Yucca muscipula (Asparagaceae, Agavoideae), a new species from central Mexico Author Ayala-Hernández, María M. 0000-0003-4036-0820 Universidad Nacional Autónoma de México, Facultad de Estudios Superiores Zaragoza, Unidad de Investigación en Sistemática Vegetal y Suelo, Batalla 5 de mayo s / n, Ejército de Oriente, Ciudad de México, 09230, México. & airamagay @ yahoo. com. mx; https: // orcid. org / 0000 - 0003 - 4036 - 0820 airamagay@yahoo.com.mx Author Ríos-Gómez, Ramiro 0000-0002-3466-3887 Universidad Nacional Autónoma de México, Facultad de Estudios Superiores Zaragoza, Unidad de Investigación en Sistemática Vegetal y Suelo, Batalla 5 de mayo s / n, Ejército de Oriente, Ciudad de México, 09230, México. & riosarana 44 @ gmail. com; https: // orcid. org / 0000 - 0002 - 3466 - 3887 riosarana44@gmail.com Author Solano, Eloy 0000-0001-7742-2584 Universidad Nacional Autónoma de México, Facultad de Estudios Superiores Zaragoza, Unidad de Investigación en Sistemática Vegetal y Suelo, Batalla 5 de mayo s / n, Ejército de Oriente, Ciudad de México, 09230, México. & solacael @ yahoo. com. mx; https: // orcid. org / 0000 - 0001 - 7742 - 2584 solacael@yahoo.com.mx Author Mendoza, Abisaí García- 0000-0002-0284-5117 Universidad Nacional Autónoma de México, Instituto de Biología, Jardín Botánico, Tercer circuito exterior de Ciudad Universitaria, Coyoacán, Ciudad de México, 04510, México. & abisai @ ib. unam. mx; https: // orcid. org / 0000 - 0002 - 0284 - 5117 abisai@ib.unam.mx text Phytotaxa 2022 2022-04-12 543 2 103 112 http://dx.doi.org/10.11646/phytotaxa.543.2.1 journal article 56038 10.11646/phytotaxa.543.2.1 fb4015de-a45b-484e-a274-11d13419040f 1179-3163 6450729 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 . TABLE 1. Morphological differences, geographic distribution, phenology and habitat of Yucca muscipula and Y. mixtecana and Y. filifera . Data of Y. mixtecana are from García-Mendoza (1998 , 2011 ). Data of Y. filifera are from Matuda & Piña (1980) , Rentería (2000) , and Galván (2005) .

Character	Yucca muscipula	Y . mixtecana	Y. filifera
Stem	2–4 m, simple	2.5–5 m, simple or branched	Up to10 m, simple or branched, mostly in old plants
Persistence of dry leaves on the stem	Deciduous in the basal portion, and persistent in the distal half in individuals after the first flowering	Deciduous	Persistent
Leaves margin	Glaucous Filiferous, recurved filaments	Glaucous Entire, rarely filiferous, straight filaments	No glaucous Filiferous, recurved filaments
Papillae	Present	Absent	Absent
Inflorescence	Panicle pendulous, 80–110 cm, glabrous	Panicle erect, 50–80 cm, puberulent	Panicle pendulous, until 150 cm, glabrous, peduncle and pedicels rarely pilose
Flowers	Campanulate, pendulous	Campanulate, pendulous	Extended, pendulous
Tepals	3.8–5.0 × 1.0–1.5 cm	2–3 × 0.4 –0.7 (1.0) cm	3.8–5.2 × 0.7–2.5 cm
Filaments	1.8–2.8 cm long	1.0–2.0 cm long	1.0–1.5 cm long
Papillae	Across the entire surface	In two marginal lines	Across the entire surface
Gynoecium	2.1–2.9 cm long	1.5–2.0 (–3.0) cm long	2.3–2.5 cm long
Carpelar depressions	Little deep	Very deep	Very deep
Fruit	8.5–11.7 × 2.5–3.2 cm	3.0–8.0 × 2.0–2.5 cm	5.0–8.8 × 2.7–3.3 cm
Seeds	8.0–10.0 × 6.0–7.0 mm	5.0–7.0 × 5.0–6.0 mm	6.0–8.0 × 2.0–5.0 mm
shape	Prismatic	Prismatic	Oblong
Geographical distribution	Barranca de Metztitlán, Hidalgo, Mexico	Valle de Tehuacán-Cuicatlán, Puebla and Oaxaca, Mexico	Broad range, mainly in the Eastern portion of the Mexican Plateau and the transition with the Sierra Madre Oriental and the Transmexican Volcanic Belt
Elevation	1294–1350 m	1370–2200 m	500–2400 m
Phenology	Flowers from April to July, fruits from June to August	Flowers from March to May, fruits from July to September	Flowers from March to August, fruits from June to Octubre
Habitat	Xeric scrubland, thorn forest	Xeric scrubland, deciduous tropical forest	Xeric scrubland

FIGURE 1. Yucca muscipula : a) complete plant, b) leaf, c) apex leaf, d) branch inflorescence, e) flower, f) dissected flower, g) stamen, h) gynoecium, i) fruit, j) seeds. Illustration by Albino Luna Sánchez. FIGURE 2. Yucca muscipula : a) plants, b) leaves with margin filaments, c) plants with inflorescence, d) flowers, e) fruits. Y. mixtecana : f) plants, g) inflorescence, h) flowers, i) fruits (photos: R. Ríos-Gómez, a, c and e; E. Solano, b and d; A. García-Mendoza, f–i). 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 ) . FIGURE 3. Geographic distribution of Yucca muscipula in Hidalgo, México. 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.