Yucca muscipula M. Ayala-Hern., Ríos-Gómez, E. Solano & A. García-Mend., sp. nov. (Figs. 1, 2).

Yucca muscipula is morphologically similar to Yucca mixtecana and to a few branched individuals of Y. filifera, from which it differs in the unbranched stem, and longer leaves that are persistent on the distal portion of the stem after the first flowering. Its tepals are 4–5 cm long, with the outer ones being 1.0– 1.5 cm wide and the inner ones being 1.4–2.0 cm wide. Its filaments are 1.8–2.8 cm long and papillose, while its ovary is 1.8–2.3 cm long and 3.3–6.3 mm in diameter; the fruit and seeds seeds are larger than those of Y. filifera.

Type:— MEXICO. Hidalgo: Municipality Metztitlán, highway San Juan Metztitlán-Zoquizoquipan, aproximately 2.6 km northeast from San Juan Metztitlán, xeric scrubland, 1320 m, 26 Jun 2021 (fl), R. Ríos-Gómez et al. 2046 (Holotype: MEXU!; Isotypes: CIIDIR!, DES!, FEZA!, UAMIZ!).

Plants arborescent, iteroparous, 2–4 m tall, rarely surculose. Stem simple, cylindrical, dry leaves persistent in the distal portion of individuals after the first flowering. Rosette leaves at the apex of the stems, linear, 63.5–82.6 cm long, 1.6–2.5 cm wide in the middle portion, ascending to appressed, coriaceous, glaucous, papillate on both surfaces, margin entire, filiferous, the filaments recurved, gray; terminal spine 0.6–1.0 cm long, brown, ribbed, conical, base bicolored, basally white, distal portion reddish-brown. Inflorescence paniculate, pendulous, 80–110 cm long, rachis white-greenish, once branched, branches 10–17 cm long, glabrous; bracts lanceolate, 7–14 cm long, 1–2 cm wide in the middle, yellowish-white, papyraceous, base reddish-brown, truncated, margin entire, apex acuminate. Flowers campanulate, whitish, greenish-white or yellowish-white, pedicels 1.0– 1.8 cm long, ascending, rarely arched, terete, glabrous; external tepals 3.9–5.0 cm long, 1.0– 1.5 cm wide, ovate-elliptical, base attenuate, margin entire, apex acute, the internal ones similar to the external ones but wider, 1.4–2 cm wide; filaments flattened, the apical portion thickened, diffuse, papillose; anthers yellow, 1.5–2.3 mm long, sagittate, extrose; ovary 1.8–2.5 cm long, 3.3–6.3 mm diameter, cylindrical, with slightly sunken carpels, septa prominent, green, style short; stigma 3-lobed, lobes 3.5–5.0 mm long, retuse, white, with scattered papillae. Fruits baccate, 8.0– 11.7 cm long, 2.5–3.2 cm diameter, cylindrical, pendulous, arched above the middle, crowned by the remains of the dried perianth, fleshy, indehiscent. Seeds 0.8–1.0 cm long, prismatic, slightly rough, black, dull; endosperm ruminated.

Geographical distribution and habitat:—Endemic to the municipality of Metztitlán, Hidalgo, Mexico; in xeric scrublands and thorny forests with Acacia farnesiana (L.) Willdenow (1806: 1083), Agave striata Zuccarini (1833: 678), A. xylonacantha Salm-Reifferscheid-Dyck (1859: 92), Bursera Jacquin ex Linnaeus (1762: 471), Cephalocereus senilis (Haw.) Pfeiffer (1838: 142), Cnidoscolus multilobus (Pax) Johnston (1923: 86), Fouquieria splendens Engelmann (1848: 98), Jatropha dioica Sessé (1794: 4), Mimosa Linnaeus (1753: 516), Myrtillocactus geometrizans Console (1897: 10), Prosopis laevigata (Humb. & Bonpl. ex Willd.) Johnston (1962: 78) and Yucca filifera Chabaud (1876: 432); on lithic leptosols and regosols at elevation 1294–1350 m (Fig. 3).

Phenology: — Yucca muscipula flowers from April to July and fruits from June to August.

Additional specimens examined (paratypes): — MEXICO. Hidalgo: Metztitlán Municipality, La Paila de Anáhuac, 1322 m, 17 April 2021, R. Ríos-Gómez et al. 2038 (FEZA); San Juan Metztitlán, 1294 m, 26 June 2021, R. Ríos-Gómez et al. 2047 (FEZA); Banks of the Pía Sapa stream, 3 km from San Juan Metztitlán, 1350 m, 6 July 2021, R. Ríos-Gómez 2048 et al. (FEZA).

Etymology: —The epithet is derived from the common name by which this plant is known in the type locality, “mousetrap palm” (mousetrap = muscipula).

Uses: —The whole plant is used to establish living fences and the flowers are edible.

Conservation status: — Yucca muscipula is Critically Endangered according to IUCN criterion B1, since it covers an extent of occurrence (EOO) of <100 km 2 and Endangered based on criterion B2, because the area of occupancy (AOO) covers <500 km 2. This species is restricted to four locations in the Barranca de Metztitlán Biosphere Reserve and its populations occupy 1.7% of its surface, which is 96,042 ha. In addition, it forms localized populations with few individuals in habitats close to rural human settlements and roads.