Thinouia cazumbensis H. Medeiros
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 cazumbensis

description: 1.Thinouia cazumbensisH. Medeiros, PhytoKeys 165: 118. 2020.
Fig. 6, 13 A
Type.
Brazil. Acre. • Mun. Sena Madureira, Reserva Extrativista do Cazumbá-Iracema, Núcleo Cazumbá, castanhal coletivo, 20 July 2018, H. Medeiros et al. 3401 (holotype: RB!, isotypes: INPA!, SPF!, UFACPZ!, US!).
Description.
Tendrilled liana, 6–8 m long; stem puberulent, with yellowish to whitish indumentum, lenticellate; cross-section simple, cylindrical. Leaves trifoliolate; stipules ca. 2 mm long, linear, triangular to lanceolate, hirsute-tomentose; petiole 2–8.5 cm long, canaliculate; terminal petiolule 1.2–1.7 cm long, tomentose or tomentulose, lateral petiolules 0.2–0.8 cm long; leaflets glabrous on both sides, the secondary venation eucamptodromous but distally craspedodromous; secondary veins 7–8 pairs, subalternate or alternate, spacing irregular, sometimes with domatia on abaxial secondary vein axils; intersecondaries present; tertiary veins reticulate; margins entire to dentate-serrate, with 2–4 teeth reduced to inconspicuous glands, ciliate; terminal leaflet 12–13 × 6.5–7.5 cm, oblong, the apex acute, mucronate, the base truncate or rounded to obtuse; lateral leaflet 9.5–11.5 × 4.8–5.7 cm, oblong or ovate-rhomboidal, the apex acute, mucronate, the base truncate or rounded. Thyrses axillary, racemiform, 8.5–16 cm long; peduncle 1.1–2.8 cm long; rachis 7.5–16 cm long; cincinni numerous, sessile. Flowers ca. 2 mm long, pedicel ca. 0.5 mm long; sepals ca. 1 mm long, connate at the base, lobes ovate, acute, glabrous and with prominent veins on the adaxial surface, abaxial surface villous; petals ca. 1.5 mm long, obovate, obtuse, not clawed, glabrous on the central part and villous on the margins; appendages rudimentary, ca. 0.3 mm long, bifid, shorter than the petals, adnate to central portion of petal, villous; nectary disc glabrous, 5 - lobed, the lobes ca. 1 mm long. Staminate flower with stamens 8, ca. 1.5 mm long, the filaments villous for more than half of their length, the anthers glabrous; pistillode ca. 1.5 mm long. Pistillate flower with staminodes ca. 1 mm long; pistil ca. 1.5 mm long, the style villous, the ovary puberulent. Fruits ovate, chartaceous, 5–5.5 × 2–2.3 cm; stipe 2–3 mm long; seed locule slightly subglobose, 1.2–1.4 × 1.1–1.4 cm; epicarp densely strigose, with simple and capitate trichomes on cocci, strigose on wings; cavity of seed locule glabrous. Seeds trigonous-ovoid, ca. 6 × 4 mm, basally attached, glabrous.
Distribution, habitat and phenology.
Thinouia cazumbensis is known from the type and from a collection from the state of Pará, Brazil, in non-flooded tropical and subtropical moist broadleaf forests. It occurs in the Reserva Extrativista do Cazumbá-Iracema where it is an infrequent liana that reaches the canopy of the open ombrophilous forest with abundant bamboo (Guadua spp.) (Fig. 13 A). Collected in flower during July and September, and in fruit in July.
Notes.
Thinouia cazumbensis is differentiated from most species of Thinouia by the racemiform thyrses (Fig. 6 B) and the 5 - lobed nectary disc, a character recorded for the first time in the genus (Fig. 6 E).
Conservation status.
The species is still only known from a single locality each in Acre and Pará and it is categorized as Data Deficient (DD) according to IUCN (2022). Further field studies are needed to evaluate its conservation status more accurately.
Additional specimen examined.
Brazil. Pará • Rio Jarí, Monte Dourado, terra firme forest, 17 Sep 1968, N. T. Silva 1022 (IAN, US).
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