Mezilaurus conceicionensis L. C. S. Assis, P. B. Meyer & F. M. Alves 2022, sp. nov.

Mezilaurus conceicionensis L.C.S.Assis, P.B.Meyer & F.M.Alves, sp. nov. (Figs 1–2).

Type:— BRAZIL. Minas Gerais: Conceição do Mato Dentro, Fazenda Santa Cruz, Propriedade da Vale, 1025 m, 19°03’25”S, 43°24’11”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. de Paula 3803 (holotype, BHCB 203295!; isotype, RB!).

Diagnosis:— Mezilaurus conceicionensis is similar in floral structure to Mezilaurus revolutifolia, however, it differs by having a shrubby habit, the branches distally puberulous, stamens connate and globoid fruits.

Shrubs to small trees, 1.5–5 m tall. Branches with rhythmic growth; branchlets cylindrical, grayish to dark-brown, distally puberulous to glabrescent, with scars of senescent leaves and conspicuous lenticels. Apical buds totally covered by sericeous and translucent light-brown hairs. Leaves alternate to sub-opposite, clustered at the apex of the branchlets; petioles 0.6–1.8 cm long, 15–20% of the leaf length, plane to prominent at the adaxial surface, glabrous to subglabrous; blades 1.8–10 cm × 0.9–4.2 cm, obovate to oblanceolate, base attenuate, margins revolute, apex emarginate, rounded, obtuse or rarely mucronate, adaxial and abaxial surfaces glabrous to glabrescent, primary, secondary, and tertiary veins prominent at both surfaces, secondary veins brochidodromous, diverging at 35–75° to the primary vein, domatia absent. Cataphylls present, totally covered by sericeous and translucent light-brown hairs. Inflorescences 3.5– 6 cm long, dibotrya, lateral branchlets umbeliform, raquis cerose, partially covered by tomentose indument and lightcream hairs. Flowers 3–6 mm long, globose to sub-globose; pedicels 2.5–4.5 mm long, glabrous; hypanthium ca. 1 × 1.5 mm, cotiliform, inner and outer surfaces glabrous; tepals 0.2–0.6 × 0.5–1 mm, shorter than the hypanthium, ca. 1 / 3 of the flower length, subequal, outer tepals slightly shorter and wider than the inner ones, outer tepals depressed-ovate, glabrous to glabrescent, inner tepals broadly ovate to depressed-ovate, glabrous to glabrescent; stamens 1–1.1 mm long, connate, inserted at anthesis, filaments 0.5–0.6 mm long, rectangular, partially to totally covered by tomentose and opaque indument, anthers slightly deltate, glabrous, rarely papillose, locelli apical; pistil ca. 1.2 × 1.0 mm, ovary ca. 0.8 mm long, narrowly ellipsoid, glabrous. Style ca. 0.4 mm long, ca. 1 / 3 of the pistil length, glabrous. Fruits 1.8–3 cm, globose to subglobose, glaucous. Cupules ca. 1 × 4 mm, plane.

