Myrcia matogrossensis Faria & Sobral, 2017

Faria, Jair E. Q., Lucas, Eve J. & Sobral, Marcos, 2017, Two New Species of Myrcia (Myrtaceae) from Brazil, Phytotaxa 319 (2), pp. 159-166 : 163-165

2. Myrcia matogrossensis Faria & Sobral , sp. nov. ( Figure 4 ).

Type: — BRAZIL. Mato Grosso : Ribeirão Cascalheira , R-10, c. 12 km SW of base camp, 12°49’ S, 51°46’ W, 20 September 1968, R. M. Harley & R. Sousa 10139 (holotype UB!; isotypes K!, NY, RB) .

Myrcia matogrossensis is apparently related to Myrcia lasiantha De Candolle (1828: 254) from which it is distinguished by its elliptic to lanceolate blades (versus cordiform in Myrcia lasiantha ), with 9–11 lateral veins at each side (vs. 12– 14 veins), inflorescences with solitary flowers, triads and botryoids, these occasionally congested and glomeruliform (vs. thyrsoid) and puberulous fruits (vs. tomentose).

Shrub or tree 1–4 m; trichomes simple, white. Stem with fissurate rhytidome; twigs cinereous, pubescent, internodes 0.2–1.5 cm. Blades elliptic, narrowly elliptic to lanceolate, 0.6–2.1 × 0.3–0.8 cm, 1.6–5.6 times longer than wide, chartaceous to subcoriaceous, usually markedly rugose when dry, adaxially puberulous to glabrescent, sericeous to sericeous-pubescent abaxially; apex acute to obtuse; base subcordate to truncate; venation usually not evident, when visible the midvein glabrescent to pubescent, plane or impressed adaxially and sericeous-pubescent and raised abaxially, lateral veins 9–11 at each side, the marginal vein absent, the loops of the arches of the lateral veins 0.5–0.8 mm from the margin at the medial region; glandular dots dense, raised to plane adaxially, not visible abaxially; petioles absent or 0.5–1 × ca. 0.4 mm, sericeous-pubescent, adaxially sulcate. Inflorescences solitary flowers to triads or botryoids, these occasionally very congested and glomeruliform with 1–5 flowers; peduncles 4–11 mm; rachis absent or 2–8 mm, sericeous-pubescent. Flower buds turbinate, 3–4 × 3–4 mm; bracts linear, lanceolate or elliptic, 3–7 mm, occasionally foliaceous in well-developed inflorescences, with venation visible at least adaxially, persisting after anthesis; pedicels 0–6 mm, sericeous-pubescent; bracteoles linear to lanceolate, apices acute, 3–6 mm, not connate, glabrous adaxially and sericeous abaxially, persisting in fruits; ovary densely sericeous externally; calyx lobes four or five, 1.5–3 × 1.2–1.5 mm, acute, glabrous with raised glandular dots adaxially, sericeous abaxially, the margin ciliate, persisting after anthesis; petals white, obovate to elliptic, rounded or acute at the apex, 2–3 mm, glabrous adaxially and sparsely sericeous abaxially, with raised gland dots on both faces; staminal disk 0.8 mm wide, densely pubescent, slightly depressed, the region between the disc and the style base densely pubescent; stamens 115–148, filaments 4–7 mm, glabrous, anthers elliptic to oblong with one apical gland; style 5–7 mm, sericeous, stigma punctiform; ovary 2- locular with 2 ovules per locule. Fruit elliptic, atropurpureous when mature, 7–9 × 4.5–6 mm, puberulous with raised glands; single seed with crustaceous testa; embryo with two foliaceous cotyledons encircled by a well-developed hypocotyl.

Distribution:— Myrcia matogrossensis is known from the central Brazilian state of Mato Grosso from where it was collected in the municipalities of Barra do Garças, Canarana, Cocalinho, Paranatinga, Querência e Ribeirão Cascalheira ( Figure 3 ).

Habitat:—According to information from available specimens Myrcia matogrossensis occurs in cerrado phytophysionomies such as campo cerrado, cerrado sensu stricto and cerradão (sensu Ribeiro & Walter 2008) on sandy soils.

Phenology:— Myrcia matogrossensis was registered with flowers from July to November and fruits were collected in November and December.

Conservation status:—The six municipalities from where Myrcia matogrossensis was collected have a total area of 89,799 km 2 (IBGE 2016) with 9,891 known collections (CRIA 2016), resulting in an average of 0.1 collections/ km 2 and indicating low collection intensity. Based on the nine collection sites, Myrcia matogrossensis has an extent of occurrence (EEO) of 67,975 km 2 and an area of occupancy (AOO) of 36 km 2. This region is known to be severely fragmented by extensive crops and farming with few natural vegetation refuges. For these reasons Myrcia matogrossensis is here scored as Endangered (EN), fulfilling criteria B2ab (i, ii, iii) of the IUCN (IUCN 2001).

