Mandevilla Lindl. currently includes more than 175 neotropical species and it is the largest genus of apocynoids (Morales 2011). It is distributed from Mexico to Argentina —with the exception of Chile— and the Antilles (Morales 2007a, 2007b, 2007c, 2009). It is centered in South America, with few species reaching Central America and Mexico (Morales 1998; Alvarado-Cárdenas & Morales 2004). Mandevilla is closely related to Allomarkgrafia Woodson and Mesechites Müll.Arg. but differs by its racemose inflorescences —vs. branched cymes— (Simões & al. 2004, 2006; Morales 2005a). As currently circumscribed, it is monophyletic, but the infrageneric classifications proposed to date (Woodson 1933; Pichon 1948) remain non-monophyletic (Simões & al. 2006). A new species of Mandevilla from the Brazilian Amazon basin and restricted to white sand savanna formations is described.

Mandevilla arenicola J.F.Morales sp. nov. Types: Brazil, Amazonas, estrada Terra Preta km 2, branch of Manaus-Manacapuru, 5 km from Cacau Pirêra, campin on white sand (regosol), 03º 11′ S, 55º 60′ W, 1–VII–1975, G. Prance 23535 leg. (holo-: INPA; iso-: CR, MO, NY, R). Figs. 1, 2b.

LSID: urn:lsid:ipni.org:names:77190707-1

Mandevilla arenicola sp. nov. shows an overall resemblance to Mandevilla scabra (Hoffmanns. ex Roem. & Schult.) K.Schum. but differs by its glabrous leaf blades —vs. minutely and densely tomentulose, sparsely puberulent, hirsutulous-puberulent to rarely glabrescent on the abaxial surface—, glabrous inflorescence —vs. minutely puberulent to glabrescent—, upper part of the corolla tube 23–26 mm long —vs. 13–20 mm—, and seeds 6.5–7.5 mm long —vs. 10–12 mm.

Woody vine with milky sap; branchlets terete to subterete, glabrous; interpetiolar colleters minute, up to 0.4 mm long. Leaves opposite; petioles 4–8 mm long; leaf blade 3.4–6 × 1.7–3.2 cm, elliptic to obovate-elliptic, acute-mucronulate to acuminate-mucronulate at the apex, subcordate at the base, colleters irregularly distributed along the midrib, membranaceous, glabrous on both surfaces, not revolute, secondary veins impressed on both surfaces, tertiary veins abaxially impressed, inconspicuous adaxially. Inflorescences shorter than the subtending leaves, axillary, glabrous, few-flowered, peduncle 7–11 mm long, pedicels 2.2–2.9 mm long, bracts 1.5–2.1(3) × 0.4–0.7 mm, linear to linear-ovate, scarious; sepals 2.1–2.3 × 1.3–1.4 mm, similar in length, ovate, acuminate, the apex not reflexed, scarious, glabrous abaxially, the colleter solitary, irregularly laciniate; corolla infundibuliform, yellow, glabrous, lower part of the tube 28–37 × 1.7–2 mm, the upper part 23–26 mm long, conical to conical campanulate, 14–15 mm in diameter at the mouth, the apex of the floral bud long acuminate; lobes 18–22 × 11–13 mm, obovate, somewhat reflexed marginally; stamens inserted at the base of the lower part of the corolla tube, anthers 5.1–5.3 mm long, dorsally glabrous, the base auriculate, the auricles subtruncate, style head 2.4–2.7 mm long; ovary 1.6–1.8 mm long, glabrous; nectary annular, slightly 5-lobed, ca. half of the ovary length. Follicles 12.8–14.3 cm × 1.6–2.7 mm, not fused longitudinally, sometimes only united at the apices, glabrous, continuous to obscurely articulated; seeds 6.5–7.5 mm long, inconspicuously and minutely puberulent, coma 1.9–2.5 cm long, tannish yellow.

