Otatea transvolcanica (Fig. 12)

Material examined: — MEXICO. Colima: Comala, dirt road Campo Cuatro to El Terrero, 19°24’05”N, 103°51’39”W, 1709 m, 25 July 2020, J. P . Ortíz-Brunel et al. 831 (IBUG!).

Culm anatomy description: —Culm solid. Epidermis with a layer of axially elongated lignified cells, 12 µm length, with frequent squared to rectangular silica bodies on top (Fig. 14B). Cortex with one layer of narrow thick-walled rounded cells followed by 4–5 layers of wider, thinner-walled rounded cells (6–7 layers in total, 72 µm length; Fig. 14B). Vascular bundles in 10–11 alternating cycles (Fig. 14A). Peripheral, transitional, and central vascular bundles surrounded by a sclerenchyma sheath defining their contour (Figs. 14C–E). Cell wall of fiber sheath weakly lignified. Elliptical central vascular bundles, 468 × 269 μm; two round shaped metaxylem vessels, 77 × 79 μm; phloem with sieve tubes and companion cells located between two metaxylem vessels on the upper level, 101 × 106 µm; sieve tubes 17 × 24 µm (Fig. 14E). Frequent amorphous silica bodies embedded along the periphery of vascular bundles occupying cellular spaces covering a mean area of 54 µm 2.