Pleroma canastrense R. Romero, R. Pereira & P. J. F. Guim., 2024

Romero, Rosana, Pereira Silva, Rodrigo & Guimarães, Paulo José Fernandes, 2024, Two new Pleroma species and an updated key: Melastomateae from the Serra da Canastra National Park, Minas Gerais, Brazil, PhytoKeys 247, pp. 11-27 : 11-27

Pleroma canastrense R. Romero, R. Pereira & P. J. F. Guim. sp. nov.

Figs 1 , 2 , 3

Type.

Brazil • Minas Gerais. Parque Nacional da Serra da Canastra. São Roque de Minas: campo rupestre do morro próximo à sede administrativa do parque ; 26 June 1994; fl. fr., R. Romero & J. N. Nakajima 1039 (holotype HUFU!; isotypes: BHCB!, RB!, UEC!) .

Diagnosis.

The coriaceous leaf blade, broadly ovate to orbicular, entire and adpressed-margin, with 11–17 basal acrodromous veins, the stamens with a short pedoconnective and an inconspicuous ventral appendage together with the white petals, distinguish this species from another Pleroma .

Description.

Subshrubs or shrubs, 0.6–1.8 m tall, decumbent. Stem terete to subterete, glabrous, or with setose trichomes in the basal portion. Younger branches quadrangular, flattened at the apex, with spherical glands, or glabrous, older branches terete, glabrous, internodes 2–5 cm long. Leaves sessile, decussate, horizontal, isomorphic in size at each node; blade 2.5–6.5 × 2–5 cm, discolorous (when fresh and dry), coriaceous, adaxial surface darker, broadly ovate to orbicular, obtuse to acute at the apex, rarely rounded, with a terminal trichome, 0.5–1 mm long, base cordate, semiamplexicaul, margin entire, adpressed-strigose, marginal trichomes 2–4 mm long, both surfaces glabrous, acrodromous veins 11–17, basal, principal vein lighter, conspicuously visible on both surfaces and secondary veins tenuous on the abaxial surface. Panicles of simple or compound dichasium, reduced or not, terminal; bracts two, 5–12.5 × 3–8.5 mm, caducous, leafy, sessile, coriaceous, largely ovate to orbicular, elliptic-lanceolate, obtuse to acute at the apex, base truncate, semiamplexicaul, margin strigose-ciliate, trichomes 0.3–1 mm long, both surfaces glabrous; bracteoles two, 3–7.5 × 2–6.7 mm, caducous, brownish, cucullate, membranaceous, both surfaces covered with spherical glands, margin glandular-ciliate, mainly at the apical portion. Flowers 5 - merous; pedicel 1–2.5 mm long, glabrous; hypanthium 3–7 × 3–6 mm, green or glaucous, cylindrical, glabrous, furfuraceous; calyx tube 0.3 mm long; sepals 2–4 × 1.5–3 mm, green or glaucous, scarious, oblong, rounded at the apex, margin glandular-ciliate, furfuraceous; petals 8–14 × 9–12 mm, white, largely ovate, rounded or slightly retuse at the apex, base attenuate, margin entire, inconspicuously glandular-ciliate; androecium subisomorphic, stamens 10; filaments 4–7 mm long, white, filiform, glabrous or with sparse glandular trichomes in the basal portion; anthers 3–5 mm long, cream, oblong, straight, pore inclined ventrally, pedoconnective ca. 0.2 mm long, ventral appendage ca. 0.1 mm long, slightly bilobed, dorsal appendage ca. 0.1 mm long, lobed, glabrous; ovary 5 - locular, half-inferior, free apical portion densely sericeous; style ca. 9 mm long, cream, filiform, slightly curved at the apex, glabrous, stigma truncate. Fruits loculicidal, capsules coated by persistent cupuliform hypanthium, 6–8.3 × 5–6.8 mm, brownish, oblong. Seeds ca. 0.5 × 0.3 mm, brown, numerous, cochleate, testa papillose.

Distribution and habitat.

