Bignonia potosina ) (Table 2 ). These two species are also geographically widely separated, with Bignonia sanctae-crucis found in Bolivia and central to western Brazil while Bignonia potosina is widely found in Mexico and Central America but not in South America. Bignonia sanctae-crucis can also be confused with the sympatric species Bignonia decora (S.Moore) L.G.Lohmann due to the quadrangular stems shared by both species. However, Bignonia sanctae-crucis can be recognized by its falcate and caducous prophylls (vs. foliaceous and persistent in Bignonia decora ), few-flowered racemes (vs. multi-flowered thyrses in Bignonia decora ) and fruit without ridges (vs. three longitudinal ridges in Bignonia decora ) (Table 2 ). Quadrangular stems are also characteristic of Bignonia sciuripabulum (Bureau & K.Schum.) L.G.Lohmann, a distantly related species (Zuntini and Lohmann, in prep.) that has a verrucose and glabrous ovary (vs. smooth and lepidote in Bignonia sanctae-crucis ) and echinate fruits (vs. smooth in Bignonia sanctae-crucis ); Bignonia sciuripabulum is found in Amazonia and the Atlantic forest of Brazil.

The only fruiting material of this new species (Nee 52361) was previously identified as Cydista cf. decora (S.Moore) A.H.Gentry [≡ Bignonia decora ] (in sched. at NY), a closely related species. The flowering specimens of Bignonia sanctae-crucis , however, were identified as Clytostoma sciuripabulum Bureau & K.Schum. [≡ Bignonia sciuripabulum ], Clytostoma uleanum Kraenzl. [≡ Bignonia uleana ], and some other Clytostoma species (in sched. at MO and NY). The thin-textured corolla probably confused the generic identification, given that most Cydista , as previously circumscribed, were characterized by thicker corollas whereas such thin corollas were characteristic of the previously recognized Clytostoma . Despite its corolla texture, Bignonia sanctae-crucis is not closely related to the species that were included in Clytostoma , and does not have the verrucose glabrous ovary that is characteristic of that group.

Additional examined specimens.

BOLIVIA. Beni: Rurrenabaque, Rurrenabaque, 14°28'S, 67°34'W, 333 m, 8 Oct 1921, White 874 (NY). La Paz: Alto Beni, Concesión de San Jose de Papay, 15°02'S, 67°33'W, 500 m, 23 Oct 1987, E. Vargas 2022 (LPB, MO); San Buena Ventura, 500 m, 29 Nov 1901, R.S. Williams 363 (NY). Santa Cruz: Cercado, Lomas del Rio Cúcha, 450 m, 28 Oct 1925, J. Steinbach G. 7307 (F, MO); Ibáñez, Gorge of Río Bermejo, 6.5km (by road) W of the checkpoint at Angostura, 18°10'S, 63°33'W, 690 m, 25 Jul 2003, M.H. Nee 52361 (LPB, NY, USZ). Ichilo, 2 km W of Center of San Carlos, older secondary growth along highway from Buena Vista to Villa Tunari, 17°24.5'S, 63°45'W, 310 m, 31 Oct 1999, M.H. Nee 50398 (NY); Ichilo, Estáncia San Rafaél (propiedad de la Unversidad NUR), 16 km SW de Buena Vista, 17°36'S, 63°36'W, 432 m, 1 Oct 1996, M. Saldias P. 4775 (NY, USZ). BRAZIL. Acre: Tarauacá, 1-3 km east of Rio Tarauacá, 24 Sep 1968, G.T. Prance 7513 (K, INPA, MG, MO, NY). Amazonas: Envira, Rio Juruá, Basin of Rio Jurua, near mouth of Rio Embira, 7°30'S, 70°15'W, 160 m, 28 Jun 1933, B.A. Krukoff 5046 (MICH, MO, NY, US). Mato Grosso: Barra do Bugres, Fazenda Ochsenfeld, 23 Oct 1995, G. Hatschbach 63777 (MBM, SPF).

Figures

Figure 3. Bignonia sanctae-crucis Zuntini. A Flowering branch B Stem node with prophylls of the axillary buds C Detail of the abaxial leaflet surface D Calyx E Opened flower F Ovary side-view G Ovary cross-section H Fruit I Seed. Illustrated from Vargas 5382 (NY) [A, D], Saldias 4775 (NY) [E-G] and Nee 52361 (NY) [B, C, H, I].

Figure 4. Distribution of Bignonia sanctae-crucis (red circles), Bignonia decora (blue triangles), and Bignonia potosina (green squares). Elevation in meters, following the scale on the right.