Taxonomic review of Ceratozamia (Zamiaceae) in the Sierra Madre Oriental, Mexico Martinez-Dominguez, Lili Nicolalde-Morejon, Fernando Vergara-Silva, Francisco Stevenson, Dennis Wm. PhytoKeys 2018 2018-06-21 100 91 124 EF371461-7246-55E5-9E3D-CC50DE0B85E8 Medellin-Leal. Brittonia 15: 175 - 176. 1963. Medellín-Leal. Brittonia 15: 175 – 176. 1963. Cycadopsida Zamiaceae Ceratozamia CoL Plantae Ceratozamia zaragozae Cycadales 21 112 Tracheophyta species zaragozae    Type.   MEXICO. San Luis Potosi:  RioVerde, 22 Jul. 1962.  F. Medellin-Leal1452( holotype: SLPM; isotypes: ENCB, MICH, US).  Description.  Stemsemihypogeous, erect, 10-20 cm in length, 10-15 cm in diameter. Cataphyllspersistent, densely tomentose at emergence, reddish-brown and partially tomentose at maturity, triangular, apex acuminate, 1.8-2.5 x1-2 cm at base. Leaves3-27, ascending, 95-202 cm, reddish-brown at emergence with whitish-grey pubescence, glabrous at maturity. Petioleterete, twisted, 11-36 cm, unarmed, green in adult leaves. Rachisterete, twisted, 40-77 cm, unarmed, green in adult leaves. Leaflets25-46, linear, mostly planar, basally falcate, membranaceous, strongly caniculate, opposite to subopposite, plane, green, adaxial and abaxial side glabrous, acute apex, symmetric apex, attenuate at base, with conspicuous and light green veins; median leaflets 17-31.5 x0.4-0.7 cm, 0.8-2.3 cm between leaflets; articulations yellow, 0.2-0.3 cm wide. Polliniferous strobilussolitary, cylindrical, erect, 15-19 cm in length, 2-3.5 cm in diameter, greenish with reddish-brown pubescence at emergence, reddish-brown at maturity; peduncle tomentose, reddish-brown to brown, 5-8 cm in length, 1.5-1.8 cm in diameter; microsporophylls 0.8-1.2 x0.3-0.6 cm, non-recurved distal face. Ovuliferous strobilussolitary, cylindrical, erect, 8.2-12 cm in length, 5.8-7 cm in diameter, green with scarcely reddish-brown trichomes at emergence, dark green at maturity, acute apex; peduncle tomentose, brown, 6-9 cm in length, 0.9-1.2 cm in diameter; megasporophylls 24-49, 2.2-3.7 x2-2.6 cm, truncate distal face, obtuse angle between horns. Seedsovoid, sarcotesta light brown at maturity, 2-2.8 cm in length, 1.8-2 cm in diameter.  Distribution and habitat. Endemic to Mexico in a small mountain range in South Central San Luis Potosiat 1,500-1,800 m elevation (Fig. 9). The vegetation type of the habitat is pine-oak forest.   Figure 9.Distribution map of  Ceratozamia sabatoi,  C. latifolia,  C. zaragozae,  C. kuesteriana,  C. hildae,  C. fuscoviridisand  C. chamberlainii.  Etymology. The specific epithet is refers to General Ignacio Zaragoza, a hero of the Battle of Puebla (May 1862) against the French Army.  Distinguishing features. This species is distinguished by having petiole and rachis unarmed and twisted. Leaflets are lanceolate, mostly planar, not basally falcate, membranaceous and caniculate, with symmetric apex.  Specimens examined.  MEXICO.  San Luis Potosi: RioVerde, A. G. Mendoza & L. Vargas 1389(MEXU), A. P. Vovides 435(XAL), E. Molseed 34(MEXU), F. Nicolalde-Morejonet al. 2307-2319(CIB), L. Martinez-Dominguezet al. 792-808(CIB), T. Walters et al. TW-2001-07(MEXU, XAL).   Figure 10.  Ceratozamia latifolia.   Figure 11.  Ceratozamia mexicana. AAdult plant in habit BLeaf at emergence CDetail of pollen strobili DMicrosporophyll EMegasporophyll FDetail of ovulate strobili GSeeds. 1962-07-22 F. Medellin-Leal MEXICO Rio Verde 1 San Luis Potosi holotype