Chusquea imbricata Pianiss., L. G. Clark & Santos-Gonc. 2018, sp. nov.
Creators: name: Pianissola, Evandro Machado
name: Parma, Daniele F.
name: Santos-Gonçalves, Ana Paula
name: Clark, Lynn G.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Poales
Poaceae
Chusquea
Chusquea imbricata

description: Chusquea imbricata Pianiss., L.G. Clark & Santos-Gonç. sp. nov. (Figs. 2 A ‒ G, 4 A ‒ E)   
 Type:— BRAZIL. Minas Gerais: Araponga, Parque Estadual da Serra do Brigadeiro, trilha do Carvão, entrando pelo Lado do Pico do Boné, aprox. 200 metros após a Carreta, lado direito da trilha 10 m da trilha, em margem de rio, 1461 m, 20°41.122’S, 42°27.920’W, 14 April 2015 (fl.), Pianissola & Silva 95 (holotype VIC!, isotypes BHCB!, ISC!, RB!).   
 The following set of characters distinguishes this species from all other species placed in Chusquea subgenus Swallenochloa sect. Swallenochloa: Internodes sulcate above the bud/branch complement; culm leaves (20 ‒) 33 ‒ 55 cm long, extending for two to three internodes, caducous, abaxially with setose trichomes at the base; triangular central bud more or less linearly subtended by 5 ‒ 20 subsidiary buds; central branch 47 ‒ 127 cm long; foliage leaf blades 2.5 ‒ 4.1 cm long, 0.15 ‒ 0.28 (‒ 0.35) cm wide and L:W = (8 ‒) 10 ‒ 17.3 on vegetative branches, (1.3 ‒) 1.8 ‒ 2.5 (‒ 6.4) cm long, 0.2 ‒ 0.25 (‒ 0.35) cm wide and L:W = (6.7 ‒) 10 ‒ 15 (‒ 19) on reproductive branches.   
 Culms 0.5 ‒ 2.3 cm in diameter, (2.5 ‒) 5 ‒ 7 m tall, caespitose, erect; internodes 14 ‒ 20 cm long, sulcate above the bud/branch complement, terete elsewhere, pubescent below the nodes when young, glabrous when mature, the sulcus pubescent, waxy elsewhere. Culm leaves (20 ‒) 33 ‒ 55 cm long, extending for the length of two to three internodes, caducous, juncture of sheath and blade abaxially conspicuous, more or less horizontal, slightly rounded or slightly concave; sheaths (12.8 ‒) 28 ‒ 32 cm long, 1.3 ‒ 2.4 times as long as the blade, more or less rectangular, abaxially setose at the base, becoming strigose and strigillose toward the apex, these longer trichomes always intermixed with barbellate trichomes, adaxially glabrous or rarely with small pubescent strips, margins ciliate intermixed with ciliolate hairs, the overlapping margin not fused at the base, sheath summit extension null ‒ 0.3 mm long, ciliate; blades 7.5 ‒ 23 cm long, triangular, erect, persistent; adaxially glabrous or commonly with barbellate and strigillose trichomes at the base and the apex, abaxially strigose or/and strigillose, intermixed with barbellate trichomes, midrib obscure, apex acuminate, the margins sparsely ciliate intermixed with ciliolate hairs, base not pseudopetiolate; girdle absent; inner ligule 0.5 ‒ 1.6 mm long, erose, ciliolate. Nodes slightly swollen; triangular central bud more or less linearly subtended by 5 ‒ 20 subsidiary buds; nodal line (sheath scar) more or less horizontal; supranodal ridge obscure. Branching intravaginal; central branch 47 ‒ 127 cm long, erect or initially erect becoming almost