Myrcia macrocalyx Faria & Soares-Silva. A. Diaphanized 2015, sp.nov.
Creators: name: Faria, Jair Eustáquio Quintino De
name: Gomes-Bezerra, Kadja Milena
name: Zanatta, Maria Rosa Vargas
name: Júnior, Manoel Cláudio Da Silva
name: Soares-Silva, Lucia Helena
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Myrtaceae
Myrcia
Myrcia macrocalyx

description: Myrcia macrocalyx Faria & Soares-Silva, sp.nov.
TYPE:— BRAZIL. Goiás: Cavalcante, margem da estrada, próximo a entrada para a comunidade Kalunga Engenho II, 13 o 39’43”S, 47 o 28’34”W, 1094 m, 13 May 2012, J.E.Q. Faria et al. 2657 (holotype UB!, isotypes CEN!, HUEFS!, K!, RB!, SP!). Figures 1 and 2.
Myrcia macrocalyx is closely related to Myrcia goyazensis, from which it can be distinguished by the linear to linear-lanceolate leaves, fewer secondary veins (23–30 pairs) diverging from the midvein at 30º–50º angles, bracteoles 10–13 × 2–4 mm, longer calyx lobes (5–9 mm), and 199–206 stamens; while Myrcia goyazensis presents elliptic to oblong leaves, 38–40 pairs of secondary veins diverging from the midvein at 60º–70º angles, bracteoles 3.5–4 × 2–2.5 mm, shorter calyx lobes (4.2–4.5 mm), and 255–296 stamens.
Subshrub up to 0.5 m tall, xylopodiferous, glabrous except for juvenile twigs, petiole, inflorescence rachis, bracts, bracteoles, and abaxial surface of calyx-lobes pubescent; brown twigs becoming glabrous and exfoliating with age. Juvenile twigs somewhat flat with white trichomes 0.2–0.9 mm long. Leaves linear to linear-lanceolate, lustrous on adaxial surface at maturity, 1.2–3.8 × 0.1–0.5 cm, 6–16 times as long as wide, green-yellowish in dried material,translucid punctuations more evident on the abaxial surface, venation reticulate, brochidodromus; blade coriaceous at maturity; apex acute or long acuminate, sometimes apiculate; base acute to attenuate; midvein flat to slightly raised on the adaxial surface and prominent on the abaxial one; secondary veins 23–30 pairs, evident on both surfaces and diverging from the midvein at 30º–50º angles; marginal vein 0.1–0.3 mm from the whitish and thickened margins; petioles adaxially flat, 1–1.5 × 0.5–1.0 mm. Inflorescence consisted of a single terminal flower or rarely a botryoid with up to 5 flowers; bracts lanceolate 11–16 × 3–4 mm, persistent after anthesis; pedicels 0.7–8.6 × 0.5–0.9 mm; bracteoles, ovate to lanceolate, 10–13 × 2–4 mm, caducous or rarely persistent, in this case up to 15 mm in immature fruits; flower buds globose, 5–6 mm in diameter; calyx lobes 4–5, ovate to lanceolate, concave, unequal in size, the largest and external ones 6–9 × 3–5 mm, the smallest and internal ones 5–6.5 × 3–4 mm, sparsely tomentose externally and glabrous internally; petals 4–5, orbicular and concave, margin involute, 6–6.8 × 4–6 mm, pubescent at base and central vein on abaxial surface; staminal ring pubescent, c. 4.5 mm in diameter; stamens inflexed in the bud, about 199–206, filament 8.8–8.9 mm, anthers oblong with a gland next to the connective apex, the gland black when dry; style glabrous, 7.7–7.9 mm; hypanthium densely cano-velutinous, about 1.5–3 mm long; ovary bilocular, 2–3 ovules per locule on a central placenta. Fruits globose to elliptic, sparsely pubescent with slightly protruding glands, 7.8–10.6 × 5.5–11 mm; seeds 1–3, C-shaped to globose, 7.6–8.4 × 5.9–6.7 mm, light brown, testa lustrous and easily detachable; embryo with scattered glandular slightly protruding dots, foliaceous contortuplicated cotyledons (myrcioid type), hypocotyl visible.
Habitat and distribution:— Myrcia macrocalyx is a small subshrub, growing in sandy soils of wet grasslands; currently it has been collected only in the municipality of Cavalcante, Goiás (Figure 3).
Phenology:—Flowering specimens were collected from March to June; fruiting specimens were collected from March to June and November.
Etymology:—The specific epithet alludes to the calyx with large lobes, a distinctive characteristic of this species.
Conservation status:—The geographic range (B) is based on the extent of occurrence (EOO = 154.73 km ²), area of occupancy (AOO = 16 km ²) (GeoCAT 2014), as well as the low number of known populations and indicates that Myrcia macrocalyx may be scored as an endangered species (IUCN category EN), since it fulfills conservation criteria B1ab(i,ii,iii) + 2ab(i,ii,iii) (for more details on these criteria see IUCN, 2010).
Despite the species regional occurrence in the surrounding areas of the “Chapada dos Veadeiros” National Park, there are no records of specimens collected in this conservation unit.The lack of formal protection, its limited associated natural environment (wet clean grasslands), and also its restricted occurrence area suggest that the EN category should be maintained until further studies. Figure 4.
