Opuntia streptacantha Lemaire (1839: 62) Neotype (designated by Scheinvar et al. 2010: 283): — MEXICO. Hidalgo, Zempoala, east of Téllez basis of El Cerrito, 23 March 1973, Scheinvar & Ahuatzin 2024 (MEXU!). = Opuntia streptacantha subsp. aguirriana Scheinvar & Rodríguez (2003: 304). Description:— Plant 2.0–3.0 m high tree (Fig. 11A). Defined trunk of 60 cm in diameter, grayish scaly bark with black shades (Fig. 11B). Glabrous epidermis (Fig. 14C). Oval cladodes, 32–40 cm long × 23–35 cm wide and 2–3 cm thick, green in color, covered with a very light layer of wax (Fig. 12A). Areolas arranged in 10–11 series, 3 cm spacing between series, 2.1 cm spaing between elliptical areolas of 0.4 × 0.3 cm, short black trichomes (Fig. 12B). Very small and scarce yellow gloquids, arranged at the top of the areola. 0–8 white spines with gray and black tones, flexible, acicular, some slightly twisted, adpressed and diffuse, very few erect, unequal of 0.2–2.2 cm long, yellowish apex, in the lower part of the cladode some areolas do not have spines (Fig. 12C). Juvenile cladodes with prominent tubers, areolas with short brown to black trichomes, some white bristel hairs with reddish tones, subulate, erect, green leaves, with uncinate slightly reddish apex, white spines with reddish apex (Fig. 11C). Acute flower buds, green perianth segments with reddish acuminate apex, elliptic pericarpel, slightly raised tubers, areolas with short black trichomes, brown glochids and brown bristle areolas (Fig. 12D and 12E). Yellow flowers (Fig. 12F), 5.5–6.1 cm long, elliptical pericarp, ca. 3.2 × 2.0 cm, areolas arranged in 4–5 series, 0.62 cm spacing between them, outer segments of perianth with spatulate shape, rounded apex, smooth yellow edges, with medium greenish striation, reddish apex, oblanceolated inner segments, emarginated apex, yellow, smooth upper edges, stamens 1/3 of the length of the perianth, yellow filaments, yellow anthers, white, cuneiform style, ca. 2.3 cm long, usually nine green papillary lobes of stigma, ca. 0.4 cm long, with medium white striation (Fig. 13B). Red elliptical to obovate fruits (Fig. 13C), 4–6 cm long, slightly sunken striated floral scar, circular to elliptical large areolas (Fig. 13E), arranged in 6–7 series, 1.1 cm spacing from each other and 1 cm between series, long black trichomes, some spines, yellow glochids, red juicy and sweet funicles (Fig. 13D). Discoid seed with irregular lateral aril, lateral thread-micropillar region, microphile and funiculus included (Fig. 13F). Micromorphology:— Thornswith lignified epidermal cells 13.38 ± 1.90 × 3.59 ± 1.3 μm in the distal part (Fig. 14B), 114.01 ± 1.10 × 12.79 ± 1.20 μm, non-continuous epidermal cells with fissures between cells and smooth texture, in the middle part (Fig. 14A). Glabrous epidermis, irregular epidermal cells (Fig. 14C) and cyclocytic stomas (Fig. 14D). Polyhedron-shaped pollen grain, pantoaperturate (Fig. 14E), 114.64 ± 1.90 μm in diameter, 9219.1 μm ² in area, 13.89 ± 2.10 μm distance between each distal opening (pores), with a diameter of 21.49 ± 1.50 μm, 22–24 pores with walls of 2.43 ± 0.04 μm width and wart (Fig. 14F). Vernacular names:— Nopal cardón, Tuna cardona and Nopal hartón (see e.g., Bravo-Hollis 1978, Scheinvar 2004). Phenology:— Opuntia streptacantha blooms from March–April, whereas fruiting time if June–July. Habitat and distribution:— Endemic to Mexico, it is known in the states of Aguascalientes, Chihuahua, Ciudad de México, Coahuila, Durango, Guanajuato, Hidalgo, Jalisco, México, Michoacán, Nuevo León, Oaxaca, Puebla, Querétaro, San Luis Potosí, Tlaxcala, Veracruz and Zacatecas (see e.g., Arias et al. 1997, Guzmán et al. 2003, Scheinvar 2004, Scheinvar et al. 2010, Arias et al. 2012, Hernández et al. 2014) (Fig. 2). It grows in xerophytic scrub and tropical deciduous forest (Rzedowski 1978).

Published as part of Martínez-González, César Ramiro, Gallegos-Vázquez, Clemente, Mascorro- Gallardo, José O. & Barrientos-Priego, Alejandro F., 2022, Molecular and morphological notes on Opuntia ser. Streptacanthae (Cactaceae), pp. 1-28 in Phytotaxa 576 (1) on pages 12-19, DOI: 10.11646/phytotaxa.576.1.1, http://zenodo.org/record/7440876