Byrsonima rupestris Francener & Mamede, 2017

Francener, Augusto, Almeida, Rafael Felipe De & Mamede, Maria Candida Henrique, 2017, Taxonomic novelties in Byrsonima (Malpighiaceae) from the state of Minas Gerais, Brazil, Phytotaxa 291 (2), pp. 133-140 : 134-139

1. Byrsonima rupestris Francener & Mamede , sp. nov. ( Fig. 1A–H )

Type: — BRAZIL. Minas Gerais: Parque Nacional da Serra da Canastra, Estrada para Sacramento, entrada Garagem de Pedras , 20 March 1995, fl., Nakajima et al. 922 (holotype: HUFU 8449 !; isotypes: SP 286157!, UESC 8609 !) .

Byrsonima rupestris differs from B. cipoensis Mamede (1980: 42) and B. variabilis Jussieu (1833: 78) by its unusual unbranched hairs covering the entire plant, and the leaf blades with all veins strongly prominent abaxially, even the tertiary ones.

Shrubs, 0.4–1.5 m tall, trunk erect, terete, velutinous, hairs 0.3–1.0 mm long, white or brown, unbranched or rarely branched with stalk up to 0.3 mm long; younger stems grayish white or ferruginous, older stems grayish, becoming glabrous. Stipules 6.0–7.3 × 1.8–4.0 mm, connate, triangular to ovate, abaxial surface velutinous, hairs 0.3–1.5 mm long, white, unbranched or rarely branched with stalk 0.5–0.8 mm long, adaxial surface shiny, glabrous or velutinous, hairs 0.5–1.5 mm long, brown, unbranched hairs present only at base. Leaves opposite, rarely verticillate; petiole 2.0– 10 mm long, velutinous, hairs 0.3–2 mm long, brown or whitish, unbranched or branched with stalk 0.1–0.2 mm long; leaf blades 3.2–15.5 × 2.1–7.0 cm, ovate, elliptic, obovate or lanceolate, base acute, subcordate or obtuse, margin entire, slightly revolute, sinuous, apex acute, acuminate or obtuse, adaxial side greenish, glaucous-green or light brown, velutinous to sparsely velutinous, hairs 0.2–1.4 mm long, whitish, unbranched or branched with, stalk up to 0.2 mm long, abaxial side usually ferruginous or white-ferruginous, densely velutinous to tomentose, hairs 0.5–1.4 mm long, whitish, unbranched, occurring mainly on the veins, rarely branched with stalk up to 0.3 mm long; venation brochidodromous, 5–12 pairs of secondary veins, adaxially bullate, abaxially strongly prominent, tertiary veins reticulate, adaxially impress, abaxially strongly prominent. Thyrses of 1-flowered cincinni, 5–43-flowered, flowers distributed in the median and distal part of the rachis; rachis 3.5–13.0 cm long, velutinous, hairs 0.4–1.5 mm long, whitish or brown, unbranched or branched with stalk up to 0.2–0.3 mm long; bracts and bracteoles at the base of pedicel, deciduous or not in fruit; bracts 4.5–7 × 0.8–1.5 mm, narrowly triangular, erect, adaxial side glabrous, abaxial side sericeous-velutinous, hairs 0.3–1.0 mm long, whitish or brown, unbranched or branched with stalk up to 0.1–0.4 mm long; peduncle sessile; bracteoles 3–4 × 0.8–1.0 mm, narrowly triangular, erect, adaxial side glabrous, abaxial side sericeous-velutinous, hairs 0.3–1.0 mm long, whitish or brown, unbranched or branched with stalk up to 0.1–0.4 mm long; pedicels 5.0– 12 mm long, velutinous, hairs 0.3–1.4 mm long, whitish or brown, unbranched or rarely branched with stalk up to 0.7 mm long. Sepals 3.5–4.0 × 2.2–2.5 mm, always bi-glandular, apex acute or rounded, erect, appressed to the androecium, adaxial side glabrous, abaxial side sericeous-velutinous, hairs 0.3–1.3 mm long, whitish or brown, unbranched; glands 1.5–2.3 × 1.0– 1.1 mm, white. Petals glabrous; lateral petals white, turning pink with age, limb cucullate, 4.5–6.0 × 5.0–6.0 mm, margin sinuate, claws 3.0–4.5 × 0.5–0.8 mm, reflexed, bent or twisted; posterior petal always yellow, limb patent, 3.0–5.0 × 4.0–5.0 mm, margin erose, claw 3.5–4.2 × 0.8–1.1 mm, erect. Stamens 10, connate at the base; filaments 2.4–3.1 × 0.4–0.9 mm, adaxially pilose at base, hairs unbranched, 1.5–3.0 mm long, brown, abaxially glabrous; connectives 1.5–2.2 × 0.5–0.7 mm, exceeding or not the locules (up to 1 mm long), glabrous; locules 2.2–2.7 × 0.5–0.7 mm, glabrous. Ovary conical, 1.5–2.0 × 1.7–1.8 mm, glabrous; ovules 0.8–1.0 × 0.4–0.5 mm; styles linear, 3.2–4.0 × 0.2–0.3 mm, subulate, bent at the apex, glabrous; stigma minute. Drupes 6–7 mm diam., ovoid or globose, glabrous; sepals expanded in fruit; pedicels bent or twisted.

