Piptolepis pseudomyrtus (A. St.-Hil.) Schultz Bipontinus (1863: 64)

Cândido, Jacqueline B. & Loeuille, Benoît, 2022, Reestablishment of the name Piptolepis pseudomyrtus (Vernonieae, Asteraceae), Phytotaxa 531 (2), pp. 136-142 : 137-141

Piptolepis pseudomyrtus (A. St.-Hil.) Schultz Bipontinus (1863: 64) .

Vernonia pseudomyrtus Saint-Hilaire (1833: 367) .

Type:— BRAZIL. Minas Gerais: près Tapinhoancanga [Itapanhoacanga], A. de Saint-Hilaire catologue B’ 910, n° 574 (lectotype: P [P00683104], designated by Loeuille et al. (2019: 90); isolectotypes: B†, K e! [K000497136], MPU e! [MPU023508], P [P00683105, P00683106]) .

Treelet 0.70–1.4 m tall, virgate, densely branched towards apex. Stems corrugated, manicate, ochraceous, old stems terete, puberulent, light brown, leaf scars deltate. Leaves alternate, simple, spiraled, ascending, subsessile to shortly petiolate, 0.3–1 mm, pad-like leaf sheath semi-conical, 0.5–1 mm long; blade very narrow elliptic to elliptic or oblanceolate, 6–19 × 1.8–6 mm, discolorous, chartaceous, venation eucamptodromous, midrib prominent abaxially and sunken adaxially, adaxial surface dark olive green, tomentulose, with black glandular dots, abaxially light green, velutinous, margins entire, flat, apex subacute to obtuse, base attenuate. Inflorescence in terminal raceme, with leaf-like bracts at base of capitula, 8–12 × 1.5–3.5 mm, apex acute, base attenuate. Capitula 3–6, homogamous, discoid, sessile; involucre campanulate, 9–12 mm tall × 7–15 mm diam, 6–7 seriate; phyllaries weakly imbricate, scarious, margins entire, glandular-punctate, outer phyllaries triangular to narrowly triangular or lanceolate, 2.5–4.2 × 0.9–1.2 mm, apex acute, stramineous, lanulose, inner phyllaries narrowly oblong, 9–10 × 0.9–1.6 mm, apex acuminate, stramineous sometimes with reddish apex, pubescent, glandular-punctate; receptacle flat, fimbrillate. Florets 17–31, bisexual, fertile; corolla actinomorphic, deeply 5-lobed, pale lilac, glabrous, glandular-punctate, 9–11 mm long., corolla tube 5–8 × 0.5–1.4 mm., corolla lobes 3.6–4 × 0.6–0.7 mm, apex acute; anthers calcarate, white, apical appendages acute, anther base sagittate; style shaft 6–11 mm long, pale lilac, glabrous throughout except for pubescent upper 1 mm beneath style-arms, style base glabrous, lacking basal node, style arms 1.5–3 mm long, apex acute, short-pubescent outside throughout. Cypselae prismatic, 2–2.2 × 0.6–1 mm, 10-ribbed, glabrous, glandular-punctate, dark brown; carpopodium annular, minute; pappus setae biseriate, 4–6.5 mm long., subequal or equal, deciduous, stramineous, paleaceous, barbellate, tapering towards the apex ( Fig. 1 , 2 ).

Distribution and habitat: —Endemic to the Espinhaço Range in the state of Minas Gerais, the species currently occurs within the boundaries of the municipalities of Serro and Alvorada de Minas (in the Itapanhoacanga area) ( Fig. 3 ) but some historical collections from Diamantina and Ouro Preto indicate that the species may have had a larger geographical distribution. P. pseudomyrtus occurs in campos rupestres, in areas of quartzite rock outcrops in sandy and rocky soils, close to small streams, at elevations between 672 and 1,132 m a.s.l.

Phenology:—Flowering and fruiting specimens were found in April and May, and with flowers only in November.

Additional specimens examined: — BRAZIL. Minas Gerais: s.l., fr., s.d., G. Gardner 4752 (NY e!; R!, S); Serra da Lapa, s.d., Riedel 911 (K; NY e!); Diamantina , ao tombador, fl., fr., 7 April 1892, A.F.M. Glaziou 19552 (R!); Diamantina , fl., 9 May 1905, L. Damazio s.n (RB 57108!); Ouro Preto , fl. fr., s.d., L. Damazio s.n (RB 57107!); Serro , Distrito de Mato Grosso, Pedra do Cruzeiro , elev. 1,132 m, [-18.693611°, -43.458333°], fl. fr., 28 May 2001, J.N. Nakajima 3066 & R. Romero (HUFU!). Alvorada de Minas , Itapanhoacanga, trilha para a cachoeira Campina, elev. 846 m, [-18.7975°, -43.443055°], fl., 14 November 2007, M.M. Saavedra et al. 529 (RB!, SPF!, UFP!); ibid, elev. 672 m, [-18.805277°, -43.436388°], fl., 19 November 2011, B. Loeuille et al. 599 (K!, MA!, MBM!, RB!, SPF!, UFP!, US!) ; ibid, elev. 696 m, [-18.804722°, -43.436666°], fl. fr., 14 May 2019, J.B. Cândido 345 & Almir (UFP!) .

