Chamaecrista celiae ( Irwin & Barneby 1978: 160 ) Irwin & Barneby (1982: 655)

Mendes, Thainara Policarpo, Souza, Alessandro Oliveira De & Silva, Marcos José Da, 2021, Taxonomic review of Chamaecrista sect. Absus subsect. Absus ser. Paniculatae (Benth.) H. S. Irwin & Barneby (Leguminosae, Caesalpinioideae), Phytotaxa 495 (1), pp. 1-64 : 15-16

1. Chamaecrista celiae ( Irwin & Barneby 1978: 160) Irwin & Barneby (1982: 655) ≡ Cassia celiae Irwin & Barneby (1978: 160) . Type: — BRAZIL. Minas Gerais: Serra Grão Mogol, n, base of mountain, 600–700 m, 16 August 1960, B. Maguire, G. Mendes Magalhaes & Celia K. Maguire 49214 (holotype: NY00003749!; isotypes: P00835980!, RB00539441!, US 00001411!). Figs. 8 and 9

Small tree 1.8–4 m tall. Stems with bark longitudinally fissured, cinereous or dark brown. Branches cylindrical, pendent, adult branches conspicuously fissured, light-brown, young branches discreetly fissured, vinaceous-brown, viscous-verrucous and pubescent, including petiole, rachis, external surface of stipules, bracts, and bracteoles, sepals, buds, ovary and fruits. Stipules 1.9−2 × 4.4−4.5 mm long, linear, persistent. Leaves 3–5.9 cm long, regularly distributed along the branches, descending or ascending; pulvinus 1.5–2.2 mm long, discreetly dilated, not striated; petiole 3.3−6 cm long, cylindrical and sulcate above; rachis 1.1–1.7 cm long, cylindrical and sulcate above; pulvinule 1–2.5 mm long, visibly dilated; leaflets (1) 2 pairs, coriaceous; blades 2.4–5.7 × 1.4–5.7 cm, orbicular or suborbicular, margin entire, plane, glabrous, surface abaxial and adaxial glabrous, base asymmetrically rounded, apex obtuse or rounded, without mucron, bluish-green, opaque; venation brochidodromous, secondary veins 6–8 pairs, yellowish. Panicles 16–49 cm long, with 6–12 secondary axis, not geminate, terminal, with flowers laxly distributed, erect to pendent, exserted from the foliage, setose-viscous including pedicel. Bracts 1.5–2.2 × 0.4–0.9 mm, lanceolate or subulate, apex acute, margin entire, vinaceous, persistent. Bracteoles 0.9–2 × 0.2–0.4 mm, subulate, apex acute, margin entire, light green, at median portion of pedicel, persistent. Buds 1–1.4 cm long, ellipsoid or more rarely ovoid, green with purplish pigmentation, apex obtuse. Flowers 2.9–4.9 cm long; pedicel 1.9–3 cm long, robust, cylindrical; sepals 1–1.7 × 0.4–0.7 cm, elliptic, apex obtuse, light green with purplish pigmentation; petals 1.6–2.8 × 0.9–3 cm, obovate, with the adaxial petal like a standard, one of the inner petals coiled in the androecium; stamens 0.5–1 cm long, filaments ca. 0.1 mm long; anthers 4–9 mm long, non-mucronulate at apex; ovary 2–4 × 1–1.1 mm, oblong, villous and glutinousverrucose; styles 0.8–1.1 cm long, glabrous. Legume 2.4–4 × 0.5–0.7 cm, oblong, green at brown glutinous-verrucose. Seeds 4 × 6 mm, oblongoid, darkish, smooth, and glossy.

