Chusquea caparaoensis L.G. Clark (1992: 408)

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, Phytotaxa 358 (3), pp. 235-250 : 236-239

Chusquea caparaoensis L.G. Clark (1992: 408) . ( Figs. 1 F ‒ I , 3 F ‒ J )

Type:— BRAZIL. Minas Gerais: Mun. Caparaó, Parque Nacional do Caparaó, trail to Pico da Bandeira, just above turnoff to Vale Encantado, 2070 m, 23 February 1990, Clark & Morel 701 (holotype SP!, isotypes BHCB!, ISC!, K!, MO!, NY!, RB!, US!).

Culms 1.5–3.5 cm in diameter, 4.5 ‒ 6 m tall, caespitose, more or less erect, arching at the apex; internodes (10–) 12–16 (–21.5) cm long, terete, glabrous, waxy. Culm leaves (12.4–) 14.5–22 cm long, caducous; the juncture of the sheath and blade abaxially an obscure line or inverted “V”; sheaths 10–16 cm long, 2.8 ‒ 5.4 (–7) times as long as the blade, more or less rectangular, narrowing toward the apex, with the width of the base more than 2 times the width at the apex, abaxially retrorsely scabrous to papillose, abaxially glabrous, the margins ciliate near the apex and glabrous elsewhere, or completely glabrous, sheath summit extension 0 ‒ 2 mm long; blades (1.6–) 3–4.2 (–5.7) cm long, triangular, as long as or, more commonly, longer than wide, erect, persistent, adaxially strigillose to strigose, at the base and the apex, sparsely strigillose or glabrous in the middle, abaxially strigose, midrib evident only near the apex, apex navicular, mucronate, margins glabrous, base not pseudopetiolate; girdles 0.5 ‒ 2 mm long, glabrous; inner ligules 2 ‒ 3 mm long, erose, ciliolate. Nodes slightly swollen; central bud triangular, subtended by (8 ‒) 15 ‒ 19 smaller subsidiary buds, in 1 ‒ 2 rows, in a constellate array, 2 subsidiary buds more robust and larger, partially flanking the base of the central bud, 3 ‒ 5 medium sized subsidiary buds and (4 ‒) 8 ‒ 13 smaller subequal subsidiary buds; nodal line (sheath scar) more or less horizontal or dipping slightly below the bud/branch complement; supranodal ridge prominent. Branching modified extravaginal; central branch 68 ‒ 86 cm long, curving upwards, away from main culm at a 30° ‒ 50° angle, nodding from the middle, or ascending, rebranching from the second or third nodes; 11 ‒ 34 subsidiary branches per node, 2 robust and subequal to central branch, (25 ‒) 40 ‒ 68 cm long, rebranching, 3 ‒ 4 medium-sized, (20 ‒) 30 ‒ 45 cm long, initially curving upwards and nodding at the ends, rebranching, (8 ‒) 15 ‒ 30 small sized subsidiary branches 18 ‒ 26 cm long, rebranching or not, slightly ascending or horizontally disposed. Foliage leaves (5 ‒) 8–11 per complement; sheaths deciduous, uniform in color, strigillose, nerves prominent, margins glabrous, summit extension less than 0.5 mm long; outer ligule ca. 0.1 mm long, a minute rim, glabrous; inner ligule ca. 0.5 mm long, slightly rounded to truncate, glabrous pseudopetiole 0.5–0.8 (‒ 1) mm long, distinct, glabrous; blades (4.5 ‒) 5.6–6.8 cm long, 0.18–0.25 cm wide and L:W = (22.5 ‒) 25.6 ‒ 33 on vegetative branches, (3 ‒) 3.5 ‒ 4.5 (‒ 5) cm long, (0.15 ‒) 0.2 ‒ 0.27 cm wide and L:W = 15–20 (‒ 23.6) on reproductive branches, adaxially scaberulous over some veins, or completely glabrous, abaxially glabrous, striate, the base attenuate, apex subulate, margins scabrous. Synflorescences (2 ‒) 2.7 ‒ 5.2 cm long, 1.2 ‒ 1.6 cm wide, paniculate, narrow, base retained within the subtending sheath; rachis and branches angular, scaberulous, not glaucous; branches 1 ‒ 2.4 cm long, appressed; pedicels (1.1 ‒) 2 ‒ 4.9 mm long, angular, scaberulous, glaucescent to glaucous at the apex. Spikelets (6 ‒) 7 ‒ 8.2 (‒ 9) mm long, 1.2 ‒ 1.6 mm wide, more or less terete; glumes I and II scalelike, abaxially glabrous, nerves absent, margins glabrous, partially glaucous; glume I 0.1 ‒ 0.3 mm long, less than 1 / 30 (‒ 1 / 20) the spikelet length; glume II 0.3 ‒ 0.4 (‒ 0.5) mm long, 1 / 25 ‒ 1 / 15 the spikelet length; glumes III and IV abaxially sparsely scaberulous near and along the midvein or completely glabrous, slightly keeled; glume III (2.4 ‒) 2.8 ‒ 4 mm long including the awn, 2.1 ‒ 3.1 mm long excluding the awn, 2 / 5 ‒ 3 / 5 the spikelet length, short-awned, awn (0.4 ‒) 0.7 ‒ 1 mm long, (1 ‒) 3-nerved, sometimes the secondary nerves very faint, adaxially pubescent on the upper ½ or less, glabrous elsewhere, ciliolate on the upper ¼ of the margin, or less; glume IV (2.8 ‒) 3 ‒ 4.2 (‒ 4.8) mm long including the awn, (2.4 ‒) 3.1 ‒ 3.9 mm long excluding the awn, ½ ‒ 3 / 5 times the spikelet length, apex short-awned to awned, awn 0.4 ‒ 0.7 (‒ 0.9) mm long, 3 (‒ 5)-nerved, sometimes with obscure secondary nerves, adaxially pubescent on the upper 1 / 3 and glabrous elsewhere, ciliolate on the upper 1 / 5 of the margin or glabrous; lemma (5.3 ‒) 6 ‒ 8.2 (‒ 9) mm long, including the mucro, mucronate, 7, (8) or 9-nerved, keeled, abaxially incanous, adaxially puberulent on the upper 1 / 10 and glabrous elsewhere, apically ciliolate; palea (5.3 ‒) 6 ‒ 6.9 (‒ 8.8) mm long, subequal to the lemma, bimucronulate, abaxially incanous, adaxially pubescent on the upper 1 / 10, 4-nerved, slightly 2-keeled, sulcate only toward the apex, ciliolate on the upper 1 / 5 of the margin or less. Lodicules 3, glabrous, ciliate; the anterior pair ca. 0.9 ‒ 1.53 mm long, the posterior one 0.8 ‒ 1.2 mm long. Stamens 3, anthers 1.2 ‒ 3 mm, yellow. Fruit unknown.

