Paulliniacidii differs from P.bipinnata Poir., P.filicifolia Cuatrec. and P.hondurensis Acev.-Rodr. & Somner, the only three congeners with partially tripinnate leaves with triangular outline, by its globose, long-stipitate, unwinged capsules (vs. shortly stipitate, and winged). It is unique within Paullinia by having the referred combination of characters.

BRAZIL. Amazonas; Mun. Borba, [Rio Madeira], 30 km along road from Borba to Rio Mapuri; disturbed terra firme forest on clayish soil, 24 Jun 1983 (fr), C.A. Cid Ferreira 3912 (holotype: NY!; isotypes: INPA, RB-410311!, US-00842969!)

Liana or climbing shrub. Stems terete, striate, minutely ferruginous-pubescent, glabrescent, becoming dark brown to blackish with lines of reddish-brown lenticels when mature; cross section simple. Stipules subulate, 1–1.5 mm long, puberulent. Leaves partially tripinnate, with triangular outline; petiole narrowly winged or marginate, 1.6–2.5 cm long; rachis winged, 3.8–5 cm long, central ridge ciliate or glabrous, wings 1–2.5 mm wide; leaflets 6–15 × 4–8 mm, chartaceous, discolorous (abaxially lighter), glabrous or puberulent on both surfaces, sometimes abaxially glandular punctate, sessile and attenuate at base, obtuse, rounded, or truncate at apex, with dentate margins; distal leaflets rhomboid, with symmetrical base, lateral leaflets elliptic or obovate, with slightly asymmetrical base; venation craspedodromous, tertiary venation inconspicuous. Thyrses distal and paniculate or axillary and racemose, 15–32 cm long; peduncle 1.8–4 cm long; rachis 3.5–8.8 cm long, minutely appressed pubescent; bracts ca. 0.5 mm long, triangular, puberulent; cincinni 6- to 10-flowered, sessile; bracteoles ca. 0.2 mm long, similar to bracts; pedicels 0.5–0.7 mm long, articulate in lower third. Sepals 5, flavo-sericeous, concave, sub-coriaceous, ciliate, the outer sepals ovate, ca. 0.5 mm long; inner sepals obovate, 1–2 mm long; petals obovate, ca. 1.5 mm long; appendages hood-shaped, ca. 1 mm long, crest fleshy, yellow, bicorniculate in posterior appendages; nectary 4-lobed, pilose, the posterior lobes oblong-ovoid, truncate at apex, anterior lobes minute, torus pilose; sterile stamens with pilose filaments; gynoecium ca. 2 mm long, the ovary ellipsoid, sericeous-tomentose, style 0.1–0.5 mm long. Capsule depressed globose, unwinged, reddish, 5–10 × 7–12 mm, faintly 6-costate, crustaceous, flavo-puberulent, with slightly prominent vein network and a stipe 3–6 mm long; mesocarp 0.1–0.2 mm thick; endocarp glabrous. Seeds 1 or 2 per capsule, depressed globose, 5–7 × 7–9 mm, dark brown, pilose, with white, bilobed arillode in lower third; embryo depressed ovoid, cotyledons sub-straight.

Known only from the state of Amazonas, Brazil in non-flooded (terra firme) forest < 100 m elevation.

Collected in flower from May to July and in fruit in June.

The specific epithet honours Cid [Carlos A. Cid Ferreira], a functionary of INPA and prolific collector of Amazonian plants, who made the type collection.

Known from five collections from lowland, non-flooded, moist forests NE and SE of Manaus, Amazonas, Brazil. Its known distribution has an extent of occurrence (EOO) of 22,000 km². Since only a few collections are known of P.cidii, it is here treated as data deficient (DD) within IUCN guidelines.

BRAZIL. Amazonas, Rio Abacaxis, Terra Preta, terra firme forest, clayish soil, 4°22'S, 58°40'W, 5 Jul 1983 (fl), Todzia et al. 2317 (INPA, MO, NY, RB, US); Município Presidente Figueiredo, Rebio Uatumã Grade do PPBio, 22 May 2007 (fl), Zartman, et al. 7124 (INPA, US), Balbina, Rebio Uatumã, 1°00'S, 59°00'W, 15 Jul 2006 (fr), Ribeiro et al. 2660 (INPA, US), Vila da Balbina, próximo a Ilha do Jacaré, 20 Jun 2006 (fr), da Silva et al. 1207 (INPA, US).

Paulliniacidii 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.