Additional specimens examined (paratypes):— BRAZIL. Minas Gerais: Municipality of São Roque de Minas, Parque Nacional da Serra da Canastra, 19 November 2002, fl., Pacheco et al. 287 ( HUFU) ; loc. cit., Cachoeira Casca D’Anta, parte de cima, 23 August 1997, fl., Romero et al. 4503 ( CEPEC, HUFU) ; loc. cit., Chapadão do Diamante , 20 November 1995, fl., Romero et al. 3135A ( HUFU, SP016879 ) ; loc. cit., Chapadão do Diamante , 15 October 1997, fl., Nakajima et al. 2855 ( CEPEC, HUFU, UESC) ; loc. cit., entrada para o Retiro de Pedras , 27 September 1995, fl., Romero et al. 2869 ( HUFU, SP016882 ) ; loc. cit., estrada para a Cachoeira do Rolinhos , 26 September 1995, fl., Romero et al. 2855 ( HUFU, SP016869 ) ; loc. cit., estrada para Cachoeira Casca D’Anta, 28 September 1995, fl., Romero et al. 2960 ( CEPEC, HUFU, SP016881) ; loc. cit., estrada para Sacramento, 3 km da sede administrativa, 17 March 1995, fl., Romero et al. 1951 ( HUFU, SP016868 , UESC) ; loc. cit., estrada para Sacramento, 3 km da sede administrativa, 7 December 1994, fl., Nakajima et al. 665 ( HUFU, SP016876 ) ; loc. cit., estrada para Sacramento, 23 km da sede administrativa, 19 April 1994, fl., Nakajima et al. 300 ( HUFU, SP016878 ) ; loc. cit., estrada para Sacramento, entrada Garagem de Pedras , 16 October 1997, fl., Romero et al. 4658 ( HUFU, SP003449 ) ; loc. cit., Guarita de Sacramento , 18 November 1995, fl., Romero et al. 3109 ( HUFU, SP016880 ) ; loc. cit., Morro da Cachoeira da Casca D’Anta , 22 August 1994, fl., Romero et al. 1150 ( HUFU, SP016871 ) ; loc. cit., Morro próximo à sede administrativa, 15 October 1994, fl., Nakajima et al. 477 ( HUFU, SP016877 , UESC) ; loc. cit., Morro próximo à sede administrativa, 20 August 1994, fl., Romero 1116 ( HUFU) ; loc. cit., Paredão da parte de cima da Cachoeira da Casca D’Anta, 29 September 1995, fl., Nakajima et al. 1384 ( HUFU, SP016874 , UESC) ; loc. cit., paredão da parte de cima da Cachoeira da Casca D’Anta, 29 September 1995, fl., Nakajma et al. 1386 ( HUFU, SP016973 ) ; loc. cit., próximo ao córrego dos Passageiros, 19 July 1995, fl., Romero et al. 2624 ( HUFU) ; loc. cit., próximo à guarita de Sacramento, 14 October 1994, fl., Romero et al. 1190 ( HUFU, SP016870 , UESC) ; loc. cit., próximo à guarita de Sacramento, 6 December 1994, fl., Romero 1463 ( HUFU, SP016867 ) ; loc. cit., próximo ao Curral de Pedras , 18 October 1994, fl., Romero et al. 1313 ( HUFU, SP016866 ) ; loc. cit., trilha Casca D’Anta, 19 November 2002, fl. fr., Romero 6520 ( HUFU, SP003448 ) ; loc. cit., trilha da Cachoeira Casca D’Anta, 19 November 2002, fl. fr., Duarte et al. 52 ( CEPEC, HUFU) ; loc. cit., trilha para a parte de baixo da Cachoeira da Casca D’Anta, 29 September 1995, fl., Nakajima et al. 1390 ( HUFU, SP016872 , UESC) .