Comments: —The species most similar to Chusquea caparaoensis are C. fruticosa (see Table 1 and comments for this species) and C. riosaltensis (sect. Swallenochloa ). Foliage leaves of C. riosaltensis are similar to those of C. caparaoensis , but foliage leaves of C. riosaltensis have persistent sheaths and a smaller L:W ratio (10 ‒ 13). Chusquea riosaltensis has intravaginal branching, whereas C. caparaoensis has modified extravaginal branching.

Spikelets of Chusquea caparaoensis are similar to those of species placed in C. nudiramea informal group, but it can be distinguished from C. juergensii by its narrower spikelets (1.2–1.6 mm vs. 1.5–2.3 mm) and the palea subequal to the lemma (vs. palea overtopping the lemma); from C. nudiramea by its shorter lemmas (5.3–7.0 mm vs. 7.9–8.3 mm), lemma apex (mucronate vs. subulate) and shorter paleas (5.3–6.9 mm vs. 7.6–7.9 mm); and from C. fruticosa by its relatively shorter glume IV and shorter glume IV awn (see Table 1 and comments for this species). Most of the spikelets examined by Pianissola did not have developed stamens, but in their place a filiform structure was seen. We are not sure how to interpret this structure, but perhaps it represents a developmental anomaly or the effect of some pathogen.

