Pombalia strigoides (Taub.) Paula-Souza, Phytotaxa

Paula-Souza, J., Lima, A. G. & Souza, V. C., 2021, THE VIOLETS OF THE BRAZILIAN SAVANNA: A REVISION OF THE POMBALIA LANATA COMPLEX (VIOLACEAE), WITH DESCRIPTIONS OF TWO NEW SPECIES, Edinburgh Journal of Botany 78 (357), pp. 1-32 : 22-25

5. Pombalia strigoides (Taub.) Paula-Souza, Phytotaxa 183(1): 11, f. 1F, 3G, 5B (2014).

– Hybanthus strigoides Taub., Bot. Jahrb. Syst. 21: 445 (1896).

Type: Brazil. “ Goyaz. Auf Chapadao der Morro do Salto ”, ix 1892, E.Ule 2752/58 (lectotype HBG! [ HBG506559 ], designated by Paula-Souza in Paula-Souza & Ballard, 2014; isolectotype P!, R!) . Figures 1C , 9A–D , 10A–E .

Suffrutescent herb, 8–20 cm high, branched from a well-developed, bud-bearing underground root-like system, erect; internodes 2.5–16.5 mm. Stipule c.1 × c. 0.6 mm, margin entire; leaves alternate, sessile and usually adpressed to the stems; blade 4–7.9 × 1.5–3 mm, narrowly elliptic to elliptic, oblong, less frequently linear, apex acute, frequently obtuse or slightly acuminate, margin entire, base acute to obtuse, strigose, sometimes the hairs condensed at midrib, hairs simple, closed-pressed. Flowers purple, blue or lilac with a yellow or white spot at the base of the anterior petal, rarely white, solitary, axillary; pedicel 6.8–16.5 mm, strigose; bracteoles c.1 × c. 0.4 mm; sepals subequal, 3.6–6.7 × 1.1–2.4 mm, lanceolate, frequently subfalcate, margin entire, base truncate or rounded, strigose; posterior petals 4.7–6.5 × 1.3–2.7 mm, narrowly oblong, oblong-lanceolate or less frequently ovate; lateral petals 9.5–14 × 2.7–7 mm, oblong, frequently constricted at the central portion, or clawed, falcate, sparsely villous; anterior petal 14.5–17.5 × 16–22 mm, including a claw 4.7–6.8 mm long, transversely oblong, obtriangular, apex slightly to deeply emarginate, smooth, villous; filaments 0.8–1.2 mm, connective appendages hyaline, 1–1.2 mm long, nectar glands noduliform, rarely much reduced, inserted on the filaments or near the base of the anthers, villous; style 3 mm, glabrous, sigmoid, ovary 1.1–1.8 mm, villous to strigose. Capsule 6 × c. 6 mm, ovoid; seeds c.3 × c. 2.5 mm.

Etymology. The epithet refers to the plant’s resemblance to species of the parasitic genus Striga Lour. (witchweed) in the Orobanchaceae .

Distribution and habitat. Pombalia strigoides is restricted to campos rupestres, grasslands and savannas of Chapada dos Veadeiros region, northeastern Goiás state, Brazil (see Figure 3 ).

Phenology. The species has been collected with flowers and fruits from September to November, with a single flowering record in August.

Conservation status. Although there are records of Pombalia strigoides populations within the limits of conservation units, the species has nonetheless a restricted distribution in a region marked by the conversion of natural ecosystems into agricultural areas. According to IUCN (2012) criteria B1b(i,iii) +2b(ii,iii), this species is considered Critically Endangered (CR) based on its limited distribution (AOO, 8 km 2; EOO, not measurable) and the continuing decline in the quality of its habitats.

Selected specimens examined. BRAZIL. Goiás: Alto Paraíso de Goiás, Rod. GO-118 em direção a Cavalcante , c. 20 km N (em linha reta) de Alto Paraíso, 13°57′40.2′′, 47°28′26.1′′, 1516 m a.s.l., 23 x 2012, Paula-Souza et al. 11341/715 ( ESA, HUEFS, MBM, RB) ; Chapada dos Veadeiros, 27 km de Alto Paraíso / Colinas , campo limpo acima da Mata Funda, 24 xi 1994, M. A. Silva et al. 2398 ( IBGE) .

Typical forms of Pombalia strigoides are easily distinguished by their very reduced leaves 4–7.9 × 1.5–3 mm, which are usually adpressed to the stems, and by the strigose indument of vegetative and floral parts.

Figures

Figure 1. Scanning electromicroscopic images of the indument in species of the Pombalia lanata complex: A and B, Pombalia lanata; C, P. strigoides (from Paula-Souza & Ballard Jr., 2014, and reproduced with the permission of the copyright holder, Magnolia Press); D and E, P. velutina.

Figure 3. Distribution of Pombalia cristalina, P. insignis, P. poaya, P. strigoides and P. velutina.

Figure 9. A–D, Pombalia strigoides: A, habit; B, habitat; C, configuration of the androecium around the gynoecium (an, anther; ca, connective appendage; gl, nectar gland; pp, posterior petal; st, style); D, detail of flowering branch; E–G, Pombalia velutina: E, root system (bud indicated by arrow); F, flowering branch of congested inflorescence; G, detail of broad, fimbriate sepals (arrow). Photographs by Juliana de Paula-Souza.

Figure 10. A–E, Pombalia strigoides: A, habit; B, gynoecium; C, variation of size and shape of the corolla; D, calyx; E1, posterior stamen; E2–E4, variation of size, indument and shape of connective appendage of anterior stamens. F, Pombalia cristalina Paula-Souza, sp. nov.: anterior stamen. Drawn from Gifford & Fonseca 243 (A), Irwin et al. 9355 (B and E3), Rizzo 8407 (C1, D, E1 and E2), Heringer 2503 (C2 and E4) and Proença & Oliveira 1562 (F) by Rogério Lupo.