Distribution, habitat and phenology: — Byrsonima rupestris is endemic to Serra da Canastra surroundings, southwest of Minas Gerais state ( Fig. 2 ), occurring in areas of neotropical savannas and rocky fields (cerrados and campo rupestres). Flowering occurs from August to April, and fruiting in November.

Conservation status: — Byrsonima rupestris is mostly distributed throughout Serra da Canastra National Park, a conservation unit located within the Cerrado domain with high rates of annual fires. Due to its extension of occurrence of 1,468.545 km 2, and area of occupancy of less than 12.000 km ² it should be regarded as Endangered [criteria B1ab(iii)+2ab(iii)].

Etymology: —The epithet makes reference to its restricted distribution on rocky fields (campos rupestres).

Taxonomic notes: — Byrsonima rupestris is easily recognized by its unusual unbranched hairs covering the entire plant ( Fig. 3 ), especially on the abaxial side of leaf blades, and by the strongly prominent veins on the abaxial side of leaf blades. In Malpighiaceae as a whole the hairs are usually unicellular and medifixed, consisting of a stalk bearing two arms (branched). Sometimes one of the arms is reduced to a rudimentary short spur (or is entirely suppressed), with the hair then appearing basifixed (unbranched). This type of hair is very unusual within the genus, being only previously found on the leaves of B. verbascifolia (Linnaeus, 1753: 426) De Candolle (1824: 579) . Byrsonima rupestris is very similar to Byrsonima cipoensis Mamede (1980: 42) , Byrsonima stannardii Anderson (1992: 725) and Byrsonima variabilis Jussieu (1833: 78) . These species are restricted to rocky fields (campos rupestres) over Espinhaço Range, and share the presence of four white lateral petals, and a yellow posterior petal (except in Byrsonima stannardii , in which all petals are yellow). These species can be easily distinguished by the following characters:

1. Shrubs or trees; all petals yellow, turning orange or red with age; anthers sericeous between locules .......................... B. stannardii 1. Subshrubs or shrubs; only posterior petal yellow (lateral petals white), turning pink with age; anthers glabrous............................2 2. Abaxial side of leaf blades mostly covered with unbranched hairs; primary, secondary, and tertiary veins strongly prominent........