Phenology: —A gregarious flowering event was recorded in 2015 at the Parque Nacional do Caparaó, for the first time for C. caparaoensis . No other records of reproductive events were found among the specimens examined, and for that reason the flowering cycle of this species is unknown.

Geographic distribution and habitat: — Chusquea caparaoensis is known only from the Parque Nacional do Caparaó ( Fig. 5 ), where it occurs in a transitional zone between the upper montane forest and high altitude grassland habitats, on rocky outcrops or in rocky soils. Its elevational distribution ranges from 1777 to 2100 m.

Conservation status: —We applied the IUCN (2016) criteria and propose an IUCN red list category of vulnerable (VU = D2) given that the low number of locations in the same conservation unit is less than five.

Additional specimens examined:— BRAZIL: Minas Gerais: Alto Caparaó, Parque Nacional do Caparaó, Vale Encantado , 2002 m, 20°24.666’S, 41°50.047’W, 9 April 2015, Pianissola et al. 80 (VIC) ; ibid., 2042 m, 20°24.717’S, 41°50.012’W, 9 April 2015 (fl.), Pianissola et al. 81 (VIC) ; Cachoeira Bonita , 1777 m, 20°24’23.4”S, 41°50’13.4”W, 17 August 2015, Pianissola et al. 115 (VIC) ; Vale Encantado , 1880 m, 20º0.5’38.4”S, 43º28’45.2”W, 8 April 2016, Pianissola et al. 132 (VIC), ibid., 1875 m, 20º0.5’38.4”S, 43º28’45.2”W, 8 April 2016, Pianissola et al. 133 (VIC) ; ibid., 1854 m, 20º0.5’38.4”S, 43º28’45.2”W, 8 April 2016, Pianissola et al. 135 (VIC); ibid., 1879 m, 20º0.5’38.4”S, 43º28’45.2”W, 8 April 2016, Pianissola et al. 136 (VIC) ; trilha para o Pico da Bandeira , 1855 m, 22 December 2006, Viana et al. 2528 (BHCB) ; Caparaó, Parque Nacional do Caparaó , próxima a Tronqueiras, Hatschbach et al. 55481 (ISC, MBM) .

Figures

FIGURE 1. Chusquea fruticosa and Chusquea caparaoensis. A–E Chusquea fruticosa (Pianissola & Silva 116) A. Culm leaf. B. Branch complement. C. Bud complement. D. Flowering branch with foliage leaves and inflorescence. E. Spikelet. F–I Chusquea caparaoensis (F, Pianissola et al. 132 (VIC); G. Pianissola et al. 80, H–I Pianissola et al. 81) F. Seedling. G. Bud complement. H. Flowering branch with foliage leaves and synflorescence. I. Spikelet. Illustration by Reinaldo Pinto.

FIGURE 3.A–E Chusquea fruticosa.A. Habitat. B. Habit.C. Culm leaves.D. Branch complements and foliage leaves.E. Synflorescences and foliage leaves. F–J Chusquea caparaoensis. F. Habitat and habit. G. Branching pattern and foliage leaves. H. Synflorescence and foliage leaves. I. Dead culms. J. Seedling. Photos by Evandro Pianissola.

FIGURE 5. Geographic distribution of Chusquea fruticosa, C. caparaoensis and C. imbricata. The red circle represents the distribution of both Chusquea fruticosa and C. imbricata in the Parque Estadual da Serra do Brigadeiro. The blue square represents the distribution of Chusquea caparaoensis in the Parque Nacional do Caparaó. The gray area represents the Atlantic Forest domain.