Two new species of Handroanthus Mattos ( Bignoniaceae ) from the state of Bahia , Brazil

(Two new species of Handroanthus Mattos (Bignoniaceae) from the state of Bahia, Brazil). Two new species of Handroanthus Mattos (Bignoniaceae), endemic to Semideciduous Seasonal Forest of Bahia, are here described as H. diamantinensis and H. parviflorus. Illustrations, distribution maps, as well as a discussion about the morphological characteristics that distinguish the new species from related species are presented.


Introduction
Bignoniaceae have a Pantropical distribution and are most diverse in the Neotropics, especially South America (Gentry 1980;Lohmann 2004).The family comprises 82 genera and approximately 827 species (Lohmann & Ulloa 2007), and is currently divided into seven clades (Bignonieae, Catalpeae, Oroxyleae, Crescentiina, Tecomeae, Tourrettieae, and Jacarandeae; Olmstead et al. 2009).Crescentiina is composed of two "subclades", one exclusively Paleotropical and the other Neotropical, comprising several species traditionally included in Tecomeae.The Neotropical "subclade" contains 14 genera and 147 species, and has been given the informal name "Tabebuia Alliance" due to the high number of Tabebuia species (Grose & Olmstead 2007a;Olmstead et al. 2009) that together with Handroanthus represent about 66% of the species within the group (Grose & Olmstead 2007b).
Handroanthus displays ample morphological variability.Species in the genus have the following characteristics: an arboreal or occasionally shrubby habit; palmately compound leaves that are (3-)5-9-foliolate (rarely 1-foliolate), with simple and / or branched trichomes; inflorescences that are dichotomously branched, with poorly developed rachises many times contracted and covered in simple, stellate, or dendroid trichomes; a calyx that is coriaceous, campanulate, and mostly 5-lobed, with indumentum also composed of simple, stellate or dendroid trichomes; a corolla that is predominantly yellow (lilac in only four species), tubular-infundibuliform to tubular-campanulate, with a glabrous or tomentose internal surface; fruits that are capsular, linear-cylindrical, smooth to slightly ribbed, pubescent, glabrous or sparse-lepidote; and seeds that are bi-winged, with wings clearly demarcated from the seminiferous body.The genus comprises 30 species and is widely distributed in Central and South America, with one species, H. billbergii, (Bureau & K.Schum.)S.O.Grose occurring in the Antilles (Grose & Olmstead 2007b).
While working on the taxonomic treatment of the "Tabebuia Alliance" for the flora of Bahia State, Brazil, two new species of Handroanthus were found.These taxa are here described as H. diamantinensis and H. parviflorus.
Tree up to 30 m high; branches cylindrical to subtetragonal, slightly fissured longitudinally, pubescent, trichomes stellate and dendroid up to 2 mm long.Leaves 5(6)7-foliolate; petiole 11.8-32.4cm long, cylindrical, densely tomentose, trichomes stellate and dendroid; central petiolule 3.4-14.6cm long, densely tomentose, trichomes stellate and dendroid; leaflets 12.2-30.8× 4.6-17.3cm, elliptic to oblong-elliptic, base truncate, rounded or obcordate, apex acute to acuminate, margin entire, coriaceous, strongly discolorous, adaxial surface olive-green, glabrescent, with trichomes restricted to the main and secondary veins, abaxial surface cream-yellow, densely tomentose, with stellate and dendroid trichomes covering the whole surface; when young: membranous, margin sometimes irregularly serrated from the middle apical region, adaxial surface moss-green, abaxial surface cream-ferruginous, tomentose in both surfaces, trichomes stellate and dendroid; petiolules and leaflets progressively smaller towards the extremities.Inflorescences open panicles c. 30 × 20 cm, terminal; peduncle densely tomentose, trichomes dendroid; bracts and bracteoles 0.3-0.5 cm long, lanceolate, persistent.Flowers with pedicel c. 2.5 cm long; calyx 1.9-2.9× 1-1.6 cm, tubular, brownish-ferruginous, 2-3-lobed, irregularly partite, apex obtuse, densely villous, dendroid trichomes to 1.5 mm long, and also