Myrcia subavenia

Santos, Matheus F., Lucas, Eve & Sano, Paulo T., 2018, A taxonomic monograph of Myrcia sect. Sympodiomyrcia (Myrteae, Myrtaceae), Phytotaxa 380 (1), pp. 448-450 : 448-450

16. Myrcia subavenia (O. Berg 1857 –1859: 69) N. Silveira (1985a: 66) ( Figures 3H , 10 , 43 and 44 )

≡ Aulomyrcia subavenia O.Berg. Type :— BRAZIL. No date (fl.), Sellow s.n. (lectotype LE! designated by Sobral et al. 2010, isolectotype K [barcode K000344403]!)

= Aulomyrcia ferruginea O. Berg (1857 –1859: 552). Myrcia lapensis N. Silveira (1985a: 67) .Type:— BRAZIL. Minas Gerais: “ad ripas rivul. S. da Lapa”, November 1824 (fl.), Riedel 972 (lectotype LE [barcode LE00007061]! designated by Santos et al. (2016b)). Remaining syntypes:— BRAZIL. Minas Gerais: “ad rivulor. S. da Lapa”, November 1824 (fl.), Riedel 972 (LE [barcode LE00007062]!, P [barcode P00161263]!)

Subshrub, shrub to tree 0.5–7.0 m high. Epidermal peeling present in immature parts; trichomes ferruginous, brown, light brown to white, 0.1–0.6 mm long. Twig when immature brownish or straw-like (when dry), flattened, sometimes sulcate, slightly keeled, tomentose, minutely tomentose, pubescent or puberulent; mature twig greyish (when dry), cylindrical, cortex slightly cracked, glabrescent to glabrous; branching sympodial (sometimes monopodial), 2–4 branches per node, epidermal protrusion present at the nodes, internode 0.8–7.0 cm long; cataphyll scale-like to foliaceous, 2–10 × 1–2 mm, present in all internodes (rarely only at the basal one of a new branch), early deciduous, free, lanceolate or ovate, externally tomentose or pubescent, internally with scattered trichomes to glabrous; terminal node with central bud developed, tomentose or pubescent, lateral ones undeveloped. Leaf discolorous, coriaceous, blade 1.1–8.2 × 0.4–1.8 cm, narrowly elliptic, widely elliptic or oblanceolate to very widely obovate, apex caudate, acuminate to rounded or truncate, base attenuate, narrowly cuneate to rounded, margin plane, secondary veins 1–3 mm apart, held at an angle of 40–65° relative to the midvein, marginal vein 0.5–1.0 mm from the margin, tertiary veins inconspicuous; adaxial surface tomentose, minutely tomentose, pubescent or puberulent when immature, glabrescent to glabrous at maturity, midvein sulcate to flat in the first half and flat in the second half, secondary veins inconspicuous (rarely slightly raised), pellucid dots inconspicuous, less than 5 to more than 15 per mm 2; abaxial surface tomentose or pubescent when immature, pubescent, puberulent or glabrescent to glabrous at maturity, midvein raised, secondary veins inconspicuous (rarely slightly raised), pellucid dots slightly conspicuous to inconspicuous, from 5 to 15 per mm 2; petiole 2–12 × 1–2 mm, canaliculate, tomentose, minutely tomentose or pubescent when immature, tomentose, puberulent or glabrescent to glabrous at maturity. Inflorescence 1.5–6.0 × 0.5–2.5 cm, usually reduced (many times only a dichasia), axillar at the terminal or subterminal nodes, terminal dichasia usually with three flowers, 3–15 flowers, rachis tomentose, minutely tomentose, pubescent or puberulent, 1–6 branching at the base (many times with vegetative branches), sometimes with cataphylls at the base, first internode of central rachis 1–2 mm wide, semicylindrical to flattened, distal internodes flattened, opposite branching, three branching per node, epidermal protrusion present at the nodes. Bract 2–10 × 0.4–2.0 mm, deciduous, lanceolate, oblong or ovate, concave or plane, apex caudate, acuminate or acute, base truncate, adaxial and abaxial surfaces tomentose or puberulent. Pedicel 0–5.6 mm long, cylindrical, tomentose. Bracteole 1.4–6.0 × 0.4–2.0 mm, deciduous, lanceolate, concave (rarely plane), apex caudate, acuminate or acute, base truncate, adaxial surface tomentose, pubescent, puberulent or with scattered trichomes to glabrous, abaxial surface tomentose or puberulent. Floral bud 3–6 × 2–5 mm, turbinate. Hypanthium 0.8–1.4 mm extending above the summit of the ovary, not tearing at anthesis (rarely with a small vertical rupture), externally tomentose or pubescent, glabrescent towards the apex, pellucid dots usually inconspicuous (covered by the indumentum), internally glabrous; calyx 3–5-merous, lobes 0.8–2.8 × 1.0– 3.2 mm, distinct from the hypanthium, deciduous, depressed ovate to ovate, widely deltate or triangular, concave, apex acuminate to rounded, base truncate, externally tomentose or puberulent, internally tomentose, pubescent or puberulent; corolla 4–7-merous, petals light brown to white, 0.8–3.6 × 1.2–4.0 mm, depressed ovate to very widely ovate, concave, apex rounded, base truncate, externally and internally tomentose, puberulent to glabrous; staminal ring 0.4–0.8 mm wide, glabrous, stamens 73–190, filament 2.0– 6.4 mm long, glabrous, anther 0.16–0.48 × 0.24–0.64 mm, square, oblong or transversely oblong; ovary 0.6–1.4 × 0.8–1.8 mm, 2-locular, each locule with 2–9 ovules, style 4.4–6.0 mm long, glabrous, stigma punctiform, papillose. Fruit green to reddish when immature, vinaceous at maturity, 5–12 × 6–12 mm, depressed globose or globose, base rounded, glabrescent to glabrous, remnants of calyx lobes present or not; seeds 1–4.

