Calea diamantinensis G.A. Reis-Silva & J.N. Nakaj., 2020

Reis, Genilson Alves Dos & Nakajima, Jimi Naoki, 2020, A new species of Calea (Neurolaeneae, Asteraceae) from the Espinhaço Range, Minas Gerais, Brazil, Phytotaxa 432 (2), pp. 199-205 : 200-204

Calea diamantinensis G.A. Reis-Silva & J.N. Nakaj. , sp. nov. ( Figs. 1 A–K and 2 A–E )

The new species is related to Calea lantanoides from which it differs by its leaf blade elliptic (vs. ovate to widely ovate), margin entire and straight (vs. crenate and revolute), surface solely glandular-punctuated (vs. villous), receptacle paleae obtrullate (vs. narrowly elliptic), capitulescence composed of 3–4 heads (vs. 6–12 heads), cypselae glandular-punctuated ca. 2.7–3 mm long (vs. non-glandular, ca. 1.8–2.5 mm long) and pappus scales ca. 15–17 (vs. 20–25).

Type:— BRASIL. Minas Gerais: Diamantina , lado esquerdo da estrada Diamantina a Conselheiro Mata, 18º16ʹ24.8ʺS, 43º42ʹ39.3ʺW, 1427 m, 11 October 2017, fl., fr., G.A. Reis-Silva et al. 289 (holotype VIC!; isotype MO!, K!, HUFU!, RB!).

Shrub perennial, xylopodial. Stems erect, 0.3–1.5 m tall, terete, slightly furrowed, glabrous at base to strigillose toward apex, sparsely glandular-punctuated, internodes 0.8–2.5 cm long. Leaves opposite, decussate, ascending, only in the apex of the branches, petiole 1–2 mm long, glandular-punctuated; blade elliptic, coriaceous, concolorous, green, 0.9–1.8 × 0.6–0.9 cm, apex rounded, base rounded, margin entire, both sides only with conspicuous glandular-punctuated trichomes, translucent, regularly scattered on surface, venation eucamptodromous. Inflorescence terminal, umbelliform, frequently with 3–4 heads, peduncles 1.4–5.4 mm long, strigillose and densely glandular-punctuated. Head discoid, homogamous; involucre monomorphic, cylindrical, 7–9.4 × 3.5–5.2 mm, phyllaries 5-seriated; outer series 2–5.6 mm × 1–2.8 mm, ovate, apex obtuse, margin ciliate, scarious, inconspicuously 5–7-striated, strigillous, slightly glandular-punctuated on upper surface to glabrous; inner series 4.8–8 mm × 2.5–3.5 mm, narrowly elliptic to elliptic, apex rounded, margin entire to slightly ciliate, scarious basally and herbaceous apically, conspicuously 6–9-striated, glabrous; receptacle convex, paleaceous, paleae 2–4, 6.7–8.6 × 1.2–3 mm, obtrullate, cymbiform, apex rounded, margin erose, entire at base, glabrous, conspicuously 3–4-striated. Florets monocline, 7–9, corollas 5.2– 6.2 mm long, tubular, yellowish, tube 2–2.6 mm long, densely glandular-punctuated, throat 2.4–3.7 mm long, non-glandular, lobes 1.5–2 mm long, lanceolate, squarrose, glabrous to slightly glandular-punctuated on upper surface; anthers yellowish, 2.3–3 mm long, apical appendage acute, glandular-punctuated abaxially; style 4.8–6.8 mm long, base dilated, branches 0.8–1.5 mm long, apex deltate with short papillae. Cypselae 2.7–3 × 1.1–1.4 mm, prismatic, 4- angled, sericeous, glandular-punctuated, carpopodium conspicuous and decurrent, pappus scales 15–17, free, 4–5 mm long, subequal, linear-lanceolate, apex aristate, margin slightly ciliate.