Affinities:— Myrcia matogrossensis is apparently related to Myrcia lasiantha from which it is distinguished by the characters cited in the diagnosis. It is noteworthy that in all specimens the blades are markedly rugose when dry. As described for Myrcia occulta , the combined characters of this species assign it to the informal “clade 5” in the phylogenetic scheme proposed by Lucas et al. (2011).

Etymology:—The specific epithet alludes to the Brazilian state of Mato Grosso from where all known collections of the species were made.

Paratypes:— BRAZIL. Mato Grosso : Barra do Garças , 230 Km along new road NNE of village of Xavantina (30 Km due S of Royal Society-Royal Geographic society Base Camp). 6 Km S of “Córrego dos Porcos”, 12°51’ S, 51°45’ W, 26 November 1969, G. Eiten & L. T. Eiten 9565 ( K!, SP) ; Barra do Garças , R. 10, c. 12 km SW of base camp, near Lago do Leo, 15°51’ S, 52°15’ W, 3 December 1968, R. M. Harley et al. 11283 ( K!, UB!) ; Canarana , vicinity of Garapu, 28 September 1964, G. T. Prance et al. 59153 ( UB!) ; Cocalinho , Fazenda Tracajá, 1 July 2000, J. P. Neto JP-051 ( UB!) ; Paranatinga , Estrada do ribeirão do Grilo, Agrochapada, 31 October 1990, M. Macedo & S. P. Assunção 2944 ( INPA, SP!) ; Querência , 49 km from Canarana on the road to Paranatinga, 12°32’ S, 52°39’ W, 30 August 1997, J. A. Ratter et al. 7831 ( K!) ; Ribeirão Cascalheira , Royal Society and Royal Geographic Society base camp, 12°49’ S, 51°46’ W, 2 October 1967, G. Argent et al. 6598 ( K!, UB!) ; Ribeirão Cascalheira , 250 km along new road NNE of village of Xavantina, 9.8 km due SW of Royal Society and Royal Geographic Society base camp. Along path R-10, 12°51’ S, 51°45’ W, 15 September 1968, G. Eiten & L. T. Eiten 8738 ( K!, UB!) ; Ribeirão Cascalheira , Mato Grosso expedition base camp, Rio Transect, base camp area, 12°49’ S, 51°46’ W, 3 December 1968, R. M. Harley 11526 ( K!) ; Ribeirão Cascalheira , 1 km E. of km 264 Xavantina - Cachimbo road. Transect 750 m. S. from road to base camp, 12°49’ S, 51°46’ W, 14 November 1967, D. Philcox et al. 3014 ( K!, UB!) ; Ribeirão Cascalheira , Transect S from road to basecamp from main Xavantina to Cachimbo road, 252 km N of Xavantina, 15 November 1967, D. Philcox et al. 3032 A ( K!, UB!) ; Ribeirão Cascalheira , roadside, km 272 Xavantina-Cachimbo road, 12°49’ S, 51°46’ W, 16 November 1967, D. Philcox et al. 3078 ( K!, UB!) ; Ribeirão Cascalheira , between km 244 and 264 Xavantina-Cachimbo road, 12°49’ S, 51°46’ W, 12 December 1967, D. Philcox et al. 3468 ( K!, UB!) ; Ribeirão Cascalheira , near the base camp of the Xavantina-Cachimbo expedition, c. 270 km N of Xavantina, 12°54’ S, 51°52’ W, November 1967, J. Ramos & R. Sousa s.n. ( K!) ; Ribeirão Cascalheira , c. 270 km N of Xavantina on the Xavantina-São Félix Road, 12°54’ S, 51°52’ W, 4 July 1968, J. A. Ratter et al. 2076 ( K!, UB!) ; Ribeirão Cascalheira , 2 km E of the base camp of the expedition, c. 270 km N of Xavantina, 12°54’ S, 51°52’ W, 11 July 1968, J. A. Ratter & R. A. R. Castro 2141 ( K!, UB!) ; Ribeirão Cascalheira , 170 km from Nova Xavantina on road to Ribeirão Cascalheira, 13°05’ S, 52°00’ W, 12 April 1996, J. A. Ratter et al. 7468 ( UB!) ; Sem município, arredores da expedição inglesa até o córrego Surucucu, 10 October 1968, S. G. Fonseca & E. Onishi 1362 ( UB!) .

Figures

FIGURE 3. Distribution map of Myrcia occulta and Myrcia matogrossensis in Brazil.

FIGURE 4. Myrcia matogrossensis. A—flowering branch, B—inflorescence detail. (A and B from the holotype)