Piptolepis riparia Loeuille, Semir & Pirani, 2019

Loeuille, Benoît, Semir, João & Pirani, José R., 2019, A synopsis of Lychnophorinae (Asteraceae: Vernonieae), Phytotaxa 398 (1), pp. 448-450 : 448-450

11. Piptolepis riparia Loeuille, Semir & Pirani , sp. nov. Type:— BRAZIL. Minas Gerais: São Gonçalo do Rio Preto, Parque Estadual do Rio Preto , margem do Córrego das Éguas, 18°08’44.4”S, 43°21’57”W, 884 m, 8 February 2010, B. Loeuille et al. 516 (holotype: SPF [ SPF221000 ]; isotypes: BHCB, K, NY, P, RB, UFP, US) ( Fig. 35 G , 36 ).

Species Piptolepi imbricatae foliis anguste ellipticis ad oblanceolata et pappi setis inaequalibus simile, sed foliis magnis (7–15 × 1.8–4.5 mm, non 6.5–9 × 2.2–3.5 mm) et floribus 10–19 (non 9–10) differt.

Shrub, up to 1 m tall; branches ochreous tomentose, turning glabrescent and dark brownish with age; leaf scars triangular dark brownish, distinctive on leafless portions of stem. Leaves sessile or subsessile, pad-like sheath 0.8–2 mm long.; blade narrowly elliptic to oblanceolate, 0.7–1.5 cm × 1.8–4.5 mm, venation hyphodromous, midrib prominent abaxially, adaxially sunken, adaxial surface green, densely velutinous to subsericeous, abaxial surface dirty white, tomentose to velutinous, margin flat or slightly revolute, apex acute to obtuse, base acute to attenuate. Capitula solitary, sessile, surrounded by foliage leaves, terminal on upper branches; involucre campanulate 7.4–8.4 mm tall, 3.8–5.4 mm diam., phyllaries 5–6-seriate, stramineous, apex acute, frequently brownish; outer phyllaries triangular to narrowly ovate, 2.1–5 × 0.9–1.5 mm long, tomentose; inner phyllaries lanceolate, 5.6–7.1 × 0.9–1.2 mm long, tomentose towards apex; receptacle weakly fimbrillate, fimbriae up to 0, 1 mm. Florets 10–19; corolla lilac, glabrous, densely glandular-punctate, corolla tube 5.2–6.3 × 0.7–1 mm, corolla lobes 2.3–3.3 × 0.5–0.6 mm, apex acute; anther lilac, apical anther appendages lanceolate, acute, anther base sagittate, obtuse; style shaft 7.1–8 mm long, lilac, glabrous throughout except for pubescent upper ca. 0.7 mm beneath style-arms, style-arms 2–2.5 mm long. Cypsela prismatic, 4-angled, 1.5–1.8 × 0.5–0.9 mm, 10-ribbed, glabrous, glandular-punctate; pappus biseriate, unequal, stramineous, persistent, outer series setae 0.2–0.8 mm, subpaleaceous, erose, serrulate, inner series setae 2.2–5.2 mm, straight, setose, barbellate.

Distribution and habitat: — Brazil (Minas Gerais, endemic to São Gonçalo do Rio Preto, in the eastern side of the Diamantina Plateau). Campo rupestre; 884 m.

Conservation status: —The species is known from a single locality and population located in a protected area (Parque Estadual do Rio Preto). According to results obtained through GeoCAT analysis ( Bachman et al. 2011) (EOO = 0 km 2; AOO = 4 km 2; using a cell size of 2 km 2), the species is classified as Critically Endangered ( IUCN 2017). Nevertheless, the only known population of the species may not allow a confident evaluation of its conservation status. Thus, we suggest this species should be classified as Data Deficient (DD).

Etymology: —The specific epithet refers to the habitat of the species, which was collected on the rocky banks of the river Córrego das Éguas.

Taxonomic Notes: —To date, this species is only known from the type collection. Piptolepis riparia is similar to P. imbricata by its narrowly elliptic to oblanceolate leaves and unequal series of pappus setae, but the former species has larger leaves (7–15 × 1.8–4.5 mm vs. 6.5–9 × 2.2–3.5 mm) and a higher number of florets per head (10–19 vs. 9–10). The new species might also be confused with P. leptospermoides but that species has smaller leaves (5.5–6.8 × 1–1.5 mm) and cypsela with pilose furrows (vs. glabrous). In the Parque Estadual of Rio Preto, other three species of Piptolepis are found: P. leptospermoides , P. ericoides and P. oleaster . The latter two species are very distinct from P. riparia : P. ericoides has narrowly linear leaves and P. oleaster has large non-ericoid leaves (6.2–8 × 2–3.5 cm).

Figures

FIGURE 35. Piptolepis ericoides. A. Flowering branch. P. campestris. B. Head. P. leptospermoides. C. Head. P. monticola. D. Habit. P. oleaster. E. Habit. P. pabstii. F. Habit. P. riparia. G. Flowering branches. A., E.–G. by B. Loeuille. B. by N. Roque. C. by I.M. Franco. D. by M. Lusa.

FIGURE 36. Holotype of Piptolepis riparia Loeuille, Semir & Pirani (SPF221000).