Peperomia tubericordata G.Mathieu, 2017

Mathieu, Guido, 2017, Peperomia tubericordata (Piperaceae), a new geophytic species from Oaxaca, Mexico, Phytotaxa 313 (3), pp. 293-295 : 293-295

Peperomia tubericordata G.Mathieu , sp. nov. ( Fig.1 ).

Geophytic species belonging to Peperomia Ruiz & Pav. subg. Tildenia (Miq.) Miq. ex Dahlst. , that can be differentiated from all other species of that subgenus by the orbicular to reniform, cordate, generally non-peltate leaves.

Type:— MEXICO. Oaxaca, mun. Pluma Hidalgo, dist. Pochutla, Cerro Espino, E of the coffee plantation ‘Monte Cristo’, on rocks, rare, 15°52’N 96°24’W, 1250 m, 2 Oct 1988, A. Campos 2476 (holotype: MEXU!).

Delicate, geophytic, lithophytic herb, 4–5 cm tall, entirely glabrous. Tuber underground, ca. 5 mm diam., globose, rooting from the apex. Leaves 4–8 per plant; petiole slender, up to 3 cm long, directly originating from the tuber; lamina membranous, translucent, orbicular to slightly reniform or ovate, 2–3 cm diam., apex rounded or obtuse, base cordate, basal lobes sometimes overlapping, or rarely peltate 1–2 mm from the base, 5(–7)-palmatinerved, the most lateral pair of nerves faintly visible and running into the lobes. Inflorescences 4–8 simple spadices per plant; peduncle up to 3 cm long, slender, directly originating from the tuber; rachis 4–6 cm long, usually twice as long as the peduncle, filiform, erect but apically bending, loosely flowered; floral bracts orbicular, centrally peltate, margin slightly undulate, obscurely clear dotted; stamens 2, filament 0.1–0.2 mm; pistil 1, ovary ovoid, style dome-shaped, stigma apical. Fruit ellipsoid, sessile, centrally attached at the base, pericarp granulose, style conical.

Etymology:— The specific epithet refers to a unique combination of features in subgenus Tildenia : the presence of a tuber combined with the presence of orbicular to reniform, cordate, usually non-peltate leaves.

Relationships:— Peperomia tubericordata exhibits the typical morphological characters of subgenus Tildenia : the presence of an underground tuber combined with leaves and inflorescences directly originating from it. However, non-peltate leaves are rather exceptional in this subgenus. They can only be found in P. parvisagittata G.Mathieu & Pino from Peru and Bolivia, and P. putlaensis G.Mathieu , which also occurs in the state of Oaxaca, but both these species have deltoid leaves.

Phenology:— The plant is above ground at least between August and October.

Distribution and habitat:— The two known collections are from ‘Cerro Espino’ in southern Oaxaca, Mexico, although the reported elevations are quite different. The species is likely rare and restricted to a moist and deep shady habitat, as is apparent from its delicate habit and the mention on the specimen labels. Elevation of occurrence at least 650–1250 m.

Paratype:— MEXICO. Oaxaca, Cerro Espino, coffee plantation ‘Calvario’, on moist rock and caves, 650 m, 28 Aug 1917, B. Reko 3379 ( US!).

Figures

FIGURE 1. Peperomia tubericordata A. general habit; B. part of fruiting rachis.