Otatea fimbriata (Fig. 7)

Material examined: — MEXICO. Chiapas: Ixtapa, Km 20 toll road Tuxtla Gutiérrez-San Cristóbal de las Casas, 16°41’53.31”N, 92°51’48.14”W, 1300 m, 15 February 2022, E . Ruiz-Sanchez et al. 732 (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. 7B). Cortex with 1–2 layers of narrow thick-walled rounded cells followed by 4–5 layers of wider and thinner-walled rounded cells (6–7 layers in total, 73 µm length; Fig. 7B). Vascular bundles in 11–12 alternating cycles (Fig. 7A). Peripheral, transitional, and central vascular bundles surrounded by a sclerenchyma sheath defining their contour (Figs. 7C–E). Elliptical central vascular bundles, 556 × 615 μm; two round shaped metaxylem vessels, 119 × 117 μm; phloem with sieve tubes and companion cells located between two metaxylem vessels on the upper level, 115 × 195 µm; sieve tubes 20 × 27 µm (Fig. 7E). Scarce amorphous silica bodies embedded along the periphery of vascular bundles occupying cellular spaces covering a mean area of 127 µm 2. Frequent conical silica bodies across the ground tissue occupying intercellular spaces covering a mean area of 20 µm 2.