So far, we know Pleroma canastrense only from the Serra da Canastra National Park, where it is probably endemic (Fig. 3 ). The beautiful populations with white flowers occur exclusively in campo rupestre.

Conservation status.

Pleroma canastrense has an area of occupancy (AOO) of 48 km 2. Although this species has a distribution restricted to Serra da Canastra, we indicate it preliminarily here as “ Least Concern ” (LC), according to the IUCN categories ( 2012, 2022). This assessment is because most individuals are in a conservation unit with complete federal protection, established almost 50 years ago, with no significant threats to the populations. Furthermore, we have not identified a continued decline in occupancy over the past 30 years (R. Romero, pers. obs.).

Phenology.

Pleroma canastrense was collected in flower from April to August and in fruit from June to October.

Etymology.

The specific epithet refers to the restricted occurrence of this species in the campo rupestre of Serra da Canastra, Minas Gerais state, Brazil. The name “ Serra da Canastra ” is due to the similarity presented by the immense plateau, which, when viewed from afar, resembles a canastra, a term of Greek origin used to name a type of rustic chest with a rectangular shape.

Discussion.

Pleroma canastrense resembles P. wurdackianum (R. Romero & A. B. Martins) P. J. F. Guim. & Michelang. , which also occurs in the Serra da Canastra National Park ( Romero and Martins 2003). Both species share a subshrubby or shrubby habit, terete to subterete stem, glabrous and sometimes with setose trichomes on the basal portion, sessile leaves, discolorous leaf blade, cordate at the base, semiamplexicaul, and entire and adpressed-strigose margin with spiny trichomes. However, P. wurdackianum has pink petals (vs. white in P. canastrense ), hypanthium and leaf blade with spherical glands (vs. glabrous). Pleroma canastrense is also similar to P. integerrimum (R. Romero & A. B. Martins) P. J. F. Guim. & Michelang. , known only from Serra Preta in Delfinópolis ( Romero and Martins 2003), since both have flowers with white petals. However, P. integerrimum differs in having a chartaceous and concolorous leaf blade (vs. coriaceous and discolorous in P. canastrense ), glabrous at the margin (vs. adpressed-strigose).

Thirty years ago, John Julius Wurdack (1921–1998) wrote the following note on the sheet Romero & Nakajima 1039 from HUFU herbarium: “ Svitramia sp. aff. S. hatschbachii Wurdack (currently as Pleroma gertii P. J. F. Guim. & Michelang. ), but leaf cilia shorter, blade relatively broader and scarcely puncticulate, calyx lobes shorter, corolla white and larger, anthers longer. ” Pleroma canastrense resembles P. gertii , the latter occurring preferentially in campo rupestre and more rarely in campo limpo and sujo in the south and southwest of Minas Gerais, i. e., a distribution that exceeds the limits of the Serra da Canastra National Park. However, P. gertii has elliptic, elliptic-lanceolate, or ovate to ovate-lanceolate leaf blade (vs. broadly ovate to orbicular in P. canastrense ) with 7–9 basal acrodromous veins (vs. 11–17), and purple petals (vs. white).

The specimen G. J. Shepherd et al. 7032 ( UEC 055432) deposited at UEC was first named as Svitramia alba by Angela Borges Martins (1945 –) & João Semir (1937–2018) and this sheet annotated as holotype, but this name was never published by them.

Additional specimens examined (paratypes).