Distribution and Habitat:— Myrcia subavenia occurs in the Quadrilátero Ferrífero and in the Espinhaço Range (from the South to the Diamantina plateau ), between 1000 to 1550 m (Cerrado domain) ( Figure 10 ). It inhabits the margin of watercourses and patches of soil on rocky outcrops. Berg (1857 –1859) cites in the protologue the type locality as “ Habitat ad ripas prope Timbopeva in prov. S. Pauli ”. However, any specimens from São Paulo state was found and it seems a mistake of the species author; the locality in the label of the type is vague (“Brasilia”).

Phenology:— Flowers were found from August to December and in April, with flowering peak in October. Fruiting specimens were collected from March to May and in January and November (mature fruits in November).

Conservation Status:— The species is found in protected areas and often forms populations with high density, especially in the southern and central parts of its distribution. However, it has an Extent of Occurrence of ca. 5,500 km 2, is recorded from less than 10 localities and field work has showed that the species occurrence is scattered throughout the distribution perimeter. Furthermore, populations in the Serra do Cipó (Minas Gerais state), where a particular morphology is found (see comments below), are in apparent decline; field expeditions to the region did not found specimens in localities with records of about thirty years ago. Thus, the species is considered as Vulnerable (VU, criteria B1a, biii; IUCN 2001).

Discussion:— The species is characterized by a slight keel in immature twig, leaf with flat venation almost always inconspicuous and floral features, which includes: pauciflorus inflorescence (often only one dichasium); bract usually more persistent than the group average; and calyx lobes usually with a prolonged apex. The protologue of Aulomyrcia ferruginea ( Berg 1857 –1859) cites the ovary as 2–3-locular, but only two locular ovaries were found.

Myrcia subavenia has two morphological groups, one linked to the type of Aulomyrcia subavenia and another linked to the type of Aulomyrcia ferruginea . The morphotype related to the type of A. ferruginea has thick branches, evident dichotomic branching ( Figure 3H ), larger leaves, longer inflorescence, calyx lobes with more prolonged apex and multi-ovulate ovary. While the morphotype of A. subavenia occurs from the Quadrilátero Ferrífero to the Diamantina Plateau , the morphotype of A. ferruginea is only found in the Serra do Cipó region.

Such morphological divergences were considered an extreme of variation, because these characteristics are found in specimens from other localities and mixed with typical features of Aulomyrcia subavenia morphotype. For instance, the specimen Mota 2263 (BHCB), from the municipality of Conceição do Mato Dentro, has the typical morphology of A. subavenia but multi-ovulate ovary.

Available illustrations and images: — Morais & Lombardi (2006; as Myrcia lapensis ); Rosa & Romero (2012).