In Costa Rica 28 genera and 75 species of Bignoniaceae have been reported, including 4 endemic species (Burger & Gentry 2000; Morales & Jiménez 2009; Zuntini & al. 2015). In the phylogenetic study of Lohmann (2014), almost all the taxonomical implications derivated were published, but several combinations at the varietal level need to be validated. Two of these concerning to the treatment of Bignoniaceae for the Manual of Plants of Costa Rica project are published here.

Bignonia aequinoctialis var. hirtella (Benth.) J.F.Morales comb. nov. Bignonia sarmentosa var. hirtella Benth., Bot. Voy. Sulphur: 128 (1845), basion. Types: Nicaragua, Chinandega, Realejo, s.d., R. Hinds s.n. leg. (lecto-, here designated: K000449689; isolecto-: K000449688).

LSID: urn:lsid:ipni.org:names:77190708-1

Tanaecium pyramidatum var. tomentosum (Bureau & K.Schum.) J.F.Morales comb. nov.; Paragonia pyramidata var. tomentosa Bureau & K.Schum., Fl. Bras. 8: 182 (1896), basion. Type: Brazil. Minas Gerais: Uberabá, no chapadão na Faxa Formigas, 19º 41′ S, 47º 48′ W, 18–X–1848, A.F. Regnell III 48 leg. (lecto-, here designated: S17-46332).

LSID: urn:lsid:ipni.org:names:77190709-1

The cosmopolitan Clethra L. includes ca. 78 species (González-Villareal 1996, 2006). In Costa Rica eigth species are reported —all of Clethra subsect. Cuellaria (Ruiz & Pav.) DC.—: Clethra consimilis Sleumer, Clethra costaricensis Britton, Clethra formosa E.Alfaro & J.F.Morales, Clethra gelida Standl., Clethra hondurensis Britton, Clethra lanata M.Martens & Galeotti, Clethra pyrogena Sleumer, and Clethra talamancana C.W.Ham., including two endemic —Clethra formosa and Clethra talamancana— and two more restricted to Costa Rica and western Panama —Clethra consimilis and Clethra pyrogena— (Morales & Alfaro 2006). A new species endemic to Costa Rica, which resembles Clethra licanioides Standl. & Steyerm. and Clethra vicentina Standl. is described and illustrated.

Clethra secazu J.F.Morales sp. nov. Types: Costa Rica, San José, zona protectora Cerros de Escazú, bosques secundarios y robledales alterados en la falda sur del Alto Hierbabuena, 09º 50′ 24″ N, 84º 07′ 12″ W, 24–IX–1993, J.F. Morales, E. Lépiz and V.H. Ramírez 1762 leg. (holo-: CR-201143; iso-: CR, MO, MO-193925). Figs. 3, 4.

LSID: urn:lsid:ipni.org:names:77190710-1

Clethra secazu sp. nov. resembles Clethra vicentina but differs by its petioles 18–34 mm —vs. 7–15 mm—, leaf blade (3.5)4.5–7.5 cm wide —vs. 2.5–3.5 cm—, racemes (11)14–25(28) cm —vs. 12–15 cm—, sepals 2.5–3 mm long —vs. 3.5–4 mm—, and petals 2.5–3 mm long —vs. 5–6 mm.