Foliar architecture:—leaves show a pinnate-brochidodromous venation pattern (Figure 5A, B) with visible 5 th order veins; 20–28 2 nd order vein pairs, conspicuous on both surfaces, diverging from the midvein at 30–50˚ angles; intramarginal vein with obtuse angle at ending, 0.1–0.3 mm from the margins (Figure 5B); branched intersecondary admedial veins (Figure 5B); alternate percurrent tertiary veins; polygonal areoles, 0.3–0.5 mm, 4–5(–6) sides, 190– 220/cm 2; veinlets simple to lax branched; marginal vein in loops from the base (Figure 5A).
Scanning Electronic Microscopy:—hipostomatic leaves (Figure 5C), stomatic crest (Figure 5D); granular epicuticular wax on both surfaces (Figure 5E, F); simple trichome and tectors on the abaxial surface of mature leaves (Figure 5C, D) and on both juvenile leaf surfaces. S-type colleters (Lersten 1974) at the bracteoles (Figure 5G). In polar view pollen grains exhibit triangular angles (Figure 5H); are oblate-spheroidal in equatorial view (P/E=0.92) with an irregular, parasyncolpate and verrucose surface.
Comments:—This species is related to Myrcia goyazensis Cambessèdes (1833: 305), but differs from the latter by its linear leaves, short petiole, isolated terminal flowers or rarely botryoids, a velutinous hypanthium and longer calyx lobes. It also resembles Myrcia lignosa Villarroel & Proença (2013: 261) mainly in the linear leaves and isolated flowers, but Myrcia lignosa exhibits more inconspicuous venation; smaller size of bracteoles (3–7 × 0.5–1 mm) and calyx lobes (2–4 × 1.5–2.5 mm), and fewer stamens (95–115) than Myrcia macrocalyx.
Paratypes:— BRAZIL. Goiás: Cavalcante, margem da estrada, próximo à entrada para a comunidade Kalunga Engenho II, 13 o 39’43”S, 47 o 28’34”W, 1094 m, 13 May 2012, fl., K.M. Gomes-Bezerra et al. 47 (UB!); ibidem, fl., K.M. Gomes-Bezerra et al. 48 (E!, UB!); ibidem, fl., K.M. Gomes-Bezerra et al. 49 (IBGE!, UB!); ibidem, fl., K.M. Gomes-Bezerra et al. 50 (UB!); ibidem, fr., K.M. Gomes-Bezerra et al. 52 (RB!, UB!); ibidem, fr., K.M. Gomes-Bezerra et al. 53 (HUEFS!, UB!); ibidem, fr., K.M. Gomes-Bezerra et al. 54 (NY!, UB!); ibidem, fr., K.M. Gomes-Bezerra 55 (MBM!, UB!); ibidem, 20 April 2010, fl. and fr., J.E.Q. Faria et al. 808 (HUEG!, HUEFS!, HUFSJ!, UB!); ibidem, fl., J.E.Q. Faria et al. 809 (UB!); ibidem, fl., J.E.Q. Faria et al. 810 (HUEG!, K!, UB!); ibidem, 4 June 2010, fl. and fr., J.E.Q. Faria et al. 861 (HUFSJ!, K!, RB!, UB!); ibidem, estrada para povoado do Engenho, 13 o 39’15”S, 47 o 28’31”W, 1113 m, 30 March 2011, fl. and fr., J.B. Bringel & H.J.C. Moreira 755 (CEN!, HUFSJ!, UB!); ibidem, Reserva Particular do Patrimônio Natural Serra do Tombador, 13 o 40’01”S, 47 o 48’04”W, 28 October 2010, fr., C.B.R. Munhoz et al. 7950A (RB!, UB!); ibidem, estrada de terra Cavalcante/Kalunga, a 18 Km, 13 o 41’31”S, 47 o 27’57”W, 1063 m, 18 November 2005, fr., T.B. Cavalcanti et al. 3628 (CEN!); ibidem, estrada para Araí, Engenho II, Kalunga, 13 o 37’58”S, 47 o 28’45”W, 1150 m, 14 April 2004, fl., M.L. Fonseca et al. 5128 (IBGE!, RB!); ibidem, estrada para Cavalcante, 6 March 2003, fl., J.F.B. Pastore & E. Suganuma 424 (CEN!); ibidem, caminho para a Cachoeira Santa Bárbara, 20 April 2003, fl., J.F.B. Pastore et al. 558 (CEN!, UB!); ibidem, fr., J.F.B. Pastore et al. 559 (CEN!, UB!); ibidem, fl., J.F.B. Pastore et al. 561 (CEN!, UB!).
description: Published as part of Faria, Jair Eustáquio Quintino De, Gomes-Bezerra, Kadja Milena, Zanatta, Maria Rosa Vargas, Júnior, Manoel Cláudio Da Silva & Soares-Silva, Lucia Helena, 2015, Myrcia macrocalyx (Myrtaceae), a new species from Brazil, with additional morphological highlights, pp. 179-185 in Phytotaxa 234 (2) on pages 181-183, DOI: 10.11646/phytotaxa.234.2.8, http://zenodo.org/record/13632947