........................................................................................................................................................................................... B. rupestris 2. Abaxial side of leaf blades covered with branched hairs; primary, and secondary veins prominent, but usually hidden by indumenta, tertiary veins plane to prominulous........................................................................................................................................3 3. Shrubs (0.6–)1.0–2.0(–3.5) m tall; leaves 3.0–15.5 × 2.0–7.0 cm, abaxially densely tomentose or glabrescent ............ B. variabilis 3. Subshrubs 0.3–0.7 m tall; leaves 1.5–7.0 × 0.4–2.0 cm, abaxially sparsely tomentose................................................... B. cipoensis

2. Byrsonima minarum Francener & Mamede , nom. et stat. nov. ( Fig. 1I–K ) ≡ Byrsonima pachyphylla var. latifolia Niedenzu (1901: 27) , non Byrsonima latifolia (Jussieu, 1833: 76) Kralik (1908: 284) . Lectotype (designated here): — BRAZIL. Minas Gerais: Serra do Caraça, 1 March 1892, fl. fr., Ule 2456 (lectotype: RB146817!; isolectotype: R194 17!).

Trees, trunk striate, erect, terete, glabrous; stem sericeous, hairs 0.3–1.0 mm long, brown, sessile or stalk up to 0.2 mm long. Stipules 5.5–7.5 × 3.8–4.0 mm, connate, triangular to ovate, adaxial side shiny, glabrous to glabrescent at base, hairs 0.3–0.6 mm long, brown, sessile, abaxial side sericeous, hairs 0.3–1.0 mm long, brown, sessile. Leaves opposite, entire; petioles 8.0– 12 mm long, cylindrical, sericeous, hairs 0.2–1.0 mm long, brown, sessile to stalk up to 0.2 mm long; leaf blades 9.5–14.2 × 4.2–6.6 cm, elliptic or obovate, base acute, margin entire, slightly revolute, sinuous, apex acute, adaxial side dark green, sparsely sericeous, hairs 0.3–0.7 mm long, whitish, sessile, abaxial side ferruginous, sparsely sericeous, hairs 0.3–1.0 mm long, light brown, sessile to stalk up to 0.2 mm long; venation brochidodromous, 9–12 pairs of secondary veins, adaxially impressed, abaxially prominent; tertiary veins reticulate, prominent. Thyrses of 1-flowered cincinni, with 6–20 flowers distributed in the median to distal part of the rachis; rachis 8.5–13.0 cm long, tomentose-sericeous, hairs 0.2–1.0 mm long, brown, sessile to stalk up to 0.2 mm long; bracts not seen; peduncle sessile to up to 1.0 mm long; bracteoles ca. 2.0 × 1.5 mm, triangular, adaxial side glabrous, abaxial side sericeous, hairs 0.2–0.7 mm long, light brown, sessile to stalk up to 0.1 mm long; pedicels 14–16 mm long, tomentose-sericeous, hairs 0.3–0.7 mm long, light brown to brown, sessile to stalk up to 0.2 mm long. Sepals 3.7–4.0 × ca. 2.0 mm, always bi-glandular, appressed to the androecium, apex rounded, revolute, adaxial side glabrous, abaxial side sericeous, hairs 0.3–0.7 mm long, whitish to light brow, sessile to stalk up to 0.1 mm long; glands 2–2.8 × 1.2–1.4 mm, yellow. Petals yellow, glabrous; lateral petals reflexed, limb cucullate, 5–6 × 5–6.5 mm, margin sinuate, claw 2.5–3 × 0.5–0.6 mm, twisted; posterior petal with limb patent, ca. 4.0 × 5.0 mm, margin erose, claw ca. 4.2 × 1.0 mm, erect. Stamens 10, connate at base; filaments 2.0–2.2 × 0.5–0.9 mm, adaxially pilose at base, hairs simple, 0.9–2.5 mm long, light brown, abaxially glabrous; connective 1.5–1.8 × 0.5–0.7 mm, not exceeding the locules, glabrous; locules 2.0–2.1 × 0.5–0.6 mm, apex rounded, glabrous. Ovary conical, ca. 1.8 × 1.8 mm, sericeous, hairs 0.5–1.1 mm long, shiny, light brown, sessile to stalk up to 0.1 mm long; ovules 0.7–0.9 × ca. 0.5 mm; style linear, 3.6–3.6 × 0.3–0.4 mm, erect, subulate, bent at the apex, glabrous; stigma minute. Drupes (immature) 6.1–7.6 mm diam., globose, sparsely sericeous; sepals not expanded in fruit; pedicels straight, reflexed.

