Mucuna tapantiana N. Zamora & T.M. Moura, Kew Bull.

De, Tânia M., Lewis, Gwilym P., Mansano, Vidal F. & Tozzi, Ana M. G. A., 2018, A revision of the neotropical Mucuna species (Leguminosae-Papilionoideae), Phytotaxa 337 (1), pp. 448-450 : 448-450

23. Mucuna tapantiana N. Zamora & T.M. Moura, Kew Bull. , 69(1)–9490: 1, f. 1A–N, 2A, B. 2014. ( Fig. 25 )

TYPE:— COSTA RICA. Cartago. Tapanti , bosque tropical lluvioso premontano, 1300–1700 m, 26 October 1983 (fl./fr.), I. Chacón et al. 1546 (holotype: CR; isotypes: INB, K!, MO!) .

Liana. Leaves 3-foliolate; petioles 2.6–9.0 cm long; pulvinulus 5.0–8.0 mm long; stipels absent; rachis 1.0–2.0 cm long; terminal leaflet blade oblong, elliptic, ovate to ovate-elliptic, 7.5–15 × 3.2–5.5 cm, lateral leaflet blades ovate-oblong, asymmetrically-oblong or asymmetrically-ovate or ovate, 5.5–11 × 2.5–5.0 cm, all leaflets obtuse or rounded at the base, acuminate or cuspidate at the apex, the hairs appressed and very sparsely hirsute on both surfaces of juvenile leaflets, essentially glabrous on both surfaces when mature, upper surface glossy when fresh,

A REVISION OF THE NEOTROPICAL MUCUNA SPECIES

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the venation with 3 main ascending veins and conspicuous reticulate tertiary venation. Inflorescence axillary, pseudoracemose; peduncle 70–95 cm long; rachis 2.5–4.0 cm long; bracts caducous (not seen); pedicels 3.5–8.5 cm long; internodes 2.0–4.0 mm long. Flowers 4.0– 4.5 cm long; calyx 10–14 × 12 mm, densely sericeous on inner and outer surface; 4-lobed, the adaxial formed by two connate sepals, the abaxial sepals 3, unequal, the longest one (4.0–)5.0–7.0 mm long, the other two lobes 2.0 mm long, the apex acute or rounded; corolla green, or yellowish green; standard elliptic to elliptic-oblong, 2.7–4.1 × 1.7–2.0 cm, glabrous, acute to obtuse, emarginate apex and cordate base, the claw 7.0– 12 mm long; wings narrowly oblong, 2.5–3.0 × 0.9–1.0 cm, apex rounded, base attenuate, margins ciliate at the base, the claw ca. 10 mm long; keel petals narrowly oblong-sigmoid, 4.0–4.5 × 0.8–1.0 cm, base attenuate, apex falcate and obtuse, the claw ca. 10 mm long. Stamen filaments ca. 3.6 cm long. Gynoecium 4.0– 4.5 cm long; ovary 8.0–9.0 mm long; style ca. 3.8 cm long, sparsely hirsute, glabrous near the apex, stigma capitate. Fruit oblong or ovate-oblique, 7.0–15 × 4.5–5.0 cm, apex acute or acuminate, base obtuse to long- attenuate (up to 3 cm long) due to abortion of the proximal seed (when pod 1-seeded), constricted between the seeds (when pod 2-seeded), adaxial margin deeply undulate-concave and abaxial margin shallow undulate-concave (when pod 2-seeded), adaxial margin concave and undulate (or deeply undulate) at both ends and abaxial margin concave and smooth (when pod 1-seeded), somewhat laterally compressed but biconvex, smooth, densely and softly villous on outer surface, with no irritant trichomes, yellowish green or dark greenish brown when fresh and turning dark brown or blackish when dry. Seeds 1–2 per pod, 3.0–4.0 × 2.2–3.0 cm, globose, laterally compressed, black; hilum circling almost the entire circumference of the seed.

Taxonomic notes:— Mucuna tapantiana is easy to recognise by its small, glabrous, and abruptly acuminate, tri-nerved leaflets, its green or yellowish green flowers, the filiform peduncle and pedicels, and usually 1-seeded fruits which are densely and softly villous, lack irritant trichomes and turn dark brown or blackish when dried. Mucuna chiapaneca is morphologically similar to M. tapantiana (see comments under M. chiapaneca ). In M. tapantiana the wing petals are shorter than the standard petal (a character also seen in: M. argyrophylla , M. chiapaneca , M. globulifera , M. jarocha , M. holtonii , M. mollis and M. monticola ). Mucuna argyrophylla , M. globulifera , M. holtonii , M. jarocha , and M. mollis differ in having a denser indumentum on the abaxial surface of their leaflets and fruits not ornamented by lamellae (vs. abaxial surface of leaflets glabrescent and fruit surface slightly ornamented in M. tapantiana ). Mucuna monticola differs from M. tapantiana in having its leaflet surfaces strigulose adaxially and its fruit surface with conspicuous, sometimes irregular, reticulately ridged lamellae (vs. inconspicuous diagonal lamellae all with the same orientation, i.e. not forming a reticulate pattern in M. tapantiana ).

Phenology:— Flowering August to October; fruiting in February and March.

Distribution and habitat:— The species is endemic to Costa Rica, and known mainly from the Parque Nacional Tapantí, on the Caribbean side of the country ( Fig. 10 ), at higher elevations of the Río Orosi watershed, in rain forests near the Park headquarters. A single collection is known from the Jardín Botánico José Maria Orozco of the Universidad de Costa Rica, San José, where it appears to grow wild. It occurs between 1200 and 1700 m.

Conservation status:— Mucuna tapantiana is here re-assessed as being of Least Concern (LC). This updates the assessment by Zamora & Moura (2014) who concluded that the species was Endangered. Although M. tapantiana is known from a restricted area in Costa Rica (EOO= 336.51 km 2, EN; AOO= 12 km 2, EN), it occurs mainly in a National Park, and no recent decline of the population has been reported.

Representative specimens examined:— COSTA RICA. Cartago: Tapantí , bosque tropical lluvioso premontano, 1300–1700 m, 26 October 1983 (fl./fr.), I.A. Chacón et al. 1546 ( CR, INB, MO) . San José: San Pedro , Jardín Botánico José María Orozco de la UCR, 5 March 1985 (fr.), L.J. Poveda & Agustín 3956 ( CR, F, MO) ; Cantón de Turrialba, 7 km N of La Suiza on the road to Pacayitas. wet forest, 9°52'N, 83°35'W, 1200 m, 8 September 1990 (fl.), J.C. Solomon 19257 ( INB, MO) ; Cantón de Paraíso, P. N. Tapantí, cuenca del Río Reventazón, Valle de Orosí , orillas del puesto de Administración , 9º45'20"N, 83º47'00"W, 1200 m, 3 September 1997 (fl.), N.A. Zamora et al. 2607 ( INB) .

Figures

FIGURE 10. Geographical distribution of five neotropical species of Mucuna: M. monticola and M. tapantiana (endemic to Central America) M. ecuatoriana and M. killipiana (endemic to South America) M. globulifera (Central and South America).

FIGURE 25. Mucuna tapantiana. A—Stem and leaves. B–Fruits. L.J. Poveda & Agustín 3956 (F). Drawn by Ana Lúcia Souza.