Drosera ascendens Saint-Hilaire (1826: 268)

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 : 20-21

2. Drosera ascendens Saint-Hilaire (1826: 268) . Figures 6a, 9c–e

Lectotype (designated here):— BRAZIL. Minas Gerais: Serra de Curumatahy dans le District des Diamans [Serra de Curimataí (Buenópolis) in the Distrito Diamantino], s.d. [September 1817 according to protologue], Saint-Hilaire B1-1988 (lectotype P-578094!; isolectotypes P-578098!, P-00672083!, B-100272061!).

≡ Drosera adscendens A.St. -Hil. ex Planchon (1848: 195) nom. inval. (orthographical variant)

Perennial, forming columns up to 12.5 cm long. Leaves semi-erect, with circinate vernation, lanceolate, abaxial leaf surface densely covered with white eglandular trichomes; petioles only slightly shorter than the lamina (longer than 1/3 of leaf length), adaxial petiole surface glabrous, margins revolute; stipules rectangular in outline, apical third fimbriate. Scape with curved base (ascending). Scape, pedicels and sepals densely covered by long (up to 1.8 mm long) red glandular trichomes, increasing in size and density towards the base of the scape. Flowers with petals ca. 8 mm long, pink; gynoecium 3-carpelate, styles bifurcated at the base, ca. 4 mm long. Seeds ellipsoid, testa reticulate (based on Gonella et al. 2014).

Illustrations: — Gonella et al. (2014: 14, fig. 6—habit and details).

Distribution: — Brazil (Southeast: MG), endemic. Found in central Minas Gerais (Fig. 6a), D. ascendens was previously only known from the northern portion of the Diamantina Plateau ( Gonella et al. 2014) , but new records extended its distribution further North along the Espinhaço Range, in the municipalities of Olhos D’Água and Itacambira (E. Gomes & A. Peres, pers. comm.).

Habitat: —Seasonally wet to moist areas in campo rupestre vegetation, in sandy soils, between 730–1300 m a.s.l.

Phenology: —Collected with flowers between July to September, with sparse individuals found in flower in November.

Conservation status: —Endangered (EN) B1ab(iii)+2ab(iii). Drosera ascendens presents a restricted occurrence (EOO= 931 km 2; AOO= 32 km 2), and although it can be found inside the recently created Sempre-Vivas National Park, it is threatened by reduction of habitat quality and habitat loss by cattle ranching, invasive grasses and anthropogenic fires. Furthermore, this and other campos rupestres endemic species are severely threatened by climate change, which may dramatically reduce the suitable area for this vegetation type in the next few decades ( Fernandes et al. 2014, Barbosa & Fernandes 2016), posing a threat to habitat quality, number of locations and population size. It was previously considered as DD by Gonella et al. (2014), but new data from specimens and field observations support the conservation status proposed here.

Notes: — Drosera ascendens belongs to the D. villosa species affinity, which was recently revised by Gonella et al. (2014). According to that work, the species is distinct from all other members of the affinity by the lanceolate leaves with petioles only slightly shorter than the lamina, adaxial petiole surface glabrous, abaxial leaf surface densely eglandular-pilose, curved (ascending) base of the scape (Fig. 9c), the scape, pedicels and sepals densely covered by long glandular trichomes (Fig. 9d), comparatively larger petals and styles (Fig. 9e), and ellipsoid seeds.

The species was only recently rediscovered ( Gonella et al. 2014), 188 years after being described by SaintHilaire (1826). Before that, the name D. ascendens was mistakenly adopted in previous works ( Rivadavia et al. 2003, Rivadavia 2005, 2009) and by carnivorous plant enthusiasts when addressing the morphologically similar D. latifolia . Drosera ascendens was considered a synonym of D. villosa by Diels (1906) and in all subsequent taxonomic treatments until its re-establishment by Gonella et al. (2014).

Planchon (1848) incorrectly used the spelling “ D. adscendens ” when referring to this species, which was followed by Eichler (1872) in Flora Brasiliensis . The name represents an orthographical variant (typographical error) and hence constitutes an invalid name under Art. 61 ( Turland et al. 2018).

A small number of seeds of D. ascendens were found in herbarium specimens, while none were observed in situ or in cultivated specimens. In situ observations by PMG and AF also revealed a high clonal reproduction of this species through root sprouts. Further investigation is needed to better understand the reproduction biology of this species.

Specimens examined:— BRAZIL. Minas Gerais: Diamantina, Inhaí , July 2010, Peres Júnior 27 ( UB) ; ibid., 05 September 2011, Gonella et al. 462 ( SPF, BHCB) . Buenópolis, Parque Nacional das Sempre Vivas, 04 September 2011, Gonella et al. 454 ( BHCB, P, RB, SPF), Gonella et al. 455 ( SPF) , Gonella et al. 460 (M, MO, RB, SPF) ; ibid., 08 March 2013, Gonella et al. 603 ( SPF) , Gonella et al. 607 ( SPF) , Gonella et al. 612 ( SPF) ; ibid., 03 September 2014, Gonella et al. 734 ( SPF) , Gonella et al. 742 ( SPF) , Gonella et al. 746 ( SPF) ; ibid., 04 September 2014, Gonella et al. 752 ( SPF) , Gonella et al. 753 ( SPF) .