Paullinia hondurensis Acev.-Rodr. & Somner, 2018

Acevedo-Rodriguez, Pedro & Somner, Genise Vieira, 2018, New species of Paullinia (Sapindaceae) from continental tropical America, PhytoKeys 114, pp. 95-113 : 95

Paullinia hondurensis Acev.-Rodr. & Somner sp. nov. Fig. 4

Diagnosis.

Paullinia hondurensis has partially tripinnate leaves, a character that is shared only with P. bipinnata Poir., P. cidii Somner & Acev.-Rodr. and P. filicifolia Cuatrec. Paullinia hondurensis can be distinguished from P. bipinnata by the glabrous stems, inflorescence axes and calyx (vs. tomentose), as well as by the glabrous and 2-2.8 cm long capsules (vs. pubescent, 1 cm long). Paullinia hondurensis can be distinguished from P. cidii by its deltate, 2-3 mm long stipules, the nearly terete petioles and the 3-winged, trilobed-turbinate capsules (vs. subulate, 1-1.5 mm long stipules, winged or marginate petioles and unwinged depressed globose capsules). Paullinia hondurensis differs from P. filicifolia by the glabrescent stems and foliage (vs. pubescent), by the distal leaflets with obtuse apex (vs. acuminate) and by the coriaceous, obtriangular, glabrous capsules with straight wings (vs. chartaceous, ellipsoid, pubescent capsules with revolute wings).

Type.

HONDURAS. Dept. F. Morazán; [National Park La Tigra], humid and cloud forests, Rancho Quemado, Montaña La Tigra, 2000 m elev., 10 Dec 1958 (fr), A. Molina R. 8767 (holotype: US!; isotypes: EAP, MO).

Description.

Vine 4-6 m long. Stems nearly terete, striate, reddish-brown, minutely pubescent when young, glabrescent and with lines of minute lenticels when mature; cross section simple. Stipules deltate, 2-3 mm long. Leaves partially tripinnate, with triangular outline; petioles 2.2-4.5 cm long, nearly terete, adaxially bi-canaliculate, with a central pubescent ridge; rachis 6-10 cm long, marginate or with wings 1-2.5 mm wide, revolute, pubescent along central ridge; leaflets 1.6-2 × 0.6-1.3 cm, subcoriaceous, discolorous, glabrous, attenuate at base, acute or obtuse and sometimes mucronate at apex, margins serrate near the apex, distal leaflets rhomboid, lateral and basal leaflet elliptic, obovate or ovate, slightly asymmetrical at base; venation mixed craspedodromous, adaxially with prominent pubescent midvein, abaxially with midvein and secondary veins prominent and hair domatia on lower secondary axils; tertiary venation reticulate. Thyrses axillary, racemose, 4-9 cm long, with pubescent axes; bracts ca. 2 mm long subulate; cincinni shortly stipitate, 3- or 4-flowered; pedicels 2-3 mm long, articulate at middle. Sepals 5, concave, chartaceous, ciliate, the outer sepals ovate 2.5-2.7 × 1.8-1.9 mm, inner sepals sub-orbicular or obovate, 3.4-3.5 × 2.6-3.2 mm; petals oblong, unguiculate, ca. 4 × 2 mm, with glandular trichomes on adaxial surface; appendages ca. 3 mm long, crest emarginate; nectary 4-lobed, puberulent, the posterior lobes ca. 1 mm long, ovate, anterior lobes ca. 0.6 mm, elliptic; stamens unequal, free to base, 2-2.7 mm long, filament pubescent; ovary glabrous. Capsule trilobed-turbinate, 3-winged, red, 2-2.8 × 1.5-2.3 cm, coriaceous, prominently veined, with subglobose coccus, glabrous, truncate and apiculate at apex, wings dorsal-apical (on upper half portion of capsule), 4-7 mm wide, cuneate at base and with stipe 2.5-5 mm long; mesocarp ca. 0.5 mm thick; endocarp yellowish-brown tomentose. Seeds 1-3 per capsule, trigonous-obovoid, ca. 1 × 0.8 cm long, dark brown, glabrous, shiny, with bilobed arillode in lower half; embryo ellipsoid; abaxial cotyledon curve, adaxial cotyledon biplicate.

Distribution and ecology.

In moist or cloud forest between 1900-2000 m elevation.

Phenology.

Known to flower in July and to fruit in December and January.

Etymology.

The specific epithet refers to the country where the species was first collected.

Conservation status.

Known only from four localities from montane cloud forests (1990-2000 m elevation) in Guatemala and Honduras, with an approximate EOO of 11,000 km2. The type collection indicates that the species was frequent in the area, however, due to the small area of occurrence and the lack of recent collections, the species is here treated as vulnerable (VU) within IUCN guidelines.

Additional specimens examined.

GUATEMALA. Prov. Alta Verapaz. Mun. San Juan Chamelco. Montaña Caquipec, from Caquipec to Chicacnab I, 15°22'49"N, 90°10'59"W, ca. 1900 m, secondary forest and primary cloud forest, 9 Sep 1999 (st), Förther 10489 (US). HONDURAS. Dept. Lempira. Dense, mixed cloud forest on the east slopes of Quebrada Naranja, 10 km SE of Gracias, Celaque National Park, 14°33'N, 88°40'W, 1950 m, 29 Jan 1992 (fr), Thomas et al. 139 (EAP, HEH, MO, TEFH). Dept. F. Morazán, National Park La Tigra, SW of San Juancito, dense, cloud, montane forest, 2000 m, 14 Jul 1961 (fl), A. Molina R. 10120 (US).

Discussion.

We have not been able to infer the phylogenetic relationship of the new species with any other species in the genus due to the lack of adequate quality genome material. The suggested relationships with P. bipinnata , P. cidii and P. filicifolia are based on the overall morphological similarity discussed in the diagnosis. The current infrageneric classification of Paullinia based on fruit morphology ( Radlkofer 1895, 1934) would place the new species in the proximity of P. tricornis Radlk., as both species have winged, trilobed-turbinate, prominent veined capsules with subglobose cocci. However, P. hondurensis clearly differs from P. tricornis by the partially tripinnate leaves (vs. 5-pinnate).

Paullinia hondurensis is easily confused with sterile collections of Serjania rhachitera Radlk., which has tripinnate leaves with winged rachis and an overlapping distribution. However, sterile S. rachiptera can be distinguished from P. hondurensis by the sulcate stems that lack lenticels and leaflets that lack hair domatia.

Figures

Figure 4. Paullinia hondurensis. A Fruiting branch B Detail of cross section of stem C Seed, lateral view D Seed, frontal view E Fruit. All from Thomas et al. 139 (TEFH).