Thinouia trifoliolata Acev.-Rodr. & Ferrucci.
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 trifoliolata

description: 12.Thinouia trifoliolata[sic, as trifoliata] (Radlk.) Acev.- Rodr. & Ferrucci., Syst. Bot. 42 (1): 111. 2017
Figs 19 C, 23, 24
Allosanthus trifoliolatus Radlk. in A. Engler, Pflanzenr. [Heft 98 f] 4, Fam. 165: 1157. 1933.
Type.
Peru • Stromgebiet des Maranon, Santiago-Mundung am Pongo de Manseriche, ca. 77°30'W, 1924, G. Tessmann 4462 (lectotype, here designated: B [2 sheets] [B 100673676, B 100673675] [image!], syntype: Peru. Stromgebiet des Maranon, Santiago-Mundung am Pongo de Manseriche, ca. 77°30'W, 1924, G. Tessmann 4444, B [B 10067362] [image!], NY! [NY 4206164]).
Description.
Tendrilled liana; stem cylindrical, striate, glabrous or puberulous, lenticels round or elliptical, sometimes with whitish or mucilaginous exudate; cross-section simple. Leaves trifoliolate; stipules <0.5 mm long; petiole 5–7 cm long, terete, glabrous or subglabrous, sometimes pulvinate at base; terminal petiolules 1.6–2.8 cm long, canaliculate, sometimes pulvinate; lateral petiolules 0.7–1.9 cm long, canaliculate, sometimes pulvinulate; leaflets glabrous on the both sides; leaflet secondary venation eucamptodromous, secondary veins 5–8 pairs, alternate or subalternate, spacing irregular, without domatia; intersecondaries present; tertiary veins mixed opposite-alternate percurrent or alternate percurrent; margin entire, sometimes serrate at the apex; terminal leaflet 7–14.5 × 3.4–7.2 cm, elliptic or oblong, symmetrical or asymmetrical, the apex acuminate, rarely rounded to retuse, with an apical gland, the base obtuse; lateral leaflets 6.8–12.5 × 3.3–6.8 cm, elliptic or oblong, the apex acuminate, with an apical gland, the base acute or obtuse. Thyrses cauliflorous, axillary or terminal, racemiform, 4–5.2 cm long; bracts ca. 2.8 mm, linear-lanceolate, pubescent, glabrescent; peduncle 0–0.2 cm long, tomentose; cincinni numerous, peduncle of cincinnus ca. 0.1 cm long, tomentose. Flower ca. 3.5 mm long; pedicel 1.5–2 mm long, glabrous to strigose; sepals ca. 1 mm long, deltate to obdeltate, abaxially strigose or glabrous, adaxially glabrous; petals ca. 1 mm long, obtrullate, not clawed, erose, ciliate along margins; appendages 0.8–1 mm long, shorter than the petal, villous; nectary disc annular, lobed, glabrous. Staminate flowers with stamens 8, ca. 3 mm long, the filaments villous on lower half, the anthers ca. 0.5 long, glabrous, papillose; pistillode ca. 0.5 mm long, villous on the apex. Pistillate flowers with staminodes 8, ca. 1 mm long, villous on lower half; pistil ca. 1.5 mm long, the ovary villous at the apex, the style and stigma villous. Fruits chartaceous, 3–5.1 × 2–2.8 cm; accrescent pedicel ca. 2 cm long; stipe 2–2.5 mm long; seed locule lenticular, sometimes the base flattened; epicarp glabrous; seed locule cavity sparsely ferruginous-pubescent, with simple, capitate and arachnoid trichomes. Seed 7.5 × 4–4.5 mm, obovoid, glabrous.
Distribution and habitat.
Thinouia trifoliolata is known from Costa Rica, Colombia, Ecuador, Peru, and Brazil (Fig. 19 C), in tropical and subtropical moist broadleaf forests at 100–320 m elevation, in dense and open ombrophilous forests. Flowering from November to February, and fruiting from December to March.
