Thinouia obliqua Radlk.
Creators: name: Medeiros, Herison
name: Acevedo-Rodríguez, Pedro
name: de Carvalho Lopes, Jenifer
name: Forzza, Rafaela Campostrini
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Sapindales
Sapindaceae
Thinouia
Thinouia obliqua

description: 5.Thinouia obliquaRadlk., Sitzungsber. Math. - Phys. Cl. Königl. Bayer. Akad. Wiss. München. 8 (3): 282. 1878
Figs 11, 12, 13 D
Type.
Peru • 1875, Ruiz and Pavón 916 (lectotype, designated here: MA [MA 813132] [image!], isolectotypes: B †? [F-Negative 239294] [image!], F [V 0438017 F] [image!], F [V 031742 F] [image!], FI [FI 004651] [image!], G [G 00008259] [image!], MA [MA 813131] [image!], MA [MA 813133] [image!], MA [MA 817669] [image!], MA [MA 817670] [image!]).
Description.
Tendrilled liana, up to 40 m long (fide Mexia 6675); stem cylindrical-striate or 4–5 sulcate, 10–12 cm diam., pubescent, densely lenticellate, rounded and ferruginous; cross-section simple when young or with neo formations when mature. Leaves trifoliolate; stipules minute, ca. 1 mm long, tomentose; petioles 1–6.5 cm long, terete, striate, pubescent; terminal petiolule 0.1–1.1 cm long, lateral petiolules 0.1–1.1 cm long; leaflets with the adaxial side glabrescent or puberulous, puberulous or pubescent in the veins, the abaxial side glabrescent, puberulous or pubescent, puberulous or pubescent on the veins; the leaflet secondary venation craspedodromous; secondary veins (4) 5–6 pairs, subalternate or alternate, spacing irregular, domatia present in abaxial surface of secondary vein axils; intersecondaries present; tertiary veins alternate percurrent; margins dentate-serrate, with (6) 7–12 teeth on one side, reduced to inconspicuous glands; terminal leaflet 4.9–13.6 × 2.9–5.8 cm, elliptic-ovate or ovate-rhomboidal, symmetrical or asymmetrical, the apex acute to acuminate, mucronate, the base rounded to obtuse, sometimes slightly decurrent; lateral leaflets 3.6–11.1 × 1.8–7 cm, ovate, asymmetrical, the apex acute to acuminate, mucronate, the base truncate to rounded. Thyrses axillary or terminal, umbelliform, 2–5 cm long; peduncle 1–3 cm long; secondary peduncle subsessile or 0.1–0.6 cm long; cincinni numerous, peduncle of cincinnus 0.4–0.8 cm long, pubescent. Flower 4–5.5 mm long, pedicel 1.5–2.5 mm long, pilose or pubescent; sepals 0.5–1 mm long, deltoid, villous on both surfaces; petals 1.7–2.2 mm long, spatulate, clawed, glabrous or villous; petal appendages 0.7–1 mm long, shorter than the petals, bifid, distally bifurcated, villous; nectary disc annular, glabrous. Staminate flowers with stamens 6–7, 2–3.5 mm long, the filaments villous on lower half, the anthers papillose, glabrous or pilose; pistillode 0.5–1 mm long, villous. Pistillate flower with staminodes 6–7, 1.5–2 mm long; pistil 3.5–4.5 mm long, the ovary glabrous, the stigma and styles villous. Fruits chartaceous, 3.5–5.5 × 2.3–2.7 cm; accrescent pedicel 3.4–5 mm long; stipe ca. 2 mm long; seed locule subglobose; epicarp glabrous or with sparse trichomes; cavity of seed locule with simple or capitate, ferruginous trichomes; capitate trichomes with uniseriate stalk and multicellular terminal cells. Seed 6–6.7 × 5.5 mm, ellipsoid or subglobose, glabrous.
Distribution and habitat.
Thinouia obliqua is known from Tropical and Subtropical Moist Broadleaf Forests, between 140–1000 m in the Amazon basin in western Brazil, Bolivia, Colombia, Ecuador and Peru (Fig. 13 D). Flowering from October to May, and fruiting from January to August.
Notes.
Although our phylogenetic reconstruction suggests that T. obliqua and T. myriantha belong to different clades, these two species are vegetatively similar and are partly sympatric. Nevertheless, T. obliqua is differentiated by the long-spatulate petals, 1.7–2.2 mm long; petal appendages that are shorter than the petals, 0.7–1 mm long, bifid and distally branched; and stamens 6–7 (vs. small obdeltoid petals, ca. 0.7 cm long; petal appendages longer than the petals, 1–1.5 mm long, bifid and not branched distally; stamens 8). In addition, stems in T. obliqua present neo formations, simple in T. myriantha.
In the protologue for T. obliqua, Radlkofer (1878) mentioned that the material used in the description was collected by Ruiz and Pavón 916 in Peru. Of the ten duplicates of this collection known to us, we are selecting a duplicate at MA [MA 813132] as lectotype because it is more representative.
Popular name.
Macote, Macote Negro (Peru), Pacaguasca (Ecuador).
Conservation status.
