Systematic Botany (2013), 38(2): pp. 1–12 © Copyright 2013 by the American Society of Plant Taxonomists DOI 10.1600/036364413X666642 Four New Species of Agave (Agavaceae) of the Marmoratae Group J. Antonio Va ´zquez-Garcı´a, 1,4 Miguel A ´ . Mun ˜ iz-Castro, 1 Eduardo Sahagu ´n-Godı´nez, 2 Miguel de J. Cha ´zaro-Basa ´n ˜ ez, 3 Ernesto De Castro-Arce, 1 Gregorio Nieves-Herna ´ndez, 1 and Jesu ´ s Padilla-Lepe 1 1 Herbario IBUG, Instituto de Bota ´nica, Departamento de Bota ´nica y Zoologı ´a, Centro Universitario de Ciencias Biolo ´ gicas y Agropecuarias, Universidad de Guadalajara Km 15.5 carr. Guadalajara a Nogales, Las Agujas, Nextipac, Zapopan, 45110, Jalisco, Me ´xico. 2 Herbario y Jardı ´n Bota ´nico GUADA, Universidad Auto ´ noma de Guadalajara Av. Patria 1201, Apdo. Postal 1-440, Guadalajara, 44100, Jalisco, Me ´xico; e-mail: cladium@yahoo.com.mx. 3 Departamento de Geografı ´a y Ordenacio ´ n Territorial, Universidad de Guadalajara-CUCSH, Guadalajara, Jalisco, C.P. 45101, Me ´xico; e-mail: pachy8@prodigy.net.mx. 4 Author for correspondence (jvazquez@cucba.udg.mx) Communicating Editor: Andrew L. Hipp Abstract—We present a re-evaluation of the taxonomic status of Agave gypsophila, for which a narrower circumscription is proposed, and four new species from western Mexico are described and illustrated: Agave abisaii, A. andreae, A. kristenii and A. pablocarrilloi. All four species are narrow endemics occurring on a variety of limestone outcrops and belong to the subgenus Agave and to the Marmoratae species group sensu Berger. They are morphologically related to A. gypsophila s. s. from Guerrero, Mexico, but clearly differ from it in various qualitative and quantitative morphological and ecological characteristics. Resumen—Se presenta una re-evaluacio ´n del estatus taxono ´mico de AGAVE GYPSOPHILA en la cual se propone una circunscripcio ´n ma ´s estrecha, y se describen e ilustran cuatro especies nuevas del occidente de Me ´xico: Agave abisaii, A. andreae, A. kristenii y A. pablocarrilloi. Las cuatro especies son ende ´micas restringidas y se presentan en diferentes afloramientos de roca calca ´rea, pertenecen al subge ´nero Agave y al grupo de especies Marmoratae sensu Berger. Todas tienen relacio ´ n morfolo ´gica con A. gypsophila s.s. de Guerrero, Me ´xico, pero difieren claramente de e ´sta en caracterı ´sticas morfolo ´ gicas y ecolo ´ gicas, tanto cualitativas como cuantitativas. Keywords—Maguey de pen ˜ a, maguey de piedra, Agave abisaii, Agave andreae, Agave gypsophila, Agave kristenii, Agave pablocarrilloi, Western Mexico. The Marmoratae species group (Berger 1915) displays a notable pattern of allopatric speciation, habitat specialization and narrow endemism. The group has heretofore included six species of Agave, all from Mexico: A. zebra Gentry, A. nayaritensis Gentry, A. valenciana Cha ´zaro & A.Va ´zquez, A. gypsophila Gentry, A. marmorata Roezl and A. grijalvensis B. Ullrich (Gentry 1982; Ullrich 1990; Etter and Kristen 2002; Cha ´zaro-Baza ´n ˜ ez et al. 2005; Va ´zquez-Garcı ´a et al. 2007). Martin Kristen, an experienced botanical explorer and gar- dener of succulents based at Atotonilco El Alto, Jalisco, informed us about an Agave population growing on calcar- eous outcrops at Maruata, Michoaca ´n, which may not correspond to A. gypsophila. A close examination of avail- able herbarium specimens, living individuals and descrip- tions traditionally referred to A. gypsophila (e.g. Gentry 1982; McVaugh 1989), unveiled a species complex with a great deal of overlooked and poorly understood morpho- logical variability. We here refer to this species complex as the Gypsophila complex and investigate the question of what the true cir- cumscription of A. gypsophila is. Additional field work in the states of Colima, Guerrero, Jalisco, and Michoaca ´n supplied morphological and ecological data to support a narrower circumscription for A. gypsophila while providing evidence to propose four new species which are formally described below. As a result of this addition, the Marmoratae species group now includes ten species ( F1 Fig. 1). However, the posi- tion of Agave grijalvensis B. Ullrich (syn. A. kewensis Jacobi) remains uncertain, since Gentry (1982) considered it as mem- ber of the Sisalanae group, whereas Ullrich (1990) proposed this species as a part of the Mamoratae group. Taxonomic Treatment The Marmoratae Group circumscription (Berger 1915), as a result of the addition of these four new species, needs to be broadened to include: a) the surculose habit pres- ent in A. abisaii, A. kristenii, and A. pablocarrilloi; b) the numerous leaves feature found in A. andreae; c) the smooth texture of leaves represented by A. abisai, A. andreae and A. gypsophila s. s.; d) the orange colored flowers typical of A. abisai, A. kristenii and A. pablocarrilloi; and e) its more commonly calcareous habitat, now represented in six out of the ten Marmoratae species. Key to the species of the MARMORATAE GROUP 1. Larger mature rosettes usually 1.8–4.1 m in diameter ............................................................................... 2 2. Leaves broadly lanceolate, 20–60 cm wide, rigid, undulate, evidently cross-zoned, teeth 6–12 mm long ................................. 3 3. Rosettes 1.7–2.2 + 2.7–3.3 (–4.1) m; leaves 7–15, 150–230 + 37–46 (–53) cm, dark green; flowers 50–60 (–70) mm long; on volcanic substrate with tropical dry forest or oak woodland ecotones, 900–1250 m; Jalisco .......................... A. valenciana 3. Rosettes 1.2–1.3 + 2 m; leaves 30–50, 100–135 + 20–30 cm, light green; flowers 40–48 mm long; on limestone with xerophytic scrub or oak woodlands, 1550–1900 m; Puebla and Oaxaca ......................................... A. marmorata 2. Leaves narrowly lanceolate to lanceolate, 12–15 cm wide, brittle-flexible, straight to slightly undulate, not evidently cross-zoned, teeth 3–4 mm long ................................................................................. 4 4. Spine 30–45 mm long; flowers 60–74 mm long, ovary 30–40 mm long, anthers at anthesis 26–27 mm long, tepals 18–20 mm long, tube 12–15 mm long; on limestone with tropical dry forest, 400–1,000 m; Chiapas ................ A. grijalvensis 1