Conservation status: — Piptolepis pseudomyrtus is known from less than ten collections [According to the Reflora – Herbário Virtual (2021) and SpeciesLink (2021) databases]. An analysis with the GeoCAT tool (Bachmann et al. 2011) provides an area of occupancy (AOO) of 24,000 km 2 and extent of occurrence (EOO) of 334,189 km 2, indicating that if a formal assessment were to be carried out according to the IUCN guidelines (2021) this species would probably be classified as Endangered (EN B1a+B2a).

The closest protected area from recent collections is Serra do Cipó National Park, but all specimens were sampled outside the park area. P. pseudomyrtus occurs in relatively preserved vegetation, however its distribution area comprises areas of touristic interest such as waterfalls. Additionally, some of the collection localities are surrounded by roads and inhabited areas, which could lead to future decline in habitat quality. More attention should be given to this reestablished species, including the possibility of proposing new protected areas.

Notes:— Piptolepis pseudomyrtus differs from P. buxoides by the habit (treelet vs. shrub), leaf shape (narrowly elliptic to elliptic or oblanceolate vs. obovate), subsessile to shortly petiolate leaves (vs. sessile), larger leaves (6–19 × 1.8–6 mm vs. 6–8 × 4 mm), number of florets per head (17–31 vs. 7), prismatic cypselae (vs. cylindrical) and equal to subequal series of pappus setae (vs. unequal).

There are no record of other Piptolepis species co-occurring with P. pseudomyrtus ; however it is morphologically similar to P. schultziana Loeuille & D.J.N.Hind in Loeuille et al. (2012: 12). Piptolepis pseudomyrtus can be distinguished from P. schultziana by the leaves with eucamptodromous venation (vs. hyphodromous), fewer capitula per inflorescence (3–6 vs. 7–18), campanulate involucre (vs. cylindrical), prismatic cypselae (vs. cylindric) and shorter pappus (4–6.5 vs. 6–7 mm long). It also resembles P. ericoides ( Lessing 1831: 629) Schultz Bipontinus (1863: 63) ; however, P. pseudomyrtus differs by its leaves with eucamptodromous venation (vs. hyphodromous), higher number of florets per head (17–31 vs. 10–16) and barbellate pappus setae (vs. serrulate).

Schultz Bipontinus (1863) based his description of P. pseudomyrtus on Martius 545, a material belonging to a different species ( P. monticola ). According to Loeuille et al. (2012), Schultz Bipontinus probably did not study the type of Vernonia pseudomyrtus (Saint-Hilaire B’ 910-574) and only knew that species through Saint-Hilaire’s (1833: 94, 367) and Candolle’s (1836: 17) descriptions. However, P. pseudomyrtus was a validly published new combination, as Schultz Bipontinus correctly referenced the basionym (ICBN, Art. 41.1 in Turland et al. 2018) and the misidentification of the species does not invalidate it (ICBN, Art. 7.3, Ex. 3 in Turland et al. 2018). Besides, under his combination of P. buxoides, Schultz Bipontinus cited an additional material (Riedel 911/1824) that belongs to V. pseudomyrtus A. St. -Hil. This probably explains why Baker (1873) considered the two species synonymous in Flora brasiliensis.

Figures

FIGURE 1. Piptolepis pseudomyrtus. A. Habit. B. Leaf arrangement and pad-like leaf sheath (highlighted). C. Head. D.–E. Fruiting heads. A.–E. by J.B. Cândido.

FIGURE 2. Piptolepis pseudomyrtus. A. Virgate habit. B. Stems with leaf scars. C. Pad-like leaf sheath. D. Leaf, adaxial surface. E. Leaf, abaxial surface. F. Flowering branch with raceme. G. Head. H. Corolla, androecium and style. I. Anther. J. Style. K. Cypsela. A.–K. illustration by Regina Carvalho.

FIGURE 3. A. Brazil with the state of Minas Gerais highlighted. B. Espinhaço Range in Minas Gerais with area of occurrence highlighted. C. Distribution of Piptolepis pseudomyrtus: recent collections (black circle), 19th century collections (white diamond).