Drosera riparia Rivadavia & Gonella

Gonella, Paulo Minatel, Sano, Paulo Takeo, Rivadavia, Fernando & Fleischmann, Andreas, 2022, A synopsis of the genus Drosera (Droseraceae) in Brazil, Phytotaxa 553 (1), pp. 1-76 : 54

23. Drosera riparia Rivadavia & Gonella in Gonella et al. (2014: 31). Figures 7c, 19g –i

Type: — BRAZIL. Bahia: Miguel Calmon, Parque Estadual das Sete Passagens, Cachoeira do Coração , 850 m, 03 August 2012, Gonella et al. 543 (holotype SPF-208400!; isotypes ALCB!, HUEFS-217308!, MO!, P-00847862!, RB-623118!) .

Perennial, rosetted, acaulescent, rarely with short decumbent stems (columns) up to a few cm long. Leaves semierect, with circinate vernation, with long and narrow petioles that are equal to or longer than the lamina (petiole: lamina ratio of 1–2), petiole glabrous on the adaxial surface, lamina oblong to narrowly oblong; stipules rectangular in outline, apical half to third divided into three unequal fimbriate segments. Scapes erect at the base, base glabrous or glabrescent, becoming sparsely glandular-pilose towards apex; petals 4–5 mm long; petals light pink; gynoecium 3-carpelate, styles bifurcated at the base. Seeds obconic, 0.7–0.9 mm long, black, testa reticulate (based on Gonella et al. 2014).

Illustrations: — Gonella et al. (2014: 32, fig. 14—habit and details).

Distribution: — Brazil (Northeast: BA), endemic to the Chapada Diamantina (Fig. 7b).

Habitat: —Along the margins of perennial rivers, often semi-shaded by riparian vegetation, but also observed in open seepages with Sphagnum carpets, in sandy to peaty soils, and in soil-filled pockets or cracks in sandstone, between 850–1850 m a.s.l.

Phenology:— Drosera riparia has been collected in flower throughout the year.

Conservation status: —Vulnerable (VU) B1ab(iii). Drosera riparia is only known from a few small populations (AOO= 24 km 2), growing in isolated fragile environments widespread on the Chapada Diamantina. Gonella et al. (2014) considered this species Vulnerable (VU), a category that is further supported here by the calculated EOO of 5998 km 2 and threats to habitat quality, such as pollution of the rivers, incorrect management of tourism in waterfalls (habitat of the species), and climate change. It is found inside the Chapada Diamantina National Park and Sete Passagens State Park.

Notes: — Drosera riparia belongs to the D. villosa alliance ( Gonella et al. 2014), being the only representative of this group recorded in Bahia. It is promptly distinguished from other species of the alliance by long petioles relative to total leaf length (Fig. 19h), relatively small petal size, and obconic seed shape.

Specimens examined: —For a complete list, see Gonella et al. (2014: 34).