Chusquea mirabilis A.C. Mota, R.P. Oliveira & L.G. Clark, 2014

Chusquea mirabilis A.C. Mota, R.P. Oliveira & L.G. Clark View in CoL , sp. nov. Figs. 2–4 View FIGURE 2 View FIGURE 3 View FIGURE 4 .

Chusquea mirabilis differs from other species of this subgenus by the presence of branches with sericeous girdles.

Type:— BRAZIL. Bahia: Boa Nova, Fazenda São José, a 8,8 km de Boa Nova, na estrada para Dário Meira, a 1,4 km do ramal à esquerda , 14°24’14”S, 40°9’16”W, 850 m, 7 March 2003 (fl), S.C. Santana, J.L. Paixão, P. Fiaschi & R. Querino 1082 (holotype HUEFS! GoogleMaps , isotypes CEPEC! GoogleMaps , NY! GoogleMaps , SPF! GoogleMaps ).

Culms 0.15–0.6 cm in diameter, 4–8 m long, scandent and clambering. Internodes 20–41 cm long, terete, glabrous, blackened or with irregular black splotches. Culm leaves 14.5–32 cm long, persistent, juncture of sheath and blade abaxially obscure; sheaths 13.6–30.5 cm long, 15.1–20.3 times as long as the blade, abaxially retrorsely scabrous, midrib abaxially prominent toward the apex, margins glabrous; blades 0.9–1.5 cm long, narrowly triangular, erect, permanent, adaxially scabrous, abaxially scabrous, midrib abaxially prominent, apex acute, margins glabrous; girdles 2–4 mm long, scabrous, brown; inner ligules 0.1 mm long, truncate, glabrous. Nodes at mid-culm with one dome-shaped central bud subtended by 18–40 smaller subsidiary buds in two rows, in a constellate arrangement; sheath scar more or less horizontal but dipping strongly below the bud/branch complement; supranodal ridge visible but not prominent. Branching infravaginal; central branch usually developed, as robust as the main culm; leafy subsidiary branches 18–40 per node, 17–24 cm long, 0.5 mm in diameter, geniculate, no rebranching, girdles straw-colored to black-brown, sericeous. Foliage leaves 7–11 per complement; sheaths weakly striate, strongly keeled toward the apex, pilose, usually uniformly light brown, the overlapping margin ciliate or only a tuft of cilia ca. 1 mm long present on each side of the sheath summit, summit extension minimal, to 0.2 mm long; blades 6–13 cm long, 0.35–0.55 cm wide, L:W = 17.1–23.6, linear-lanceolate, adaxially sparsely pilose, abaxially sparsely pilose at the midrib with a tuft of hairs, not tessellate, adaxially green, abaxially glaucous, midrib slightly excentric, adaxially distinguishable at the base, abaxially yellowish and prominent for most of the length toward the apex, base often slightly asymmetrical, rounded-attenuate, apex acuminate, the margins scabrous; pseudopetioles ca. 1 mm long, scabrous, otherwise green, pulvinus absent; outer ligules 0.2 mm long, unlobed to weakly bilobed, erect, extending to the margins along the juncture with the inner ligule, glabrous; inner ligules 0.2 mm long, truncate, glabrous. Synflorescences 2.5–4 cm long, 1–2 cm wide, open, paniculate, just fully exserted from the subtending leaf, not subtended by a spatheate bract; main axis angular, straight, usually glabrous; primary branches ca. 1 cm long at the base, angular, glabrous, usually basally swollen and spreading, the lowermost one subtended by an acuminate bract ca. 1 mm long, otherwise the branches ebracteate; peduncles 1–1.5 mm long, angular, glabrous, slightly swollen immediately below the spikelet, usually basally swollen and spreading. Spikelets 5.9–6.2 mm long, laterally compressed; glumes I and II acute to more commonly shortly subulate, slightly keeled, abaxially scabrous, with ciliolate margins, 1 or 3-nerved; glume I 0.8–1 mm long, 0.14–0.16 times the length of the lemma; glume II 1–1.2 mm long, 0.16–0.2 times the length of the lemma; glumes III and IV subulate, abaxially scabrous, ciliate in the margins; glume III 2–2.1 mm long, 0.34 times the length of the lemma, 5-nerved; glume IV 3–3.4 mm long, 0.5–0.56 times the length of the lemma, 5-nerved; lemma 5.9–6.1 mm long, acute, abaxially scabrous, ciliate in the margins 9-nerved, margins slightly fused at most at the apex; palea 5.9–6.2 mm long, + equaling the lemma, bimucronulate, abaxially scabrous, 2-nerved, 2-keeled, sulcate only toward the apex, the sulcus glabrous. Lodicules 3, glabrous; the anterior pair 0.5 mm long, the posterior one 1.0 mm long. Stamens 3; anthers ca. 2 mm long. Fruit not seen.

