Otatea nayeeri Ruiz-Sanchez, 2016

Ruiz-Sanchez, Eduardo & Castro-Castro, Arturo, 2016, Otatea nayeeri (Poaceae: Bambusoideae: Bambuseae: Guaduinae), a new species endemic to Nayarit, Mexico, Phytotaxa 267 (3), pp. 211-218 : 213-215

Otatea nayeeri Ruiz-Sanchez , sp. nov. ( Figs. 1–2 )

TYPE:— MEXICO. Nayarit: Acaponeta, road from Casas Coloradas to San Diego de Alcalá at 500 m aprox. from the intersection of the tres caminos, 770 m a.s.l., 22°26’37.99’’N, 105°10’37.59’’W, 27 November 2014, E. Ruiz-Sanchez & A. Castro-Castro 493 (holotype IBUG!, isotypes ISC!, MEXU!, MO!, US!).

Otatea nayeeri is similar to O. reynosoana and O. transvolcanica , but differs in having thin-papery and deciduous culm leaves; oral setae absent in culm leaves; culm leaf blades that start out erect and become reflexed; developing three subequal branches per node; and having smaller foliage leaf blades lacking fimbriae.

Rhizomes pachymorph with necks 35–74 cm long. Culms 3–6 m tall, 1–3 cm in basal diameter, erect; internodes 8–24 cm long, terete, glabrous, green and pruinose when young, culms with some internode solid and some hollow on the same culm, when hollow then thick-walled. Culm leaves 28.5–63.5 cm long, rectangular, overlapping, deciduous, thin-papery; sheaths 26–41.5 cm long, 5.8–8 cm wide at the base, rectangular, abaxially sparsely pubescent with thick brown-copper hairs, hairs deciduous, margins minutely ciliate, the leaf blades polymorphic in size, the basal leaf blades 2.5–9.5 cm long, triangular, erect, persistent, shorter than the sheaths, abaxially and adaxially glabrous, the margins minutely ciliate, the apex acuminate; the mid-culm leaf blades 10.5–22 cm long, triangular, reflexed, deciduous, shorter than to half the length of the sheath, abaxially glabrous, adaxially pubescent, margins minutely ciliate, apex acuminate; inner ligule a coriaceous rim 0.5–2 mm long, truncate and glabrous; oral setae absent; fimbriae at the summit of the sheath present on both sides, 7–8 mm long, ca. 0.2 mm wide, flat, deciduous, curly. Branching intravaginal; three main branches produced per node, 57–92 cm long, diverging from the main culm at 45 o, and rebranching in second order develop one branch per bud; supranodal ridge pronounced; nodal line horizontal. Foliage leaves 2–4 per complement; sheaths pubescent, rounded on the back with a sheath summit extension on both sides; outer ligule an irregular glabrous rim up to 0.2 mm long with two lobes at the apex, these 0.5–1.5 mm long, 1–1.5 mm wide; inner ligule 0.5–1.5 mm long, truncate, irregular, glabrous; oral setae 3–8 mm long, basally free, flattened, abaxially scabrous, free from the inner ligule, in living specimens the base purple with white tips; fimbriae absent; pseudopetioles ca. 3 mm long, pulvinate at the base, purplish; blades 14.5–23.5 cm long, 1.3–2.1 cm wide, lanceolate, adaxially glabrous, glaucous, abaxially pubescent, green, not tessellate, with a very dense patch of white cilia at the base extending along both sides of the midrib for more than 10 mm, the base attenuate, the apex attenuate-subulate, the margins serrulate. Synflorescences not seen.

Habitat and distribution:— The new species is only known from a few populations in the middle portion of San Pedro River Basin, Nayarit. Otatea nayeeri inhabits savanna-like vegetation sensu Rzedowski (1978) and the ecotone between tropical dry forest and oak-pine forest at elevations of 700 to 1300 m a.s.l., with a mean annual temperature of 24.1 o C and annual precipitation of 1275.2 mm ( SMN 2015). It shares its habitat with Byrsonima crassifolia ( Linnaeus 1753: 462) Kunth in Bonpland et al. (1822: 149), Calliandra laevis Rose (1899: 194) , Cosmos linearifolius (Schultz “Bipontinus” in Seemann 1856: 307) Hemsley (1881: 200), Curatella americana Linnaeus (1759: 1079) , Manfreda rubescens Rose (1903: 22) , Quercus resinosa Liebmann (1854: 182) , Pinus praetermissa Styles & McVaugh (1990: 310) , Salvia aequidistans Fernald (1900: 512) and Zamia paucijuga Wieland (1916: 212) .

