Una nueva especie de Otatea (Poaceae: Bambusoideae: Bambuseae) de Querétaro México

Eduardo Ruiz–Sánchez^{1, 2}

University of California, Berkeley, Plant and Microbial Biology, 431 Koshland Hall, Berkeley, CA. 94270, USA.

¹Adscripción actual: Instituto de Ecología, A.C., Centro Regional de Bajío, Red de Biodiversidad y Sistemática, Av. Lázaro Cárdenas 253, 61600, Pátzcuaro, Michoacán, México.

² Autor para la correspondencia: eduardo.ruiz@inecol.edu.mx

ABSTRACT

Based on recent systematic studies of the genus Otatea, that included an extensive taxonomic investigation of herbaria specimens, and recent fieldwork in the Mexican state of Querétaro, a new Otatea species, O. ramirezii, is here described and illustrated. The new species is endemic to the Sierra Gorda in Querétaro, Mexico. It is compared with Otatea acuminata, O. carrilloi and O. glauca, from which it can be separated by the presence of only one (rarely two) branches per node, erect culm leaf blades, and the absence of oral setae both in culm and foliage leaves.

Key words: endemic Guaduinae, Mexico, Otatea, Poaceae, Querétaro, Sierra Gorda, woody bamboo.

RESUMEN

Basado en un estudio previo sobre sistemática del género Otatea, el cual incluye una amplia revisión de ejemplares de herbario y también en recientes colecciones botánicas realizadas en el estado de Querétaro, se describe e ilustra una nueva especie de Otatea, O. ramirezii. El nuevo taxon es endémico de la sierra Gorda en Querétaro. Se compara con Otatea acuminata, O. carrilloi y O. glauca, de las cuales se diferencia por desarrollar una sola rama por nudo (rara vez dos), láminas de las hoja caulinar erectas y ausencia de setas orales en hojas caulinares y hojas foliares.

palabras clave: bambú leñoso, Guaduinae endémica, México, Otatea, Poaceae, Querétaro, Sierra Gorda.

Otatea (McClure & E. W. Sm) C. Calderón & Soderstr., an American woody bamboo genus of the subtribe Guaduinae, comprises seven species with a geographical distributions restricted to Mexico, El Salvador, Honduras and Colombia and with six species endemic to Mexico (Guzmán et al., 1984; Judziewicz et al., 1999; Londoño and Clark, 1998; Ruiz–Sanchez et al., 2008; Ruiz–Sanchez and Sosa, 2010; Ruiz–Sanchez et al., 2011a).

Previous phylogenetic studies based on morphological and molecular data support the monophyly of Otatea and its sister relationship with the Mesoamerican bamboo genus Olmeca (Ruiz–Sanchez et al., 2008; Ruiz–Sanchez et al., 2011b). Two morphological synapomorphies have been identified for Otatea: 1) branch complements with three subequal and ascending branches and 2) spikelets with pubescent lemmas (Ruiz–Sanchez et al., 2008). However, two recently described species of Otatea (O. reynosoana and O. transvolcanica) mostly have only one or two branches per node. Sometimes three branches occur with the second and third branches smaller in diameter than the central or primary branch (Ruiz–Sanchez et al., 2011a). Like most bamboos, Otatea is monocarpic with mass flowering in cycles that, according to herbarium records, occur in 8–30 year cycles (Guzmán et al., 1984; Judziewicz et al., 1999; Ruiz–Sanchez et al., 2011a); populations usually flower for two or three years consecutively and die (Ruiz–Sanchez et al., 2011a). due to the long intervals between flowering times, a few species have been described based only on vegetative features, including O. carrilloi and O. transvolcanica (Ruiz–Sanchez et al., 2011a).

A new Otatea species from Sierra Gorda of Querétaro with only one (rarely two) branches per node, erect culm leaf blades, and the absence of oral setae both in culm and foliage leaves is described and illustrated in this paper. Also, a key to the eight species of Otatea is presented.

Otatea ramirezii Ruiz–Sanchez sp. nov. fig. 1.

Culmi 2 –3 m alti, 0.8–1–7 cm diam, erecti. Folia culmorum 12–17 cm longa; vaginae 10–12 cm longae, laminae 1.8–4.5 cm longae, erectae, triangulares, abaxialiter glabrescentes. Vaginarum caulinarium setae orales desunt. ramus unus raro duo per nodum. secundarius et tertiarius nodus unum ramum ferens. primarius ramus 33–48 cm longus. Folia ramorum 3–7 per complementum, vaginae glabrae; laminae 6.5–12.5 cm longae, 0.4–1.2 cm latae, lineares vel lineari–lanceolatae. ad 30 mm longae, foliorum frondosarum setae orales desunt.