Trees 6–20 m, bark cream, reddish brown to tannish brown, branchlets minutely and sparsely pubescent when young, the indument cream to brown, glabrate when old. Leaves with petioles 1.8–3.4 cm, green, inconspicuously and sparsely puberulent to glabrate; leaf blade 8.5–15 × (3.5)4.5–7.5 cm, bicolorous, coriaceous, broadly elliptic, elliptic to obovate, the apex obtuse to rounded or acute, the base obtuse to rounded, not infolded, entire, very sparsely puberulent on the adaxial surface, green adaxially, densely glaucous tomentulose abaxially, the indument compound of minute, stellate, and adpressed cream hairs —only visible with amplification—, mixed with few, stellate, acicular, and irregularly distributed reddish hairs —visible without amplification—, the midvein with the indument very sparsely to glabrate abaxially, with 10–13 pairs of secondary veins, impressed and evident on both surfaces, tertiary veins slightly impressed abaxially, inconspicuous adaxially. Inflorescences panicules with 5–12 racemes, (11)14–25(28) cm, many-flowered, densely tomentulose, the indument compound of minute, stellate, and adpressed cream hairs —only visible with amplification—, mixed with few, stellate, acicular, and irregularly distributed reddish hairs —visible without amplification—; bracts 2.9–3.5 × 0.5–0.7 mm, linear elliptic, shorter than the subtending pedicels, densely tomentulose, early deciduous; pedicels 3–5 mm, slender, somewhat curved; floral buds obovoid; sepals 2.5–3 × 1.1–1.4 mm, ovate-elliptic to ovate, the apex acute to obtuse, reddish brown, tomentulose on the abaxial surface, glabrous on the adaxial surface; petals 2.5–3 × 1.7–2 mm, free, obovate, entire, glabrous on the abaxial surface, with a line of hairs adaxially, inconspicuously ciliolate; filaments filiform, 0.7–0.8 mm, flattened; anthers sagittate, 0.7–0.9 mm; ovary tricarpelate, 1.2–1.4 × 1.2–1.5 mm, densely sericeous, style 0.6–0.8 mm. Fruits 0.5–0.6 × 0.4–0.5 cm, tomentulose, seeds oblong, flat.

Weinmannia L. comprises ca. 160 species distributed in the tropics and subtropics (Rogers 2002; Morales 2010a; Fuentes & Rogers 2010). In the New World, it is more diverse in the Andes, with few species present in Mexico and Central America (Harling 1999; Morales 2005b, 2010b). During the preparation of the Cunoniaceae for the Flora Mesoamericana, several specimens from Honduras with leaves with more than 17 leaflets and subentire to slightly crenate leaf blade were provisionally included in Weinmannia fagaroides Kunth by Morales (2010b). After field work in the last five years and the study in detail of preserved flowers, the material from Honduras is proposed as a new species.

Weinmannia abstrusa J.F.Morales sp. nov. Type: Honduras, Lempira, Norte Río Arcágual, filo al N del Campamento Arcágual, 13 km al SO de Gracias, Parque Nacional de Celaque, 14º 34′ N 88º 41′ W, 15–V–1992, D. Mejía 100 leg. (holo-: MO-254327; iso-: CR, EAP, TEFH). Fig. 5.

LSID: urn:lsid:ipni.org:names:77190711-1

Weinmannia abstrusa sp. nov. resembles Weinmannia fagaroides, but it is separated by its leaves 19–25 foliolate —vs. 7–15–foliolate—, rachis wing 1.9–2.2 mm wide —vs. 2.7–3.2 mm wide—, and calyx lobes 0.6–0.7 mm —vs. 1–1.4 mm—, with the apices acuminate —vs. acute.

Trees (1)8–30 m, young branchlets minutely and densely puberulent, glabrescent with age. Leaves compound, with 19 to 23(25) leaflets; leaf blade 5–7 × 3.2–4.1 mm, obovate-elliptic to obovate, mostly obtuse to rounded at the apex —the terminal leaflet acute—, obtuse to rounded basally, sessile, membranaceous, usually glabrous on both surfaces, but the midvein with few dispersed hairs along the proximal half on the abaxial surface, the distal half slightly crenate, not revolute; rachis very sparsely puberulent on both surfaces, with the indument more dense on the nodes, winged, wings 1.9–2.2 mm wide; petioles 3–4 mm, not winged, minutely and densely puberulent, stipules 3–6 mm, broadly ovate to suborbicular, early deciduous. Inflorescences 5–6.5 cm long, the rachis sparsely puberulent, pedicels 1–2.2 mm long, inconspicuously and sparsely puberulent to glabrescent; calyx lobes 0.6–0.7 mm long, inconspicuously and sparsely puberulent to glabrescent, apices acuminate, petals not seen, early deciduous, ovary 1.1–1.3 mm long, glabrous. Capsules not seen.