New species of Paullinia (Sapindaceae) from continental tropical America

Abstract Six new species are described in the large Neotropical genus Paullinia (Sapindaceae), P.cidii, P.decorticans, P.fruticosa, P.hondurensis; P.martinellii and P.wurdackii. In addition, they are illustrated and contrasted to the morphologically most similar species currently known. The new species were discovered while working on a forthcoming revision of the genus.


Introduction
While working on a revision of the Neotropical genus Paullinia, we discovered several species new to science. Paullinia is one of the largest genera of Sapindaceae with more than 200 species. A recent taxonomic paper establishes Paullinia as monophyletic and related to other genera of the Neotropical tribe Paullinieae (Acevedo- Rodríguez et al. 2017). These species although not yet placed in a phylogenetic system, are sufficiently distinct as to be considered new to science. These are here described and contrasted to species considered their closest relatives due to their overall morphological similarities.

Materials and methods
The descriptions of the new species are based on herbarium collections, field notes and photographs taken by the senior author. The recognition of the new species is based on comparative morphological studies that have shown consistent morphological uniqueness (two or more characters) correlated with a particular geographical area and or habitat. Descriptions of the new species follow the format used for the family in our previous publications, ongoing floristic treatments and monographic studies of the genus (Acevedo-Rodríguez and Somner in prep.). Herbarium acronyms given for the studied collections follow Index Herbariorum (Thiers continuously updated). Preliminary conservation status of the new species was assessed by using IUCN guidelines (2001).
Distribution and ecology. Known only from the state of Amazonas, Brazil in non-flooded (terra firme) forest < 100 m elevation.
Phenology. Collected in flower from May to July and in fruit in June. Discussion. Paullinia cidii is vegetatively similar to P. bipinnata, P. filicifolia and P. hondurensis by the characters mentioned in the diagnosis. Other species with similar fruits as those found in P. cidii include P. carpopoda Cambess. and P. olivacea Radlk. However, the leaves in P. carpopoda are 3-jugate (partially bipinnate), much larger and have entire margins (vs. smaller and serrate in P. cidii) while, in P. olivacea, they are 5-pinnate and the leaflets are much larger.

Distribution and ecology.
Known from NW Amazonia, in Ecuador and Peru in non-flooded, dense forest 140-400 m elevation.
Phenology. Collected in flower in May, December and January and in fruit from December to January.
Etymology. The specific epithet refers to the defoliating bark and epidermis of leaf axes present in the new species.
Conservation status. Although Paullinia decorticans is known from few collections, they come within an EOO of ca. 80,000 km 2 , which include the Yasuní National Park and densely forested areas within Loreto, Peru. Given the low level of threats associated with this vast region, this species is here treated as least concern (LC) within IUCN guidelines.

Paullinia fruticosa
Distribution and ecology. Known from SW Amazonia, in Peru and the state of Acre in Brazil, in non-flooded, dense forest 100-500 m elevation.
Phenology. Collected in flower from August to November and in fruit from October to December and June.
Etymology. The specific epithet refers to the shrubby habit of the new species. Conservation status. Known from ten collections within an EOO of 150,000 km 2 , in moist forest understorey in the south-western Amazon region. Although this species is known only from few collections, its conservation status is here treated as least concern (LC) due to its occurrence within Manú National Park in Peru.   Discussion. Paullinia fruticosa is the only species in the genus that is consistently described in collection labels as a shrub. Other species of Paullinia (e.g. P. cuneata Radlk. and P. dasystachya) may present a shrubby habit but only during early stages but later developing into lianas. In addition, Paullinia killipii. was originally described as a shrub, based on mixed collections including Killip & A.C. Smith 27876 and 28876, which are referable to P. fruticosa. As seen in several collections, P. killipii develops as a liana that grows into the forest's canopy. These three species also differ from P. fruticosa by the presence of winged fruits. 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).
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 km 2 . 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. 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(Radlkofer , 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 martinellii
Conservation status. Known from three collections from two localities with an EOO of ca. 3,000 km 2 in the Municipality of Oriximiná in the state of Pará, Brazil. The new species seems to be rare and, because of its small known EOO, it is here treated as vulnerable (VU)  Diagnosis. Paullinia wurdackii differs from P. ingifolia Juss. by the lanate or lanatetomentose stems and inflorescence axes (vs. tomentose or tomentulose), the oblonglanceolate, ovate or deltate bracts 9-15 mm long that enclose the cincinni (vs. deltate, 1-2.5 mm long, not enclosing the cincinni), the ovate-lanceolate bracteoles 4-5 mm long (vs. deltate, ca. 1 mm long) and the sessile, depressed-globose capsules (vs. long stipitate, globose or trigonous-globose).
Description. Liana 20-25 m long. Stem terete, ferruginous lanate or lanatetomentose, becoming glabrous and lenticellate with age, producing abundant milky sap; cross section simple, up to 10 cm diam. Stipules early deciduous, leaving a scar 7-10 mm wide. Leaves imparipinnate with 1 basal pair of trifoliolate pinnae and 2 or 3 pairs of simple lateral leaflets (thus with 11 or 13 ultimate leaflets); petiole and rachis winged; petiole 10.5-23.5 cm long, wings 0.4-0.8 cm wide; rachis 7-14 cm long, wings 0.4-0.7 cm wide, puberulent; lower pair of trifoliolate pinnae with winged petiolules 1.4-1.8 cm long; leaflets 13.5-16 × 3.8-4.5 cm, coriaceous, oblong, oblong-elliptic or less often oblanceolate, discolorous, abaxially papillate; cuneate at base on distal leaflet, acute, obtuse, attenuate or sometimes asymmetrical on lateral leaflets, obtusely acuminate to caudate at apex with margins remotely serrate on distal third to half of the  deciduous stipules; and unwinged, woody fruits. Paullinia wurdackii however, is easily recognised by its lanate or lanate-tomentose stems and inflorescence axes, the large bracts and overlapping bracteoles that enclose the cincinni and the sessile fruits. While P. ingifolia has a wide distribution that ranges from Costa Rica south to Bolivia, P. wurdackii is restricted to the NW region of the Amazon basin.