Additional specimens examined: — BRAZIL. Unknown province /state, no date (fl), Martius s.n. ( BR!) . Minas Gerais: Serra do Cipó , 2 January 1987 (fr), J.R.Stehmann 926 (BHCB!, ICN!) . Mun. Catas Altas, RPPN Parque do Caraça , 1550 m, 20 ° 5’33, 9”S, 43 ° 28’27,6”W, 20 April 2004 (fr), P.O.Morais 169 ( BHCB!) ; ibidem, 1550 m, 20 ° 5’33, 9”S, 43 ° 28’27,6”W, 20 April 2004 (fr), P.O. Morais 170 ( BHCB!) ; RPPN Parque Natural do Caraça , 9 May 2003 (fr), P.O.Morais 150 ( BHCB!) . Mun. Conceição do Mato Dentro, Parque Natural Municipal do Ribeirão do Campo , 8 November 2002 (fl), R.C. Mota 2263 ( BHCB!) . Mun. Diamantina , 25 January 1978 (fr), G.Hatschbach 40930 (MBM!, RB!, SPF!) . Mun. Felício dos Santos, APA Felício, 1320 m, 18 ° 17’0”S, 43 ° 28’0”W, 29August 2008 (fl), P.L. Viana 3668 (BHCB!, HRCB!) . Mun. Jaboticatubas , 29 October 1973 (fl), J.Semir CFCR4709 (SP!, UEC!) . Mun. Ouro Preto , 13 October 1988 (fl), M.Peron 716 (RB!, SPF!) ; APA da Cachoeira das Andorinhas , 1397 m, 20 ° 22’9,3”S, 43 ° 30’21,7”W, 10 November 2010 (fl), M.F. Santos 585 (BHCB!, K!, NY!, RB!, SPF!) ; Serra de Antônio Pereira , 5 December 2007 (fl), M.C.T.B. Messias 1649 ( BHCB!) . Mun. Santa Bárbara, Serra do Caraça , 7 March 1982 (fr), N.Hensold CFCR2914 (BHCB!, SPF!) ; ibidem, 7 March 1982 (fr), N. Hensold CFCR2915 (ICN!, SPF!) ; ibidem, 7 March 1982 (fr), N. Hensold CFCR2916 (BHCB!, SPF!) . Mun. Santana do Pirapama, Serra do Cipó , 1337 m, 18 ° 54’57,76”S, 43 ° 44’57,75”W, 24 November 2009 (fr), D.C.Zappi 2574 (K!, SPF!) . Mun. Santana do Riacho , 5 October 1981 (fl), A. Furlan CFSC7500 (RB!, SPF!) ; ibidem, 1 September 1986 (fl), C. Kameyama CFSC9864 (K!, SPF!) ; ibidem, 25 October 1974 (fl), G. Hatschbach 35337 (C!, G!, MBM!, SPF!) ; ibidem, 6 October 1981 (fl), I. Cordeiro CFSC7524 (ICN!, K!, NY!, RB!, SPF!) ; ibidem, 5 November 1983 (fl), M.L. Kawasaki CFSC9150 ( SPF!) ; ibidem, 5 December 1981 (fl), N. Hensold CFSC7708 (BHCB!, F!, G!, ICN!, MBM!, RB!, SP!, SPF!) ; ibidem, 23 October 2001 (fl), R.C. Strassburg 7 (K!, SP!, SPF!, UB!) ; Serra do Cipó , 4 September 1973 (fl), J.Semir CFSC4389 (SP!, SPF!) ; ibidem, 1045 m, 19 ° 16’53,4”S, 43 ° 34’59,3”W, 20 October 2011 (fl), M.F. Santos 715 (BHCB!, K!, NY!, RB!, SPF!) ; ibidem, 1045 m, 19 ° 16’53,4”S, 43 ° 34’59,3”W, 20 October 2011 (fl), M.F. Santos 717 (BHCB!, K!, RB!, SPF!) ; ibidem, 1100 m, 19 ° 17’40”S, 43 ° 36’0”W, 3 November 1981 (fr), N. Hensold 441 (NY!, RB!, SPF!) . Mun. São Gonçalo do Rio Preto, Parque Estadual do Rio Preto , 18 ° 7’0”S, 43 ° 21’0”W, 8 April 2000 (fr), J.A.Lombardi 3800 (BHCB!, SP!) ; ibidem, 18 ° 0’0”S, 43 ° 20’0”W, 5 April 2003 (fl), J.A. Lombardi 5228 (BHCB!, MBM!, SPF!) . Total : 29 specimens .

Figures

FIGURE 3. A. Detail of the leaf of Myrcia summa showing foveolate dots (Prance 29040 [RB]). B. Wax peeling (white) on the leaf of Myrcia rupestris (Santos 641 [SPF]). C. Wax peeling (white) on the leaf of Myrcia costeira (Santos 851 [SPF]). D. Keeled twig of Myrcia costeira (Santos 851 [SPF]). E. Keeled twig of Myrcia densa (Santos 643 [SPF]). F. Leafy cataphyll of Myrcia subcordata covering immature leaves (Rochelle 55 [SPF]). G. Leafy cataphyll (indicated) of Myrcia costeira (Santos 851 [SPF]). H. Scale-like cataphyll (indicated) of Myrcia subavenia (Santos 715 [SPF]). Scales:A=4 mm; B–H=1 cm.

FIGURE 10. Distribution of Myrcia ascendens (triangles), Myrcia subavenia (circles) and Myrcia subterminalis (squares). Continuous lines represent South American country and Brazilian state boundaries. The grey gradient represents elevation.

FIGURE 43. Images of representative specimens of Myrcia sect. Sympodiomyrcia species: Myrcia subavenia (Santos 585 [SPF]).

FIGURE 44. Images of representative specimens of Myrcia sect. Sympodiomyrcia species: Myrcia subavenia (Santos 715 [SPF]).