horizontal, rebranching; 14 ‒ 24 subsidiary branches per node, 8 ‒ 68 cm long, erect or initially erect to becoming almost horizontal, rebranching near the base. Foliage leaves 3 ‒ 12 per complement; sheaths persistent, color uniform, finely pubescent to pubescent between the nerves, nerves not prominent, ciliolate on the overlapping margin or rarely ciliolate on both margins, sheath summit extension 0.1 ‒ 0.5 mm long; outer ligule a minute rim, pubescent or rarely glabrous; inner ligule 0.05 ‒ 0.3 mm long, truncate, finely ciliolate pseudopetiole 0.15 ‒ 0.53 mm long, not very distinct, pubescent to sparsely pubescent; blades 2.5 ‒ 4 cm long, 0.15 ‒ 0.28 (‒ 0.35) cm wide and L:W = (8 ‒) 10 ‒ 17.3 on vegetative branches, (1.3 ‒) 1.8 ‒ 2.5 (‒ 6.4) cm long, 0.2 ‒ 0.25 (‒ 0.35) cm wide and L:W = (6.75 ‒) 10 ‒ 15 (‒ 19) on reproductive branches, abaxially glabrous or rarely sparsely pubescent, adaxially pubescent at the base and scabrous above some lateral veins, glabrous elsewhere, not tessellate, striate, base asymmetric or slightly asymmetric, cuneate to narrowly cuneate, apex navicular-subulate to short subulate, margins scabrous. Synflorescences 0.8 ‒ 2.5 (‒ 3.5) cm long, 0.4 ‒ 0.8 cm wide, paniculate, narrow, base retained within the subtending sheath; rachis and branches angular, pubescent, not glaucous; branches 0.7 ‒ 1.7 cm long, appressed; pedicels 1.2 ‒ 4.2 mm long, angular, pubescent to scaberulous, not glaucous. Spikelets 5.1 ‒ 7.1 mm long, 1 ‒ 1.5 mm wide, more or less terete; glume I 0.2 ‒ 0.5 mm long, less than 1 / 12 the spikelet length, scalelike, nerves absent, abaxially pubescent, ciliate, not glaucous; glume II 0.5 ‒ 1.5 (‒ 1.9) mm long, 1 / 10 ‒ 1 / 4 the spikelet length, apex acute to mucronate, 0 ‒ 1-nerved, usually keeled, abaxially pubescent at the apex, ciliate along the upper half of the margin, not glaucous; glumes III and IV abaxially pubescent, keeled; glume III (2.5 ‒) 3 ‒ 4.1 mm long including the awn, (2.5 ‒) 3 ‒ 4.1 mm long, excluding the awn, ½ ‒ 2 / 3 the spikelet length, apex mucronate to awned, awn less than 0.8 mm long, 3- or 5-nerved, adaxially puberulent at the apex, ciliate along the upper half of the margin, not glaucous; glume IV 2.9 ‒ 4.5 mm long including the awn, 2.9 ‒ 4.5 mm long excluding the awn, ½ ‒ 2 / 3 times the spikelet length, apex awned, awn 0.4 ‒ 1 mm long, 5- or 7-nerved, adaxially pubescent at 3the apex, ciliolate along the upper third of the margin, not glaucous; lemma 5.3 ‒ 7 mm long including the awn, mucronate to awned, awn 0.3 ‒ 0.6 mm long, 7-nerved, keeled toward the apex, abaxially puberulent, adaxially pubescent at the apex, ciliate along the upper 1 / 4 ‒ 1 / 3 of the margin; palea 5.3 ‒ 6.8 mm long, subequal to the lemma, bimucronulate, abaxially puberulent, adaxially pubescent at the apex, 4 (6)-nerved, 2-keeled, slightly sulcate only toward the apex, the sulcus puberulent. Lodicules 3, pubescent, ciliate; the anterior pair ca. 1 ‒ 1.7 mm long, the posterior one 0.5 ‒ 1.2 mm long. Stamens 3; anthers ca. 1.9 ‒ 3 mm long, yellow. Fruit unknown.   