Comparison with other species: — On the basis of vegetative morphology, Otatea nayeeri is similar to O. reynosoana and O. transvolcanica . These species are similar in habit, with erect culms, and have similar sizes, forms and colors of the foliage leaves. However, O. nayeeri has thin-papery and deciduous culm leaves, whilst O. reynosoana and O. transvolcanica have thick, hard and persistent culm leaves. Oral setae on the culm leaves are absent in O. nayeeri , but are present and persistent in O. reynosoana , and deciduous in O. transvolcanica . Culm leaf blades are polymorphic in orientation in O. nayeeri , with the basal ones erect and the rest reflexed. In contrast, in O. reynosoana the culm leaf blades are erect, and in O. transvolcanica they are reflexed. In O. nayeeri , branching is intravaginal and three subequal main branches develop per node; Otatea reynosoana has the same branching pattern but develops one or two main branches per node, sometimes three. Otatea transvolcanica has an extravaginal branching pattern, developing one or two main, unequal branches per node, or if three, then the central one is two times wider than the laterals. Number of foliage leaves per complement is 2–4 in O. nayeeri , 4–5 in O. reynosoana and 6–10 in O. transvolcanica . The blades in O. nayeeri are 14.5–23.5 × 1.3–2.1 cm wide, while in O. reynosoana they are 27.5–39 × 0.9–2.1 cm and in O. transvolcanica 34–60 × 2.5–6 cm. The oral setae of the foliage leaves are 3–8 mm long in O. nayeeri , 5–11 mm long in O. reynosoana and 13–21.5 mm long in O. transvolcanica ( Table 2).

Etymology: — The specific epithet honors the Nayeeri (Cora) ethnic group that inhabits the state of Nayarit, Mexico.

Phenology: — This species has never been collected with flowers.

Additional specimens examined (paratypes):— MEXICO. Nayarit: Acaponeta, camino de Casas Coloradas a San Diego de Alcalá a 500 m aprox. del crucero de los tres caminos, 770 m, 22°26’37.19’’N, 105°37’59’’W, 3 July 2014, E. Ruiz-Sanchez & A. Castro-Castro 478 (IEB!); camino de Casas Coloradas a San Diego de Alcalá a 500 m aprox. del crucero de los tres caminos, 770 m, 22°26’37.19’’N, 105°37’59’’W, 27 November 2014, E. Ruiz-Sanchez & A. Castro-Castro 492 (IEB!); km 15 de la brecha entre Santa Cruz de Acaponeta y San Blasito, camino de descenso al Río San Pedro, 880 m, 22°24’59.8’’N, 105°6’8.3’’W, 6 November 2013, A. Castro-Castro et al. 3402 (IBUG, IEB, MEXU!). Nayar, 5–8 km al NW de la Mesa de Nayar, camino a La Mesa del Nayar-Villa de Guadalupe (Cerro Cangrejo), 1300 m, 22°15’N, 104°40’W, 19 September 1989, G. Flores et al. 1123 (MEXU!). This last specimen was cited as a paratype of O. reynosoana ; however, based on a re-examination of this specimen, we found that the morphological characteristics fit O. nayeeri better than they fit O. reynosoana .

Figures

FIGURE 1. Otatea nayeeri. A. Thin-papery and deciduous culm leaf, abaxial view, showing reflexed leaf blade. B. Reflexed leaf blade detail. C. Culm leaf, adaxial view, showing erect leaf blade. D. Abaxial detail of culm leaf pubescence. E. Detail of the culm leaf fimbriae. F. Hollow culm showing intravaginal branching, foliage leaf complement and three main subequal branches per node. G. Second order of ramification, showing one branch. H. Dorsal view of the ligular area showing outer ligule, patch of cilia on the abaxial side with pubescence on the leaf blade and sheath and oral setae. I. Lateral view of the ligular area showing pubescent sheaths and leaf blade, irregular lobes of the outer ligule and oral setae. Drawing by Alfonso Barbosa based on E. Ruiz-Sanchez & A. Castro-Castro 493.

FIGURE 2. Otatea nayeeri. A. Single culm showing branches and foliage leaf complements. B. Mid-culm section, showing three main subequal branches. C. Foliage leaf complement showing glaucous leaves. D. Ligular foliage leaf blade area, white arrow indicates oral setae. E. Culm leaves, white arrow indicates erect culm blade at basal node. F. Mid-culm leaves, white arrow indicates reflexed culm blade. Photos A, B and D correspond to the voucher E. Ruiz-Sanchez & A. Castro-Castro 493; photos C, E and F correspond to the voucher E. Ruiz-Sanchez & A. Castro-Castro 492. Photos by E. Ruiz-Sanchez.