Additional specimens examined (paratypes):— BRAZIL. Minas Gerais: Diamantina , estrada Diamantina – Conselheiro Mata, km 187, 18º16ʹ29ʺS, 43º42ʹ46ʺW, 1405 m, 24 September 2008, fl., R. Romero 8164 et al. ( HUFU, UFG); estrada Diamantina –Conselheiro Mata, campo rupestre ao lado esquerdo da estrada, 18º16ʹ24.8ʺS, 43º42ʹ39.3ʺW, 1427 m, 11 October 2017, fl., G.A.Reis-Silva et al. 284 ( VIC); fl., fr., G.A.Reis-Silva et al 287 ( VIC, BHCB); fl., fr., G.A.Reis-Silva et al. 288 ( VIC); fl., G.A.Reis-Silva et al. 290 ( VIC); fl., fr., G.A.Reis-Silva et al. 291 ( VIC); fl., G.A.Reis-Silva et al. 292 ( VIC, TEPB); fl., fr., G.A.Reis-Silva et al. 293 ( VIC, UEC, DIAM); estrada Gouveia a Curvelo, ca. 20 km de Diamantina , 18º33ʹ36ʺS, 43º51ʹ14ʺW, 1060 m, 23 September 2008, fl., J.N. Nakajima et al. 4994 ( HUFU).

Distribution:— Calea diamantinensis is currently found only in the municipality of Diamantina , Minas Gerais State ( Figure 3 ).

Habitat:— Calea diamantinensis occurs in small populations that grow in the rocky grassland (campos rupestres) vegetation, with quartzitic rock soils of sandy texture and low capacity of water retention. The elevation varies between 1060 and 1430 m a.s.l.

Phenology:—The species flowers and sets fruit between September and October. Probably blooming in early September, after burnings that often occur in the region during August.

Conservation status:—The new species, following the IUCN criteria (2017), is considered Critically Endangered (CR; subcriterion B2a – the number of locations equals to one).

Etymology:—The specific epithet is a tribute to the historic city of Diamantina , which in 18 th century Colonial Brazil expanded in size and population due to the high production of diamonds. Today it is recognized as a UNESCO World Heritage site.

Taxonomic position and affinity:— Calea diamantinensis fits neatly into C. sect. Calea by its umbelliform capitulescences, short cypselae and long pappus scales. In the section, C. diamantinensis is more closely related to C. lantanoides , with which it shares the morphological characters as follows: subshrub erect with lignified branches, leaf blade coriaceous, discoid heads with less than 10 florets, involucre monomorphic and cylindrical, outer phyllaries ovate, receptacle paleaceous, pappus scales free and longer than the cypselae length.

The morphological characters such as perennial subshrub with lignified branches, leaf blade elliptic and coriaceous; capitulescences with 3–4 heads, involucre cylindric, 5-seriate; and corolla lobes squarrose show that C. diamantinensis also resembles C. intermedia Pruski & Urbatsch (1988: 351) . However, the latter species belongs to C. sect. Lemmatium Bentham (1873: 163) which has a pappus with 12 lanceolate scales, connate or sometimes free and not as long as the cypselae length (Pruski 1986; Pruski & Urbatsch 1988). Besides, the new species can be distinguished from C. intermedia by its leaves without non-glandular trichomes (vs pubescent), margin entire (vs. serrate), involucre monomorphic (vs. dimorphic), paleae obtrullate (vs oblanceolate), monocline florets 7–9 (vs 16–18) per head and pappus scales 15–17, longer than the cypselae length (vs. ca 12, shorter than the cypselae length).

Figures

FIGURE 1. Calea diamantinensis G.A. Reis-Silva & J.N. Nakaj. A. Habit. B. Capitulescence. C. Detail of a head. D, E, F, G. Involucral bracts. H. Paleae of receptacle. I. Corolla. J. Anthers. K. Cypselae. (All illustrations made from the holotype. Drawings by Reinaldo Pinto).

FIGURE 2. Calea diamantinensis G.A. Reis-Silva & J.N. Nakaj. A. Flowering shoot. B. Details of leaves. C. Immature head. D. Capitulescences. E. Cypselae on mature heads. Photos by G.A. Reis-Silva.

FIGURE 3. A. Location of the Minas Gerais state in Brazil. B. Location of Calea diamantinensis G.A.Reis-Silva & J.N. Nakaj. C. Threedimensional map showing part the known distribution of C. diamantinensis. Images by IBGE.