Culm anatomy of the genus Otatea (Poaceae, Bambusoideae, Bambuseae, Guaduinae) as a contribution to Mexican species identification Author García-Martínez, Miguel A. Doctorado en Ciencias en Biosistemática, Ecología y Manejo de Recursos Naturales y Agrícolas, Universidad de Guadalajara, Camino Ing. Ramón Padilla Sánchez 2000, Nextipac, Zapopan, Jalisco, 45200, Mexico. & Laboratorio Nacional de Identificación y Caracterización Vegetal (LaniVeg), Instituto de Botánica, Universidad de Guadalajara, Camino Ing. Ramón Padilla Sánchez 2000, Nextipac, Zapopan, Jalisco, 45200, Mexico. Author Terrazas, Teresa 0000-0001-7749-5126 Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, Coyoacán 04510, Mexico City, Mexico. Departamento de Botánica y Zoología, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Camino Ing. Ramón Padilla Sánchez 2000, Nextipac, Zapopan, Jalisco, 45200, Mexico. & tterrazas @ ib. unam. mx; https: // orcid. org / 0000 - 0001 - 7749 - 5126 tterrazas@ib.unam.mx Author Sánchez, Daniel Investigador por México, Consejo Nacional de Humanidades Ciencias y Tecnologías (CONAHCYT), Laboratorio Nacional de Identificación y Caracterización Vegetal, Departamento Botánica y Zoología, Universidad de Guadalajara, Camino Ing. Ramón Padilla Sánchez 2000, Nextipac, Zapopan, Jalisco, 45200, Mexico. Author Reyes, Pablo Carrillo- 0000-0001-9278-0208 pablo. creyes @ academicos. udg. mx; https: // orcid. org / 0000 - 0001 - 9278 - 0208 pablo.creyes@academicos.udg.mx Author Ruiz-Sanchez, Eduardo Laboratorio Nacional de Identificación y Caracterización Vegetal (LaniVeg), Instituto de Botánica, Universidad de Guadalajara, Camino Ing. Ramón Padilla Sánchez 2000, Nextipac, Zapopan, Jalisco, 45200, Mexico. text Phytotaxa 2023 2023-08-22 609 2 75 102 http://dx.doi.org/10.11646/phytotaxa.609.2.1 journal article 10.11646/phytotaxa.609.2.1 1179-3163 8272241 Otatea acuminata OAX ( Fig. 4 ) Material examined: — Oaxaca : Tepelmeme Villa de Morelos , Km 107, Puebla-Oaxaca toll road, Puente Los Otates , 18°1’53.2”N , 97°20’58.7”W , 1961 m , 1 February 2020 , E . Ruiz-Sanchez & M . A . García-Martínez 644 ( IBUG !) . FIGURE 4. Culm cross section of Otatea acuminata OAX. A . Cross section general view. B . Parenchymatous ground tissue with sporadic conical silica bodies. C . Epidermis and cortex. D . Peripheral vascular bundle. E . Transitional vascular bundle. F . Central vascular bundle. Abbreviations: co , cortex; ep , epidermis; fs , fiber sheath; mx , metaxylem; pa , parenchyma; ph , phloem; px , protoxylem; sc , sclerenchyma; si , silica bodies. Culm anatomy description: —Culm solid. Epidermis with a layer of axially elongated lignified cells, 12 µm length, with frequent silica bodies on top ( Fig. 4C ). Cortex with one layer of narrow thick-walled rounded cells followed by 3–4 layers of wider thin-walled rounded cells (4–5 layers in total, 43 µm wide), the inner ones only with primary walls, chloroplasts and dark staining deposits in some cells ( Fig. 4C ). Vascular bundles in 11–12 alternating cycles ( Fig. 4A ). Peripheral, transitional, and central vascular bundles surrounded by a lignified sclerenchyma sheath defining their contour ( Figs. 4D–F ). Cell wall of fiber sheath weakly lignified. Ovate central vascular bundles, 426 × 392 μm; two round shaped metaxylem vessels, 93 × 89 μm, phloem with sieve tubes and companion cells located between two metaxylem vessels on the upper level, 93 × 136 µm; sieve tubes 17 × 21 µm ( Fig. 4F ). Scarce amorphous silica bodies embedded along the periphery of vascular bundles occupying cellular spaces covering a mean area of 49 µm 2 . Sporadic conical silica bodies across the ground tissue occupying intercellular spaces covering a mean area of 17 µm 2 ( Fig. 4B ).