Brazil • Minas Gerais. Parque Nacional da Serra da Canastra. Capitólio: Reserva de Furnas ; 20 February 1978; (fl), G. J. Shepherd et al. 7032 ( UEC 055432 - online image!) • Morro do Chapéu ; 24 July 1993 (fl, fr); R. Simão-Bianchini & S. Bianchini 413 ( HUFU!, SP!) • Paraíso perdido, córrego Quebra-Anzol ; 29 September 2005 (fr); J. N. Nakajima 3737 ( HUEFS!, HUFU!, VIC!) • estrada de Capitólio para Passos ; 1 October 2005 (fl, fr); R. Romero 7264 ( HUFU!) • estrada para Pedreira Souza ; 7 November 2005 (fl); J. N. Nakajima et al. 4053 ( HUFU!) • estrada atrás do Paraíso Perdido ; 12 July 2006 (fr); R. Romero et al. 7794 ( HUFU!, RB!, SPF!, OUPR!, UEC!) • estrada para pedreira ; 21 March 2007 (fr); P. H. N. Bernardes et al. 45 ( HUFU!, OUPR!, VIC!) • morro atrás da pousada do Rio Turvo ; 21 May 2007 (fl, fr); P. H. N. Bernardes et al. 140 ( HUFU!, P!, UB!) • estrada para Cachoeira Feixo da Serra ; 13 July 2007 (fl, fr); R. Romero et al. 7795 ( HUFU!, NY!, SPF!, RB!, UB!, UEC!, UFG!) • Chapadão de Furnas ; 18 May 2013 (fr); M. J. R. Rocha 985 ( HUFU!, BHCB!) • Delfinópolis: estrada para a Babilônia ; 24 May 1996 (fl, fr); R. Romero & J. N. Nakajima 3438 ( HUFU!) • Cachoeirinhas ; 27 February 2000 (fr); A. C. B. Silva 302 ( HUFU!, SPF!, R!) • 2 May 2001 (fl, fr); A. C. B. Silva 881 ( HUFU!, SPF!, R!) • s. d. (fl, fr); A. C. B. Silva 422 ( HUFU!, SPF!, R!) • trilha Casinha Branca ; 11 April 2002 (fl); R. A. Pacheco et al. 101 ( HUFU!) • trilha do Zé Carlinho, subida para a Serra do Cemitério ; 9 October 2002 (fr); J. N. Nakajima et al. 3193 ( HUFU!, OUPR!, VIC!) • Paraíso Selvagem ; 11 March 2003 (fl); R. Romero et al. 6707 ( HUFU!) • trilha do S. Cannyon ; 16 May 2003 (fl, fr); R. Romero et al. 6921 ( HUFU!, UB!, UEC!) • estrada para Pedreira Souza ; 30 September 2005; J. N. Nakajima et al. 3946 ( HUFU!, K!, OUPR!, P!) • estrada para Pedreira Souza ; 17 February 2006; R. Romero et al. 7704 ( CESJ!, HUFU!, UFG!) • trilha Cachoeira Águas Claras ; 23 June 2010 (fl); P. O. Rosa et al. 1306 ( HUFU!, K!, P!, VIC!) • São Roque de Minas: Parque Nacional da Serra da Canastra ; 20 August 1994 (fl, fr); R. Romero & J. N. Nakajima 1118 ( HUFU!, SPF!, UFG!) • 15 October 1994 (fr); J. N. Nakajima et al. 452 ( HUFU!, OUPR!, UB!) • estrada São Roque de Minas para Sacramento ; 16 October 1994 (fr); R. Romero & J. N. Nakajima 1268 ( HUFU!, VIC!) • Cachoeira Casca D’Anta ; 17 October 1994 (fr); J. N. Nakajima & R. Romero 554 ( HUFU!, UEC!) • córrego dos Passageiros ; 11 May 1995 (fl); R. Romero et al. 2206 ( CESJ!, HUFU!, NY!, OUPR!) • estrada para Cachoeira Casca D’Anta ; 12 May 1995 (fl); J. N. Nakajima et al. 1026 ( HUEFS!, HUFU!, K!, P!, RB!, SPF!, UEC!, VIC!) • Parque Nacional da Serra da Canastra ; 15 July 1995 (fl, fr); R. Romero et al. 2384 (HUEFS!, HUFU!, OUPR!, RB!, SPF!, UEC!) • Cachoeira da Casca D’Anta ; 17 July 1995 (fl, fr); R. Romero et al. 2505 ( CESJ!, HUFU!, NY!, OUPR!) • caminho para a Cachoeira