Otatea rzedowskiorum (Fig. 11)

Material examined: — MEXICO. Chiapas: Ocozocoautla, El Aguacero waterfall, 16°45’35.34”N, 93°31’29.32”W, 535 m, 15 February 2022, E . Ruiz-Sanchez et al. 731 (IBUG!).

Culm anatomy description: —Culm solid. Epidermis with a layer of axially elongated lignified cells, 9 µm length, with occasional rectangular silica bodies on top (Fig. 11C). Cortex with a layer of thick-walled axially elongated cells followed by 2–3 layers of wider thinner-walled rounded cells (in total, 3–4 layers, 23 µm length; Fig. 11C). Vascular bundles in 5–6 alternating cycles (Fig. 11A). Peripheral, transitional, and central vascular bundles surrounded by a sclerenchyma sheath defining their contour (Figs. 11D–F). Central vascular bundles broadly depressed, 180 × 260 µm; two round shaped metaxylem vessels, 63 × 64 µm; phloem with sieve tubes and companion cells located between two metaxylem vessels on the upper level, 49 × 60 µm, sieve tubes 15 × 14 µm (Fig. 11F). Sporadic conical silica bodies across the ground tissue occupying intercellular spaces covering a mean area of 8 µm 2 (Fig. 11B). Abundant starch grains in the ground cells (Fig. 11B).