Mucuna tapantiana N.Zamora & T.M.Moura

Zamora, N.A. & de Moura, T.M. 2014. Mucuna tapantiana (Fabaceae: Faboideae: Phaseoleae), a new species from Costa Rica. Kew Bulletin 69: 9490. DOI https://doi.org/10.1007/s12225-014-9490-4

Type

Type: Costa Rica, Cartago, Parque Nacional Tapanti, bosque tropical lluviosopremontano, 1300 – 1700 m, 26 Oct. 1983, fl., fr., I. Chacón et al. 1546 (holotype CR!; isotypes: INB!, K!, MO!).

Morphology General Habit

Liana; stems very sparsely hirsute when juvenile, glabrous when old; stipules c. 0.4 cm long, pubescent, deciduous

Morphology Leaves Petiole

Petioles 2.6 – 9 cm long, cylindrical, glabrous; pulvinulus 5 – 8 mm long, cylindrical, glabrous; rachis 1 – 2 cm long, glabrous; stipels absent; petiolules 5 – 6 mm 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 cm, all leaflets obtuse or rounded at the base, acuminate or cuspidate (acumen 10 – 16 mm) at the apex, with appressed hairs and very sparsely hirsute on both surfaces when juvenile, essentially glabrous on both surfaces when mature, glossy on upper surface when fresh, with 3 main ascending veins and conspicuous reticulate tertiary venation

Morphology Reproductive morphology Inflorescences

Inflorescence axillary, pendent, pseudoracemose; peduncle 70 – 95 cm long, filiform; rachis 2.5 – 4 cm long, densely to sparsely appressed-sericeous, with 10 – 15 (– 20) flowers (1 – 3 at each node), the nodes spirally arranged, the internodes 2 – 4 mm long; bracts deciduous (not seen); pedicels 3.5 – 8.5 cm long, filiform, sparsely and minutely appressed-sericeous

Morphology Reproductive morphology Flowers Corolla

Corolla green or yellowish green; standard petal 2.7 – 4.1 × 1.7 – 2.0 cm, elliptic to elliptic-oblong, glabrous, concave or boat-shaped, the margins involute, with a cordate base and an acute to obtuse, emarginate apex, the claw 7 – 12 mm long; wing petals 2.5 – 3.0 × 0.9 – 1.0 cm, narrowly oblong, base attenuate, apex rounded, margins ciliate at the base, the claw c. 10 mm long; keel petals 4 – 4.5 × 0.8 – 1.0 cm, narrowly oblong-sigmoid, base attenuate, apex falcate and obtuse, the claw c. 10 mm long Flowers 4 – 4.5 cm long; calyx green, campanulate, 10 – 14 × 12 mm, densely appressed-seríceous on the inner and outer surfaces; lobes 4, the adaxial (upper) one obtuse, formed by two connate sepals, the abaxial (lower) sepals 3, unequal, the longest one (4 –) 5 – 7 mm long, the two shorter ones 2 mm long, the apex acute or rounded

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens, diadelphous (with 9 stamens fused and one free); filaments 3.6 cm long; anthers ovate to oblong, 2 – 3 mm long, basifixed

Morphology Reproductive morphology Flowers Gynoecium

Gynoecium 4 – 4.5 cm long; ovary 8 – 9 mm long, sessile, oblong, densely yellowish-hispid, 2-ovulate; style 3.8 cm long, sparsely hirsute, glabrous near the apex; stigma capitate

Morphology Reproductive morphology Fruits

Fruit oblong or ovate-oblique, 7 – 15 × 4.5 – 5 cm, base obtuse to very long-attenuate (up to 3 cm long) due to abortion of the proximal seed (when pod 1-seeded), apex acute or acuminate, constricted between the seeds (when pod 2-seeded), adaxial margin concave and undulate (or deeply undulate) at both ends (when pod 1-seeded) or deeply undulate-concave (when pod 2-seeded), abaxial margin concave and smooth (when pod 1-seeded) or shallow undulate-concave (when pod 2-seeded), somewhat laterally compressed but biconvex, smooth, densely and softly villous on outer surface, with no urticating trichomes, yellowish green or dark greenish brown when fresh turning dark brown or blackish when dry

Morphology Reproductive morphology Seeds

Seeds 1 – 2 per pod, 3.0 – 4.0 × 2.2 – 3.0 cm, oblong, laterally compressed, black

Note

Mucunatapantiana is diagnosed by its small, essentially glabrous, abruptly acuminate and trinerved leaflets; filiform peduncles 70 – 95 cm long; inflorescence rachis 2.5 – 4 cm long, with few [10 – 15 (– 20)] flowers; filiform pedicels 3.5 – 8.5 cm long; green or yellowish green flowers 4 – 4.5 cm long, with the wing petals shorter than the keel petals; fruits densely soft villous, dark brown on the outer surface (yellowish green, greenish or yellowish when fresh), lacking urticating trichomes, 1 – 2-seeded; and seeds oblong and laterally compressed. The epithet refers to the locality where the species was first collected and from where most collections come. Morphologically, Mucunatapantiana belongs to a small group of species within the neotropical members of the genus that have flowers with the wings petals shorter than the standard petals. Related species with this character are M. argyrophyllaStandl., M. holtonii (Kuntze) Moldenke, M. mollis (Kunth) DC. and M. monticola N. Zamora, T. M. Moura & A. M. G. Azevedo. However, M. argyrophylla, M. holtonii, and M. mollis all have leaflets with the abaxial surface densely pubescent (rather than glabrous or essentially glabrous in M. tapantiana), and M. monticola differs by its fruits with the surface conspicuously and irregularly lamellate or reticulate-ridged and with urticating hairs (rather than smooth and without urticating hairs in M. tapantiana).

Distribution

Mucunata pantiana is an endemic species to Costa Rica (Map 1).

Ecology

Mucunata pantiana has been collected at elevations of 1200 – 1700 m, mainly from Parque Nacional Tapantí, on the Caribbean slope of the northern Cordillera de Talamanca, in the upper basin of the Río Grande de Orosi, in rain forests near the Park headquarters. Only one collection is known from JardínBotánico José Maria Orozco of the Universidad de Costa Rica, San José, on the Pacific slope, where it appears to grow wild.

Conservation

Although Mucunatapantiana is known from Protected Areas, the species is endemic to Costa Rica, and is uncommon in the field. The Extent of Occurrence (EOO = 336.51 km2) and Area of Occupancy (AOO = 12 km2) according to IUCN (2001) criteria lead us to assess M. tapantiana as an endangered (EN) species.

Phenology

Flowering from August to October; fruiting from February to March.