Etymology: —The specific epithet refers to the beautiful specimens of this species as seen in its natural habitat.

Comments: —This new species can be considered morphologically similar to Chusquea oligophylla due to the presence of irregular black splotches on the culms and branches, originating from an association with a fungus and previously noted only in C. oligophylla . In addition, these species share morphologically similar spikelets, both in length and proportion of the glumes, lemma and palea. The new species differs from C. oligophylla and other members of the subgenus Rettbergia by its sericeous girdles, which can be easily observed both in the field and in herbarium specimens. In addition to this diagnostic character, it can be differentiated from C. oligophylla by the linear-lanceolate blades foliage leaves (versus lanceolate) and paniculate synflorescences bearing only primary branches (versus paniculate synflorescences with primary and secondary branches in C. oligophylla ) ( Table 1 View TABLE 1 ).

Geographic Distribution and Habitat: — Chusquea mirabilis is apparently endemic to Southeast Bahia State, Brazil, occurring in montane Atlantic Rainforest at 600–900 m elevation.

Conservation Status: —This species must be considered EN B2ab(iii) based on the existence of only three known populations with an area of occupancy smaller than 500 km 2 and the continuing decline projected in quality of habitat ( IUCN 2013).

Phenology: —Three flowering events were recorded for Chusquea mirabilis in 2001, 2003 and 2007. This does not appear to represent a gregarious flowering pattern, since the different populations flowered at different times. In one of the populations sampled (from Boa Nova), individuals were collected in the same year in both vegetative and reproductive phases.

Additional Specimens Examined: — BRAZIL. Bahia: Amargosa, Serra do Timbó, Fazenda do Sr. Arlindo , 16 November 2007 (fl), Ferreira et al. 1785 ( CEPEC) ; Boa Nova, Fazenda São José, 8.8 km de Boa Nova, na estrada para Dário Meira, a 1.4 km do ramal à esquerda , 14°23’74”S, 40°8’76”W, 850 m, 7 January 2001 (fl.), Amorim et al. 3601 ( CEPEC) ; Fazenda Farofa (Dr. Mauro), estrada entre Boa Nova e Dário Meira, ca. 9,5 km de Boa Nova, entra em ramal à direita e anda mais 2 km , 14°25”13”S, 40°7’22”W, 797 m, 23 Oct 2007 (fl), Ferreira et al. 1616 ( CEPEC) ; Fazenda Farofa (Dr. Mauro), estrada entre Boa Nova e Dário Meira, ca. 9,5 km de Boa Nova, entra em ramal à direita e anda mais 2 km , 14°25”13”S, 40°7’22”W, 915 m, 24 October 2007, Ferreira et al. 1669 ( CEPEC) ; ca. 9 km a partir de Boa Nova pela rodovia BA-030 em direção a Dário Meira, entrando à esquerda na fazenda Liberdade e percorrendo ca. 2 km , 14°25'10.14''S, 40°07'17.89''W, 809 m, 15 February 2011, Mota & Carvalho-Sobrinho 399 ( HUEFS) GoogleMaps ; Fazenda São José, 8.8 km east of Boa Nova then 1.4 km north on Fazenda road , 14°23.42’S, 40°08.765’W, 850–1000 m, 14 October 2000, Thomas et al. 12252 ( CEPEC, NY) GoogleMaps ; Fazenda São José entrance 8.8 km E of Boa Nova on road to Dário Meira , 14°23.630’S, 40°08.722’W, 860–900 m, 25 October 2001, Thomas et al. 12634 ( CEPEC, NY, SP) GoogleMaps ; Brejões, Fazenda Lagoa do Morro , 13°5’59”S, 39°54’7”W, 882 m, 17 November 2007, Ferreira et al. 1884 ( CEPEC) GoogleMaps ; Fazenda Lagoa do Morro , 13°5’59”S, 39°54’7”W, 882 m, 17 November 2007, Ferreira et al. 1885 ( CEPEC) GoogleMaps .