stellate trichomes; corolla tubularinfundibuliform, 8-8.8 cm long, floral tube 4.1-5.5 cm long, opening 2.8-4.1 cm wide, lobes 1.5-2.8cm long, yellow, with reddish striations, base fleshy and apex membranous, externally densely glandular, internally villous, trichomes simple; stamens inserted, free part of the dorsal stamens c. 1.2 cm long, free part of the ventral stamens c. 1.6 cm long, free part glabrous, adnate part tomentose, anthers glabrous, thecae c. 2.5 × 1 mm; ovary c. 8 × 3 mm, linear-oblong, not ribbed, minutely lepidote-glandular; nectarial disk annular, conspicuous; style c. 2.3 cm long, glabrous, stigma c. 2.5 mm long, glabrous, bifid.Capsules 39.3-66 × 1.5-2.3cm, linearcylindrical, brownish-ferruginous, longitudinally striated, densely tomentose, trichomes dendroid.Distribution, habitat, and conservation status -Handroanthus diamantinensis is restricted to Semideciduous Seasonal Forest in the Chapada Diamantina (Fig. 4), and is known only from the Vale do Pati, a valley with a trekking path of approximately 80 km that links the municipalities of Mucugê and Andaraí, traversing the Chapada Diamantina National Park, Bahia.In spite that the area is in a good conservation state and is legally protected, less than 10 individuals of the new species were located in the field.Considering the conspicuous flowering of the whole group, it can be inferred that the species has a punctual distribution and occurs in low frequency in the area.On the other hand, collection efforts at this locality are not intensive, and the flora is still poorly known.Since the species was collected only recently, and its only record is within a protected area, it is still premature to classify it at any level of threat.Thus, the species should be considered as Data Deficient (DD; IUCN 2001) for the assessment of its conservation status.
Etymology -The epithet refers to the area where this species occurs, which is the Chapada Diamantina, in Bahia, Brazil.
Notes -In the taxonomic treatment of tribe Tecomeae for the Neotropical region, Gentry (1992) informally subdivided Tabebuia s.l.into ten groups using vegetative and reproductive characters.Handroanthus diamantinensis is more closely related to group IV, characterized by the yellow flowers with a calyx that is densely pubescent or occasionally villous, with stellate or dendroid trichomes; leaflets with few trichomes restricted to the main vein on the abaxial surface or, more frequently, densely distributed on the whole surface; and capsules that are puberulous or villous, and covered with stellate or dendroid trichomes.Among the species of this group, H. diamantinensis is most similar to H. botelhensis, but also has morphological similarities with H. albus (Cham.)Mattos, H. vellosoi (Toledo) Mattos, and H. catarinensis (A.H.Gentry) S.O.Grose (Tab.1).It differs from H. botelhensis due to the strongly discolorous leaflets of adult plants (vs.concolorous to weakly discolorous), calyx 2-3-lobed (vs.2-5-lobed), longer corolla (8-8.8 vs. 6-8 cm), larger opening of the floral tube (2.8-4.1 vs. 2-2.5 cm), tomentose region of stamen insertion (vs.glabrous), and the bigger capsules (39.3-66 × 1.5-2.3cm vs. 21-23 × 1.3-1.4cm).Handroanthus diamantinensis can be promptly distinguished from the remaining mentioned species due to the entire margins of mature leaflets (vs.regular and conspicuously serrated), among other characters (Tab.1).The epitype was designated to help with the species interpretation because the type lacks flowers.
Distribution, habitat, and conservation status -Handroanthus parviflorus is known from a single location in Semideciduous Seasonal Forest, in the municipality of Itapé, in the state of Bahia (Fig. 4).The area is in an advanced stage of degradation, which is especially due to agriculture and cattle farming; the original vegetation is rather impoverished and reduced to small patches.Therefore, according to the criteria proposed by the IUCN (2001), H. parviflorus should be classified as Endangered [EN B1ab(iii) Etymology -The epithet refers to the reduced dimensions of floral characters in this species.