Notes.
Unlike most members of the clade in which T. trifoliolata emerges (Fig. 4) the inflorescence of T. trifoliolata is racemiform. This character is also found in T. cazumbensis, a species sympatric with T. trifoliolata, so in the absence of molecular data both species could be interpreted as closely related. However, our molecular phylogenetic analyses strongly supports that this character is homoplaseous, i. e., it evolved independently within the clades where these two species belong. Despite sharing a similar inflorescence, T. trifoliolata differs from T. cazumbensis by its lobed annular disc and sparsely ferruginous pubescent locule cavity (vs. 5 - lobbed disc and glabrous locule cavity).
The description of this species was based on two collections (Tessmann 4444 and 4462) from the same place and deposited in the same herbarium (B), however the collection Tessmann 4462 is more representative as it has flowers and complete leaflets. Therefore, we are selecting Tessmann 4462 as the lectotype.
Conservation status.
Thinouia trifoliolata possesses a broad EOO of 3,450,116.37 km 2 and AOO of 96.00 km 2, with more than 10 threat situations and records in conservation units. The EOO values and the number of threat situations approach the threshold for the inclusion of the species in a threat category. Thus, T. trifoliolata is considered as Least Concern (LC).
Selected specimens examined.
Brazil. Acre • Mun. Bujari, Riozinho do Andirá, 28 Nov 2013, Costa et al. 373 (LABEV, NY, RB) • Mun. Manoel Urbano, Parque Estadual Chandless, 20 Jan 2014, Costa et al. 468 (LABEV, NY, RB) • Mun. Sena Madureira, Reserva Extrativista do Cazumbá-Iracema, 13 Dec 2019, Medeiros et al. 4380 (NY, RB, SPF, UFACPZ). Amapá • Mun. Mazagão, Reserva Genética de Felipe, 10 Oct 1987, Rabelo et al. 3541 (INPA, HAMAB, MO). Pará • Mun. Parauapebas. Floresta Nacional de Carajás, 27 Sep 2022, Obermuller et al. 1920 (MG, NY, RB, UPCB). Colombia. Antioquia • Rain forest near Río León, 100 m, 20 Mar 1962, Feddema 1983 (MICH, NY, US). Costa Rica. Puntarenas • Carara National Park, 30–40 m, Grayum et al. 4720 (MO, NY). San José • Carara National Park, 5 Apr 1993, Gentry et al. 79454 (MO). Ecuador. Pastaza • Pastaza Cantón, Pozo petrolero Villano 2 de ARCO, 400 m, 1 Dec 1991, Hurtado et al. 2885 (US). Sucumbios • Pastaza Cantó, Pozo Reserva Faunística Cuyabero, sendero detrás de estación, tierra firme, 265 m, Apr-Oct 1988, Paz y Miño 81023 (MO). Peru. Amazonas • Prov. Bagua, Yamayakat Bosque de Rivera, 320 m, 9 Feb 1996, Jaramillo et al. 1143 (MO, US). Loreto • Prov. Requena, Cocha Iricahua, margen izquierda del Río Ucayali, 17 Feb 1982, Encarnación 1298 (NY) • Prov. Ucayali, Canchahuayo, 200 m, 30 Nov 1985, Vásquez and Jaramillo 7058 (MO, NY) • Prov. Maynas, Nauta, quebrada Saragosa, 150 m, 11 Dec 1986, Vásquez and Jaramillo 8577 (F, MO, NY) • Iquitos, Caserio Picuruyacu, 11 Feb 1976, Revilla et al. 127 (MO, USM). Madre de Dios • Prov. Tambopata, Puerto Maldonado, 26 Nov 2002, Valenzuela and Huamantupa 1063 (US) • San Martín, Juan Jui, Alto Huallaga, 400–800 m, s. d., Klug 4176 (F).
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