Representative specimens examined: — BRAZIL. Minas Gerais: Carbonita, 200 km de Diamantina para Virgem da Lapa , 17°31’36.8”S, 43°00’56.2”W, 02 June 1967, (fl.), A. P . Duarte 10410 ( NY); Cristália, Morro do Chapéu , 16°43’00.2”S, 42°56’00.5”W, 14 June1991, R . Mello-Silva 493 ( SPF); Grão Mogol, Serra do Espinhaço , ca. 5 km ao norte de Grão Mogol, 18 February 1969, H. S . Irwin, et al. 23479 ( NMNH); ib., Vale do Rio das Mortes a oeste da Cidade, 24 July 1986, (fl., fr.), A. M . Giulietti 9882 ( HUEFS); ib., rio Itacambiruçu , próximo a barra do escurinho, 19 July 1998, (fl.), G . Hatschbach, M . Hatschbach & E . Barbosa 68060 ( MBM); ib., ao leste do município, 16°34’24.0”S, 42°53’55.6”W, 09 July 2016, (fl., fr.), T. P . Mendes, J. A . Oliveira & R. C . Sodré 284, 285 ( UFG), 286 ( UFG), 287 ( UFG), 288 ( UFG), 289 ( UFG); ib., entrada do município, 16°34’24.0”S, 42°53’55.6”W, 05 July 2017, (fl., fr.), T. P . Mendes, A. O . Souza & R. G . Matos 373, 374 ( UFG) .

Distribution and ecology:: —Endemic species of Minas Gerais and found in the Virgem da Lapa region and in the Serra do Grão Mogol (Fig. 17A), where it grows in the transition between the Cerrado and the Caatinga (Fig. 1B) in small vegetation, on soils sandy or sandstone outcrops, between 650–1000 meters elevation.

Flowering and fruiting: —Collected with flowers and fruits between the months of June and July.

Etymology: —The specific epithet “ celiae ” was named in honor of Celia Kramer Maguire , wife of the American Botanist Bassett Maguire of the New York Botanical Garden, probably because she was one of the collectors of the type collection of the species.

Conservation status: — The species is being classified as Critically Endangered ( CR, criterion B1 , subcriteria bi, iii, iv), as it has an area of occurrence of 82 km 2, forms populations with less than 30 adult individuals and has been collected in only five locations with frequent anthropic disturbance .

Morphological relationships and characterization: —Described by Irwin & Barneby (1978) as Cassia celiae , this species was included in the series Ch. sect. Absus subsect. Absus ser. Paniculatae for presenting large (2.4–5.7 × 1.4–5.7 cm), orbicular and divaricated leaflets, secondary and tertiary veins prominent on both surfaces, as well as flowers arranged in panicles with the adaxial petal similar to a stanrdard. Subsequently, Irwin & Barneby (1982) transferred it to the genus Chamaecrista since it had flowers the pedicels with two bracteoles, androecium actinomorphic with anthers of apical pores, in addition to elastically dehiscent fruits, making the following new combination Ch. celiae , which is maintained here.

Mendes et al. (2020) in a molecular phylogeny of Ch. ser. Paniculatae discussed the relationships between its species and presented Ch. celilae as a valid species. Cota et al. (2020) subordinate Ch. celiae as a synonym for Ch. orbiculata arguing that both species are tenuously differentiated and reported that Mendes et al. (2020) presented both species in a clade weakly support. However, verifying the work of Mendes et al. (2020) we found both species in a clade with maximum Posterior Probability (PP 1) conventional Bayesian Inference statistics presented by them, which is why we decided to keep both species as dictated, also associated with the discontinuous diagnostic morphology presented by both as below.

Although Ch. celiae is confused with Ch. orbiculata due to its arborescent habit, stem with conspicuously fissured bark, orbicular leaflets and very viscous inflorescence, they are distinguished by a set of characters that allows us to identify them as two distinct species such as leaves with only two pairs of blue-green leaflets with a smooth margin (vs. 2–4 pairs of light-green leaflets with a thickened margin in Ch. orbiculata ), pulvines with 1.5–2.2 mm long (vs. 1.2–6 mm), linear or subulate bracts (vs. lanceolate), as well as setose panicles (vs. setulose), viscous-verrucous buds (vs. villous, setulose or setose).