Additional specimens examined: — BRAZIL. Minas Gerais: Municipality of Ouro Preto , 18 December 1837, fl., Luschnath s.n. (BR0857848) ; loc. cit., campo de São Sebastião, 1883, fl., Glaziou 14558 (K001221647) ; Municipality of Tiradentes, Vila de São José , s.d., fl., Pohl s.n. (BR0857983) .

Distribution, habitat and phenology: — Byrsonima minarum is known from Serra do Caraça and Serra de Tiradentes in the state of Minas Gerais, Brazil ( Fig. 4 ), occurring in neotropical savannas (cerrado), or in rocky fields (campo rupestre). Flowering occurs from December to March, and fruiting in March.

Conservation status: —The type locality of Byrsonima minarum has been recently damaged by the collapsing of a mine-tailing dam, which destroyed part of the natural vegetation from Serra do Caraça (Garcia et al. in press). Due to the continuous decline of habitat quality, an extent of occurrence of 1,093.459 km ², and area of occupancy of less than 12.000 km ², this species should be regarded as Endangered [B1ab(iii)].

Etymology: —The epithet makes reference to the restricted distribution of B. minarum in the state of Minas Gerais.

Nomenclatural notes: — Niedenzu (1901) cited seven collections (and potentially eight specimens) when describing Byrsonima pachyphylla var. latifolia : Luschnath s.n. (BR0857848!), Pohl s.n. (BR0857983!), Glaziou 14558 (K001221647!), Schwacke 9347 (not found), Schwacke 11408 (RB00578226!), Ule 2454 (not found), and Ule 2456 (RB146817!, R19417!). From these syntypes, Schwacke 11408 revealed to be a specimen of the fern Serpocaulon laetum ( Presl 1836: 188) Schwartsburd & Smith (2013: 91) ; the specimens Schwacke 9347 and Ule 2454 were not found; and from the remaining specimens, we have chosen Ule 2456 as the lectotype due to being the single collection with a duplicate, and stored in Brazilian herbaria.

Taxonomic notes: — Byrsonima minarum is a small tree with yellow petals, prominent secondary veins in the abaxial surface of leaf blades, connectives not exceeding the locules, and anthers glabrous. At first sight, it seems very similar to B. macrophylla (Persoon 1805: 506) Anderson (1993: 362) , a common species in rocky fields from the state of Minas Gerais, which also bears prominent secondary veins. However, B. macrophylla bears pink petals, with only the posterior petal showing a yellow claw (vs. petals with yellow limbs and claws in B. minarum ), and connectives exceeding the locules in almost all anthers (vs. connective not exceeding the locules in B. minarum ).

Figures

FIGURE 1. Byrsonima rupestris A–H: A. Habit, B.Abaxial side of leaf blades, C. Node with bases of leaves and stipules, D. Hairs on the abaxial side of leaf blades, E. Lateral view of the flower with the bract and one bracteole, F. Gynoecium with glabrous ovary, G. Stamens, adaxial and lateral view, H. Drupe. Byrsonima minarum I-K: I. Habit, J. Stamens, adaxial and lateral view, K. Lateral view of an immature fruit (A–H, Nakajima et al. 300, I–K, Ule 2456).

FIGURE 2. Distribution of Byrsonima rupestris and similar species: Green circles—B. rupestris; Red circles—B. variabilis; Yellow circles—B. cipoensis; Blue circles—B. stannardii.

FIGURE 3. Hairs from Byrsonima rupestris: Branched hairs marked with asterisk, and unbranched hairs marked with arrows.

FIGURE 4. Distribution of Byrsonima minarum.