Otatea glauca (Fig. 8)

Material examined: — MEXICO. Chiapas: Motozintla, Km 37 of the Huixtla-Motozintla highway, 15°19’46.58”N, 92°19’25.72”W, 1141 m, 14 February 2022, E . Ruiz-Sanchez et al. 726 (IBUG!) .

Culm anatomy description: —Culm hollow, the lacuna occupying> 50% of the total diameter. Epidermis with a layer of axially elongated lignified cells, 12 µm length, with frequent rectangular silica bodies on top (Fig. 8C). Cortex with 2 layers of narrow thick-walled cells followed by 2–3 layers of wider, thinner-walled cells (in total, 4–5 layers, 52 µm length; Fig. 8C). Vascular bundles in 8–9 alternating cycles (Fig. 8A). Peripheral, transitional, and central vascular bundles surrounded by a lignified sclerenchyma sheath defining their contour (Figs. 8D–F). Cell wall of fiber sheath weakly lignified. Oval central vascular bundles, 462 × 362 μm; two round shaped metaxylem vessels, 89 × 92 μm; phloem with sieve tubes and companion cells located between two metaxylem vessels on the upper level, 82 × 104 µm; sieve tubes 18 × 21 µm (Fig. 8F). Scarce amorphous silica bodies embedded along the periphery of vascular bundles occupying cellular spaces covering a mean area of 187 µm 2 (Fig. 8B). Sporadic conical silica bodies across the ground tissue occupying intercellular spaces covering a mean area of 6 µm 2.