Mucuna chiapaneca M. Sousa &T.M. Moura, Phytotaxa, 2016

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

5. Mucuna chiapaneca M. Sousa &T.M. Moura, Phytotaxa : 246(3): 198. 2016. ( Fig. 7 )

TYPE:— MEXICO. Chiapas: Municipio Jitotol, along the Rio Hondo, 6.5 km North of Jitotol along road to Pichucalco , 1700 m, 27 October 1971 (fl.), D.E. Breedlove & R.F. Thorne 21422 (holotype: MEXU!, isotype: DS!) .

Liana. Leaves 3-foliolate; pulvinus 5.0–8.0 × 2.0–3.0 mm; petiole 7.0– 10 cm long; stipels persistent; rachis 2.5–3.5 cm long; petiolule 1.0 cm long; leaflet blades glabrous on both surfaces; lateral leaflets 9.0–10 × 4.5–5.0 cm, asymmetric at base, cuspidate at apex; terminal leaflets elliptic, 9.5–10 × 4.5–8.5 cm, acute at base, cuspidate at apex. Inflorescence axillary, pseudoracemose, peduncle up to 2.5 m long; bracts caducous; rachis ca. 5.0 cm long; pedicels 5.0– 6.5 cm long. Flowers 4.5–5.0 cm long; calyx reported as greenish brown (S.S. Tillett 636-67 US), 1.5 cm long, sericeous; 4-lobed, the adaxial lobe formed by two connate sepals, 5.0 × 7.0 mm, retuse at apex, lateral lobes 5.0 × 2.0 mm, acute at apex, abaxial lobe 8.0 × 3.0 mm, acute at apex; corolla reported as cream to yellow green in colour (S.S. Tillett 636-67 US); standard oval, 4.0 × 3.0 cm, truncate at base, claw 8.0 mm long; wings obovate, 3.0 × 1.0 cm, claw 9.0 mm long; keel petals oblong, 4.0 × 1.5 cm, auriculate at base, acute at apex, claw 1.0 mm long; wing and keel petals pubescent at base. Stamen filaments 4.0– 4.8 cm long, glabrous. Gynoecium ca.

A REVISION OF THE NEOTROPICAL MUCUNA SPECIES

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4.3 cm long; style 3.8 cm long, sericeous, the hairs becoming sparse at apex; ovary 12 × 3.0 mm, with a dense indumentum; stigma peltate, villous. Fruits 1 (2–3)-seeded, when 1-seeded, ovate-oblique, long attenuate at base, 7.0–8.0 × 5.0 cm, rostrate at apex, when 2–3-seeded, oblong, 11.5–14.5 × 3.6–5.0 cm, short-attenuate at base, shortly rostrate, constricted between the seeds, laterally compressed, covered with a dark brown (umber) pilose indumentum of long, ascending, soft non-irritant trichomes. Seeds (immature) 1–3 per fruit, 2.7 × 2.3 cm, globose, laterally compressed, black.

Taxonomic notes:— A strongly distinguishing characteristic of M. chiapaneca is that after flowering the corolla persists at the base of the fruits, a character not seen in any other species of the genus. Mucuna chiapaneca is morphologically similar to M. tapantiana Zamora & Moura (2014: 9490) and bears some resemblance to M. argyrophylla , especially in the colour of the corolla and the short wing petals (these usually shorter than the standard petal, especially when not including the claw length). Mucuna tapantiana and M. argyrophylla both bear nodose brachyblasts ( M. chiapaneca does not), and a peduncle up to 1.0 m long (in M. chiapaneca it is up to 2.5 m long). Mucuna chiapaneca has stipels whilst M. tapantiana does not. The flowers of M. tapantiana are slightly shorter (4.0– 4.5 cm long) than those of M. chiapaneca (4.5–5.0 cm long), and the fruits of M. tapantiana are ornamented by discrete lamellae (vs. no ornamentation in M. chiapaneca ). Mucuna chiapaneca has glabrous leaflets which readily differeniates it from M. argyrophylla which has a dense sericeous, silvery indumentum on the abaxial surface of its leaflets. Mucuna tapantiana is endemic to Costa Rica, while M. chiapaneca is endemic to Mexico.

Phenology:— Flowering June to October; fruiting in August.

Distribution and habitat:— This species is endemic to Chiapas, Mexico, on the Jitotol Ridge in the Northern Highlands of Chiapas ( Fig. 1 ). It grows in two different forest types: montane rain forest and pine-oak- Liquidambar Linnaeus (1753: 999) forest.

Conservation status:— Mucuna chiapaneca has a restricted extent of occurrence (EOO= 57.700 km 2, CR) and area of occupancy (AOO= 24 km 2, EN). Moreover, the species is reported from only a few localities in Chiapas, Mexico. Although Sousa & Moura (2016) assessed M. chiapaneca to be Endangered [(EN B1B2ab(iii)], some collection localities of the species are within undisturbed areas. Nevertheless, no specimen of M. chiapaneca has been collected from a protected area, and where the species does occur the vegetation is being degraded by the development of roads and agriculture. We here propose an amendment to the assessment made by Sousa & Moura (2016) and now consider the species to be Data Deficient (DD) based on a lack of information about habitat quality. More detailed information about the distribution of the species might necessitate a reassessment as Vulnerable or Endangered.

Representative specimens examined:— MEXICO. Chiapas: Municipio de Pueblo Nuevo Solistahuacán, Rincón Chamula , 20 August 1969 (fl./fr.) O.F. Clarke 298 ( DS, ENCB, MEXU) ; Selva Negra , ca. 3 mi N of Pueblo Nuevo Solistahuacán, 3 June 1970 (fl.) R.F. Thorne & E. Lathrop 40252 ( DS, ENCB) ; vicinity of Pueblo Nuevo Solistahuacán , 125 km NE of Tuxtla Gutiérrez, 22–30 June 1963 (fl.), S.S. Tillet 636–67 ( US) ; above Pueblo Nuevo Solistahuacán , 15 August 1967 (fl.) A.S. Ton 2833 ( DS, MEXU) ; on slopes 3 km northwest of Pueblo Nuevo Solistahuacán , 22 August 1970 (fl.), H. Zuill 276 ( DS) .

Figures

FIGURE 1. Geographical distribution of six neotropical species of Mucuna: M. chiapaneca and M. jarocha (endemic to Mexico), M. analuciana and M. japira (endemic to Brazil), M. mollis (endemic to Colombia), and M. rostrata (widely distributed in Central and South America, and the Caribbean Islands).

FIGURE 7. Mucuna chiapaneca. A—Leaf and inflorescence. B—Detail of stipels of apical leaflet. C—Detail of stipels of lateral leaflets. D—Calyx opened out, outer surface. E—Standard. F—Wing. G—Keel petals. H—Androecium with nine stamens united into a sheath (here opened out). J—One free stamen. K—Gynoecium. All drawn from: S.S. Tillet 636-67 (US), drawn by Ana Lúcia Souza.