Thinouia obliqua occurs in the Western Amazon and possesses a broad EOO of 1,000,444.55 km 2 and an AOO of 104.00 km 2. It is protected by several conservations units, such as the Reserva Extrativista do Cazumbá-Iracema in the state of Acre (Brazil), Parque Nacional Natural Tinigua in the Department of Meta (Colombia), and Los Amigos Biological Station in the Department of Madre de Dios (Peru). Thus, T. obliqua should be regarded as Least Concern (LC).
Selected specimens examined.
Bolivia. Beni • Prov. Ballivián, Río Beni above confluence with Río Quiquibey, 320 m, 22 May 1990, Daly et al. 6570 (US). La Paz • Prov. Franz Tamayo, Serranía de Chepite, 700 m, Killeen et al. 3825 (LPB, F, MO, US). Brazil. Acre • Mun. Brasiléia, Rio Acre, 22 Mar 1998, Daly et al 9727 (MO, NY, UFACPZ) • Mun. Bujari, Riozinho do Andirá, 21 Jan 2018, Medeiros et al. 3328 (RB, SPF, UFACPZ) • Mun. Mâncio Lima, Parque Nacional da Serra do Divisor, 6 Dec 2022, Medeiros et al. 4884 (INPA, NY, RB, SPF, UFACPZ, UPCB) • Mun. Manoel Urbano, Parque Estadual Chandless, 180 m, 3 Apr 2019, Medeiros et al. 3810 (NY, RB, SPF, UFACPZ, US) • Mun. Sena Madureira, RESEX Cazumbá-Iracema, 3 Jan 2019, Medeiros et al. 3792 (RB, SPF, UFACPZ, US). Colombia. Meta • Centro de Investigaciones Ecológicas La Macarena, Apr 2000, Stevenson 2144 (NY). Ecuador. Los Rios • Bet Quevedo and Naranjal, 90 m, 7 Nov 1934, Mexia 6675 (F). Napo • 5 km of Las Sachas, 300 m, Baker et al. 5993 (QAME, QCNE, MO, NY) • Yasuní Forest Reserve, 240–310 m, 29 Jun 1995, Acevedo-Rodríguez and Cedeño 7577 (F, MO, US) • Estación Científica Yasuní, 200–300 m, 8 Nov 1997, Romoleroux and Baus 3200 (QCA, US) • Parque Nacional Yasuní, 200–300 m, 21 Jan 1998, R. J. Burnham and A. Krings 1569 (QCNE, F, MICH, US) • Estación Biológica Jatun Sacha, 450 m, 17 Feb 1988, Cerón 3657 (QCNE, MO, US) • Aguarico. Reserva Etnica Huaorani, 240 m, Aulestia 3367 (QCNE, MO, US). Zamora-Chinchipe • Nangaritza Cantón, Parroquia Zurmi, 1000 m, 13 Dec 2001, Clark et al. 6466 (QCNE, US). Peru. Ayacucho • Río Apurimac Valley, near Kimpitiriki, 400 m, 10 May 1929, Killip and Smith 22969 (F, NY). Cuzco • Prov. Convención, Echarate, 900 m, 3 Feb 1939, Sork et al. 10496 (F). Huánuco • Vicinity of Tingo María, 10 Aug 1959, Mathias and Taylor 3991 (F, USM) • Ca. 30 km, SW of Pucallpa-Tingo María road, 300 m, Gentry and Diaz 58605 (F, MO, NY, USM). Junín • Between Azupizu and Santa Rosa, 650 m, 28 Jun 8 Jul 1929, Killip and Smith 26139 (NY) • Puente Perene, 600 m, 9 May 1961, Schunke-Vigo 4104 (MO). Pasco • Prov. Oxapampa, Carretera Oxapamapa-Paucartambo, 730 m, 11 Jun 2003, Rojas et al. 1147 (HOXA, MO, USM). San Martín • Prov. Chazuta, Río Huallaga, 260 m, Apr 1935, Klug 4058 (F, MO, NY) • Prov. Juan Jui, Alto Río Huallaga, 400–800 m, Apr 1936, Klug 4293 (F, NY, USM) • Prov. Pachiza, Río Huayabamba, 1 Aug 1959, Mathias and Taylor 3980 (F, USM) • Prov. San Martín, Quebrada Mamonaquinha to junction with Río Mayo, 250 m, 25 May 1986, Knapp et al. 7405 (MO, USM) • Saposoa, Monte Real, 400 m, 7 Jul 1958, Woytkowski 5065 (MO). Ucayali • Middle Ucayali, Boca de Yarina, s. d., Tessmann 3500 (NY) • Purús, Río la Novia, 22 Feb 2002, Schunke-Vigo and Graham 14868 (MO, USM).
description: Published as part of Medeiros, Herison, Acevedo-Rodríguez, Pedro, de Carvalho Lopes, Jenifer & Forzza, Rafaela Campostrini, 2025, Taxonomic revision and phylogenetic relationships of Thinouia (Sapindaceae), a neotropical genus, pp. 207-273 in PhytoKeys 252 on pages 207-273, DOI: 10.3897/phytokeys.252.129621