Rhizomes with necks 5–15 cm long. Culms 2–3 m tall, 0.8–1.7 cm in basal diameter, erect; internodes 12–16 cm long, terete, glabrous, green when young and brown–yellow when old, hollow, the walls 3–5 mm thick, the lacuna occupying <50% of the total diameter. culm leaves 12–17 cm long, non–overlapping, deciduous; sheaths 10–12 cm long, 3.5–5 cm wide at the base, the leaf blades 1.8–4.5 cm long, triangular, abaxially and adaxially glabrous, the margins ciliate when young, glabrous when old; inner ligule a coriaceous rim 0.5–1 mm long, irregular, ciliate; oral setae absent; fimbriae at the apex of the sheath on both sides of the blade, 1–3 mm long, ca. 0.05 mm wide, terete, free, curly; blades 1.8–4.5 cm long, triangular, erect, persistent, shorter than the sheaths, glabrous on both sides, margin glabrous, apex attenuate–subulate. Branching intravaginal; one main branch per node, if two then the central 3–4 times wider than the lateral, sometimes both branches are subequal and these are diverging from each other and rebranching, 33–48 cm long, diverging from the main culm at 45–60°, with only one branch in the second and third order of branching; supranodal ridge pronounced; nodal line horizontal. Foliage leaves 3–5(–7) per complement, when young 5–7 per complement; sheaths glabrous, rounded on the back; oral setae absent; fimbriate at shoulders sheath summit, the fimbriae 1–2 mm long, ca. 0.05 mm in diameter, terete, free, curly; outer ligule an irregular glabrous rim up to 0.1 mm long; inner ligule 0.3–0.5 mm long, truncate, ciliate; pseudopetioles ca. 1 mm long, brownish, pulvinate at the base; blades (6.5)811(12.5) cm long, 0.4–0.8(1.2) cm wide, linear to linear–lanceolate, green adaxially and glabrous abaxially, with a patch of white cilia at the base extending along one side of the midrib for 2–3 mm, the base attenuate, the apex attenuate–subulate, the margins weakly serrulate. Synflorescences not seen.

Habitat and distribution. Apparently, Otatea ramirezii represents a narrow endemic of the southernmost part of the Sierra Gorda in Querétaro, where it forms large populations inhabiting tropical dry forests and their ecotone with oak forests on hillsides composed of calcareous rocks at elevations between 1200 and 1600 m.

On the basis of morphology, Otatea ramirezii morphologically resembles O. acuminata, O. carrilloi and O. glauca. All four are similar in habit with culms that are erect or arching apically and their foliage leaves that are similar in size and form. However, the latter three species develop three subequal ascending branches per node, whereas O. ramirezii develops mostly only one branch per node (Table 1). In some cases, two branches per node are present, but the second one is noticeably narrower than the main branch and it develops later. Additionally, O. ramirezii lacks oral setae in culm and foliage leaves and has erect culm leaf blades. Otatea carrilloi and O. glauca have oral setae in both culm and foliage leaves and their culm leaf blades are reflexed. Alternatively most of the populations in Otatea acuminata have oral setae in the culm leaves but they are absent in the foliage leaves and its culm leaf blades are erect (table 1). Otatea carrilloi and O. glauca are known from a single population each. Both are endemic to chiapas. Otatea acuminata has the widest geographical distribution in Mexico, including two populations near O. ramirezii, one in Querétaro only 22 km to northwest of O. ramirezii on the other side of the sierra Gorda and another one 53 km to the southeast of O. ramirezii in the Barranca of tolantongo, Hidalgo. the populations of Otatea acuminata in Querétaro and Hidalgo grow in calcareous soils and plants from both of these populations develop three subequal ascending branches per node.

Etymology. The specific epithet honors the memory of Raymundo Ramírez Delgadillo (1968–2011), professor from the Universidad de Guadalajara, Mexico, whom I most owe my interest in systematic botany.

ACKNOELEDGMENTS

The author is particularly grateful to Arturo de nova for his invitation to collect Fouqueria species in the locality where the new Otatea species grows. Special thanks are given to Pablo Carrillo Reyes and Heather driscoll for improving the manuscript with their comments and to Flor Rodríguez Gómez for all her support. I also thank three anonymous reviewers whose suggestions greatly improved the manuscript. The illustration is done by David Jimeno Sevilla. Special memory thanks go to Raymundo Ramírez, a great botanist person.

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