 Comments: — Chusquea imbricata is morphologically similar to C. nutans and C. pinifolia because of their narrow foliage leaf blades and overall erect habits. Chusquea imbricata can be easily distinguished from C. nutans by its longer internodes (14 ‒ 20 cm vs. 7.7 ‒ 14 cm), longer culm leaves ((20 ‒) 33 ‒ 55 cm vs. 6.6 ‒ 17 cm) with a rectangular sheath (vs. a triangular sheath) and a conspicuous blade (7.5 ‒ 23 cm long vs. inconspicuous, 0.8 ‒ 2.3 cm long), the culm leaves usually extending the length of two to three internodes (vs. usually extending approximately the length of one internode), the central branch subtended by subsidiary branches (vs. central branch flanked by subsidiary buds/ branches), foliage leaves wider (0.15 ‒ 0.28 (‒ 0.35) cm vs. 0.06 ‒ 0.15 cm) and L:W = (6.75 ‒) 10 ‒ 17.3 (‒ 19) (vs. L:W = 33 ‒ 60), glume I shorter (0.2 ‒ 0.5 mm vs. 0.6 ‒ 0.8), glume IV 5- or 7-nerved (vs. 3-nerved), and the palea 4 (6)-nerved (vs. 2-nerved) with an acute (vs. bimucronulate) apex (Table 2). Morphological differences between C. imbricata and C. pinifolia include the following: the culms of C. imbricata are (2.5 ‒) 5 ‒ 7 m tall (vs. 2 ‒ 3 m tall), its internodes are sulcate (vs. terete) and 14 ‒ 20 cm long (vs. 3 ‒ 11 cm long), its culm leaves are deciduous (vs. persistent) and 20 ‒ 55 cm long (vs. 5.3 ‒ 14.2 cm long), its foliage leaf blades are wider (L:W = (6.75 ‒) 10 ‒ 17.3 (‒ 19) vs. L:W = 17 ‒ 31), and the apex of its glume IV is subulate (vs. mucronate) (Table 2). Similar to Chusquea nutans, C. pinifolia occurs in open habitats, often on rocky outcrops, and similar to C. imbricata, C. pinifolia may occur in marshy or boggy areas (Clark 1992). The intravaginal branching and linearly arranged subsidiary buds place this species within subg. Swallenochloa sect. Swallenochloa, which will now include 33 species.   
 This species was treated as C. aff. nutans in Silva et al. (in press).   
 Phenology: —Three flowering clumps were found in April 2015, but most of the plants in the single known population were vegetative. These observations do not allow us to conclude whether such flowering represented sporadic flowering or whether a gregarious flowering event was starting. This population must be monitored in subsequent years in order to better understand the phenology of C. imbricata.   
 Geographic distribution and habitat: — Chusquea imbricata is known from just one small population, in a boggy area, in a montane Atlantic forest habitat at an elevation near 1460 m. Although we made a concerted effort to locate additional populations of the species during collecting trips to the Parque Estadual da Serra do Brigadeiro, none were found. We also did not find any prior collections of this species in herbaria we visited. This species is apparently narrowly endemic to Parque Estadual da Serra do Brigadeiro (Fig. 5).   
 Conservation status: —We applied the IUCN (2016) criteria and propose an IUCN red list category of critically endangered (CE = B2a) given the low number of locations (i.e., one).   
 Etymology: —The specific epithet of this species refers to the distinctively long culm leaves that extend for two to three internodes of the young culms, with an imbricate arrangement overlapping the culm leaves above.   
 Additional specimens examined:— BRAZIL. Minas Gerais: Araponga, Parque Estadual da Serra do Brigadeiro, trilha do Carvão, entrando pelo Lado do Pico do Boné, aprox. 200 metros após a Carreta, lado direito a 10 m de distância da trilha, 10 September 2013, Picanço et al. 36 (ISC, VIC); ibid., 1461 m, 20°41.122’S, 42°27.920’W, 14 April 2015, Pianissola & Silva 93, 94 and 96 (VIC); ibid., 1464 m, 8 July 2013 (fl.), Silva & Pianissola 263 and 264 (VIC).
description: Published as part of Pianissola, Evandro Machado, Parma, Daniele F., Santos-Gonçalves, Ana Paula & Clark, Lynn G., 2018, Two new species of Chusquea subg. Swallenochloa (Poaceae: Bambusoideae: Bambuseae) from Minas Gerais, Brazil, and complete description of C. caparaoensis, pp. 235-250 in Phytotaxa 358 (3) on pages 241-245, DOI: 10.11646/phytotaxa.358.3.2, http://zenodo.org/record/13703156