Paratypes:— BRAZIL. Minas Gerais: Conceição do Mato Dentro, 1043 m, 19º02’47”S, 43º23’19”W, 16 February 2016 (fl.), E. Tameirão-Neto & C.V. Vidal 5431 (BHCB!, RB!); 19º00’03”S, 43º24’05”W, 14 August 2016 (fl., fr.), E. Tameirão-Neto & C.V. Vidal 5112 (BHCB!, RB!); 1005 m, 19º33’99”S, 43º23’13”W, 24 July 2014 (fl.), C.V. Vidal 1258 (BHCB!, RB!); 1010 m, 19º34’98”S, 43º23’70”W, 11 December 2014 (fl.), C.V. Vidal 1321 (BHCB!, RB!); Fazenda Santa Cruz, Propriedade da Vale, 1010 m, 19°03’04”S, 43°23’12”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3775 (BHCB!); 1014 m, 19°03’03”S, 43°23’12”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3776 (BHCB!); 1015 m, 19°03’03”S, 43°23’13”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3777 (BHCB!); 1018 m, 19°03’03”S, 43°23’13”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3778 (BHCB!); 1018 m, 19°03’03”S, 43°23’13”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3779 (BHCB!); 1006 m, 19°03’04”S, 43°23’11”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3780 (BHCB!); 1003 m, 19°03’04”S, 43°23’11”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3781 (BHCB!); 1001 m, 19°03’05”S, 43°23’11”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3782 (BHCB!); 993 m, 19°03’05”S, 43°23’10”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3783 (BHCB!); 983 m, 19°03’05”S, 43°23’07”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3784 (BHCB!); 1014 m, 19°03’03”S, 43°23’11”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3785 (BHCB!); 1015 m, 19°03’03”S, 43°23’12”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3786 (BHCB!); 1014 m, 19°03’03”S, 43°23’12”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3787 (BHCB!); 1015 m, 19°03’03”S, 43°23’13”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3788 (BHCB!); 1016 m, 19°03’03”S, 43°23’13”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3789 (BHCB!); 1042 m, 19°03’20”S, 43°23’16”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3790 (BHCB!); 1041 m, 19°03’03”S, 43°24’17”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3791 (BHCB!); 1044 m, 19°03’21”S, 43°24’16”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3792 (BHCB!); 1045 m, 19°03’21”S, 43°24’16”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3793 (BHCB!); 1046 m, 19°03’21”S, 43°24’16”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3794 (BHCB!); 1036 m, 19°03’22”S, 43°24’15”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3795 (BHCB!); 1033 m, 19°03’23”S, 43°24’15”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3796 (BHCB!); 1034 m, 19°03’23”S, 43°24’14”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3797 (BHCB!); 1035 m, 19°03’24”S, 43°24’13”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3798 (BHCB!); 1036 m, 19°03’24”S, 43°24’13”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3799 (BHCB!); 1030 m, 19°03’24”S, 43°24’12”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3800 (BHCB!); 1026 m, 19°03’25”S, 43°24’12”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3801 (BHCB!); 1024 m, 19°03’25”S, 43°24’11”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3802 (BHCB!); 1027 m, 19°03’25”S, 43°24’11”W, 20 February 2019 (fl., fr.), P.B. Meyer & N.L. Paula 3804 (BHCB!). 19º30’11”S, 43º23’04”W, 16 August 2012 (fl., fr.), E. Tameirão-Neto & C.V. Vidal 5156 (BHCB!, RB); Ibid., 1007 m, 19º05’13”S, 43º38’69”W, 30 July 2017 (fl.), P.B. Meyer 3062 (BHCB!, CGMS!, K!, MO!, RB!); Ibid., Serra da Ferrugem, 19º00’03”S, 43º23’51”W, 27 July 2017 (fl., fr.), A.S. Quaresma & C.T. Oliveira 854 (BHCB!, HEPH!, RB!).

Distribution and ecology:— Mezilaurus conceicionensis is endemic to the campos rupestres over canga couraçada in the municipality of Conceição do Mato Dentro, State of Minas Gerais, Brazil (Fig. 5a of Assunção-Silva & Assis [2021] as Mezilaurus sp. nov 1), between 980–1050 m, associated to genus Vellozia Vandelli (1788: 32), a typical genus of campos rupestres (Fig 1).

Phenology: — During fieldwork, the flowering of M. conceicionensis was continuously observed from August 2018 to July 2019, without interruptions, with peaks being recorded in the months of October 2018 and March 2019. Fruiting was also observed throughout this period, with peaks mostly from greater amounts of fruit being recorded between the months of May and July 2019.

Etymology: — The epithet pays tribute to the type locality, the municipality of Conceição do Mato Dentro, MG, Brazil, located at the base of Serra da Ferrugem.

Conservation status:— Mezilaurus conceicionensis is restricted to the Serra da Ferrugem mountain range (also called “Serra da Serpentina”), municipality of Conceição do Mato Dentro, State of Minas Gerais, Brazil. So far, it is known only from five subpopulations in this mountain range. According to the IUCN (IUCN 2012, 2016), this species can be tentatively be classified as Critically Endangered - CR (A4c;B1ab(iii) + 2ab(iii)). This classification is based on its small AOO, estimated in 0.49 km ², small EOO, calculate in 21.927 km ², and a continuing and probably not reversible reduction in its population size, based on the decline of this AOO, EOO and habitat quality.

Mezilaurus conceicionensis is distinct from the remaining species of the genus by its shrubby habit, leaves with both surfaces glabrous to glabrescent, flowers clustered (umbel-like) along the lateral branches of the inflorescences, flowers globose, glabrous to glabrescent, tepals ca. 1 / 3 the flower length, shorter than the hypanthium, stamens connate and inserted, and globoid fruits.

Mezilaurus conceicionensis can be confused with the collections of M. revolutifolia F.M.Alves & P.L.R.Moraes in Alves et al. (2011: 506), but the latter is characterized by its tepals as long as the hypanthium, ca. 1 / 2 the flower length to slightly larger, exserted and free stamens, and ellipsoid to obovoid fruits. Mezilaurus conceicionensis can also be confused with M. crassiramea (Meissner 1864: 117) Taubert ex Mez (1892: 112), also found in campos rupestres from the State of Minas Gerais. However, in M. crassiramea, the leaves are abaxially hirsute, villous or lanate, petioles are 1–10% of the leaf length, lanate to puberulous, the lateral branch of the inflorescences is racemiform, the stamens are exserted and free, and the fruits are ca. 3.1 × 2.8 cm, ellipsoid to obovoid. A key to the species of Mezilaurus from Southeastern Brazil is presented below.