Casca D’Anta ; 18 July 1995 (fl, fr); J. N. Nakajima et al. 1258 ( HUEFS!, HUFU!, RB!, VIC!) • paredão da Cachoeira dos Rolinhos ; 26 May 1996 (fl); J. N. Nakajima & R. Romero 1775 ( HUFU!, P!, UB!, UFG!) • Chapadão do Diamante ; 9 July 1996 (fl); J. N. Nakajima et al. 1929 ( HUFU!, UEC!) • estrada para Cachoeira Casca D’Anta ; 10 July 1996 (fl); J. N. Nakajima et al. 1939 ( HUFU!, UB!, UFG!) • 10 July 1996 (fl, fr); J. N. Nakajima et al. 1947 ( HUEFS!, HUFU!, K!, P!, US) • córrego dos Passageiros ; 11 July 1996 (fl, fr); J. N. Nakajima et al. 2011 ( CESJ!, HUFU!, K!, NY!, US) • próximo à sede administrativa ; 11 July 1996 (fl, fr); J. N. Nakajima et al. 2043 ( HUFU!, RB!, UEC!, VIC!) • Cachoeira Casca D’Anta ; 10 August 1996 (fl); J. N. Nakajima et al. 1948 ( CESJ!, HUEFS!, HUFU!, OUPR!) • trilha do paredão da Serra da Canastra ; 17 April 1997 (fl); R. Romero et al. 4142 ( HUFU!, SPF!, US!) • estrada para Fazenda do Fundão ; 25 June 1997 (fl, fr); R. Romero et al. 4265 ( HUFU!, NY!, OUPR!, UEC!) • Cachoeira dos Rolinhos ; 29 June 1997 (fl, fr); R. Romero et al. 4369 ( CESJ!, HUFU!, OUPR!) • Chapadão do Diamante ; 29 June 1997 (fl); R. Romero et al. 4330 ( HUFU!, UB!, UFG!) (fl, fr), R. Romero et al. 4336 ( CESJ!, HUFU!, UFG!) • estrada para o sítio João Domingos ; 20 August 1997 (fl); J. N. Nakajima et al. 2635 ( CESJ!, HUFU!, UB!, UFG!) • estrada para o Vale dos Cândidos ; 22 August 1997 (fr); J. N. Nakajima et al. 2708 ( HUFU!, NY!, US!) (fr), J. N. Nakajima et al. 2696 ( HUFU!, RB!, UB!, VIC!) • Guarita de São Roque de Minas ; 23 June 2001 (fl); R. Romero et al. 6140 ( CESJ!, HUFU!, UFG!) • parte alta da Cachoeira Casca D’Anta ; 14 May 2007 (fl); A. P. M. Santos & J. F. Silva 403 ( HUEFS!, HUFU!) • morro próximo à sede administrativa ; 23 July 2009; (fl), P. J. F. Guimarães et al. 402 ( RB!) • alto da Casca D’Anta ; 29 May 2014 (fl); A. F. A. Versiane et al. 647 ( HUFU!, NY!) .

Figures

Figure 1. Pleroma canastrense R. Romero, R. Pereira & P. J. F. Guim.: A flowering branch B adaxial leaf surface C detail of the leaf blade margin D flower E hypanthium and sepals F detail of the hypanthium surface G petal, abaxial view H petal margin detail I stamens, in lateral view J gynoecium K stigma detail L cross section of the ovary M fruit N seed (Illustration by Klei Souza based on the holotype (R. Romero & J. N. Nakajima 1039).

Figure 2. Pleroma canastrense R. Romero, R. Pereira & P. J. F. Guim. A rocky outcrop at Serra da Canastra National Park, Minas Gerais, Brazil, the type locality of Pleroma canastrense B subshrub in campo rupestre near the road C flowering specimen showing the beautiful leaf architecture D flower E fruiting branch. Photos: Rosana Romero.

Figure 3. Geographical distribution of Pleroma canastrense and Pleroma viscosa in the Serra da Canastra National Park, Minas Gerais, Brazil [Adapted from Alves (2022)]. White line refers to the area of Serra da Canastra National Park.