Ceratozamia mixeorum Chemnick, T.J.Greg. & Salas-Mor., Phytologia 83(1): 47 1998 ( "1997" )

Martinez-Dominguez, Lili, Nicolalde-Morejon, Fernando, Vergara-Silva, Francisco & Stevenson, Dennis Wm., 2022, Monograph of Ceratozamia (Zamiaceae, Cycadales): an endangered genus, PhytoKeys 208, pp. 1-102 : 1

21. Ceratozamia mixeorum Chemnick, T.J.Greg. & Salas-Mor., Phytologia 83(1): 47 1998 ( "1997")

Fig. 7H

Type.

Mexico. Oaxaca: Cercanía a Juquila Mixe , 1,737 m, 21 May 1997. J. Chemnick & T. Gregory 49 (lectotype, designated by Nicolalde-Morejón and Avendaño 2011, pg. 1033: XAL! [XAL0065870]) .

Description.

Stem 30-100 cm long, 18-25 cm in diameter, epigeous, decumbent. Cataphylls 1.8-4.6 × 1.9-4.3 cm wide at the base, persistent, triangular, reddish brown, densely brown tomentose at emergence, partially tomentose at maturity, apex acuminate. Leaves 3-17 (30), 85-246 cm long, descending, light green and glaucous at emergence with light brown trichomes, glabrous at maturity. Petiole 46-132 cm long, terete, linear, green in mature leaves; with 30-50 thin prickles, 0.20-0.38 cm long. Rachis 58-118 cm long, terete, linear, green to greenish in mature leaves, with scarce prickles. Leaflets 19-35 pairs, opposite to subopposite insertion in one plane, lanceolate, abaxially curved, rarely planar, not basally falcate, papyraceous, flat, green with adaxial and abaxial sides glabrous, distal end with entire margins, acuminate and symmetrical at the apex, attenuate at base, with conspicuous and green-light veins; median leaflets 24-39 × 1.9-2.9 cm, 1.7-3.0 cm between leaflets; articulations 0.6-1.0 cm wide, green. Pollen strobili 22-30 cm long, 4.5-7 cm in diameter, generally solitary (1-2), cylindrical, erect, greenish at emergence with reddish trichomes, greenish yellow with reddish brown trichomes at maturity; peduncle 10-15 cm long, 1.2-2.0 cm in diameter, glabrous or with trichomes scarce reddish brown to brown; microsporophylls 1.4-2.4 × 0.7-1.3 cm, obconic with a non-recurved distal face and lobate fertile portion, infertile portion 0.39-0.48 cm long and linear with straight horns 0.30-0.50 cm long, 0.50-0.93 cm and a right angle between the horns. Ovulate strobili 23-32 cm long, 12-16 cm in diameter, solitary, cylindrical, erect, yellowish green with abundant blackish trichomes at emergence, green with brown to blackish trichomes at maturity, apiculate apex; peduncle 12-23.5 cm long, 1.3-2.1 cm in diameter, pendulous, glabrous or with scarce reddish brown trichomes; megasporophylls 60-112, 6-9 orthostichies with 10-14 sporophylls per orthostichy, 2.4-2.8 × 4.0-5.1 cm, with a truncate distal face, horns straight and 0.90-1.1 cm long, 0.92-1.2 cm between horns and a right angle between the horns. Seeds 2.2-3.0 cm long, 1.6-2.0 cm in diameter, ovate, sarcotesta whitish yellow to yellow when immature, light brown at maturity.

Distribution and habitat.

Ceratozamia mixeorum is endemic to the southern portion of Sierra Norte of Oaxaca State (Mexico), along the highlands in the Mixe area (Fig. 21A ), where it occurs in karstic rocks of cloud and oak forests between 1,170 to 2,150 m.

Etymology.

The specific epithet was named in honor of the Mixe people.

Common names.

Mexico. Oaxaca: Carrete ( Chemnick et al. 1998).

Uses.

The pollen strobilus is used as a toy ( Chemnick et al. 1998).

Conservation status.

( IUCN 2021). Ceratozamia mixeorum is listed under criteria A2cd+4cd; B1ab(ii,iii,v) as “Endangered”.

Discussion.

Ceratozamia mixeorum is similar to C. whitelockiana , but has prickles on the rachis of the leaf and a densely prickly petiole (up to 50 prickles), ovulate strobili with long and pendulous pedunclse up to 23.5 cm long. The fertile portion of ovulate strobilus has 6-9 orthostichies and 10-14 sporophylls per orthostichy; in contrast to 4-5 orthostichies and 5-8 sporophylls per orthostichy in C. whitelockiana .

Specimens examined.

Mexico. Oaxaca: Mun. Guevea de Humboldt, 1,300 m, 30 Mar 1991, A. Campos 3614 (MEXU). Mun. San Juan Juquila Mixes, 1,605 m, 7 Apr 1995, E. Torres B. 563 (SERO, XAL); 1,595 m, 25 Sep 2020, F. Nicolalde-Morejón et al. 3368 (CIB); 1,681 m, 25 Sep 2020, F. Nicolalde-Morejón et al. 3369-3371 (CIB); 1,595 m, 25 Sep 2020, L. Martínez-Domínguez et al. 2001, 2002 (CIB); 1,681 m, 25 Sep 2020, L. Martínez-Domínguez et al. 2003 (CIB, MEXU), 2004-2006 (CIB). Mun. San Pedro Ocotepec, 8 Apr 1995, 1,600 m, E. Torres B. et al. 607 (XAL). Mun. Santa María Guienagati, 1,200 m, 25 Jan 1996, M. Cerón C. et al. 249 (MEXU, SERO, XAL). Mun. Santa María Tepantlali, 1,728 m, 25 Sep 2020, F. Nicolalde-Morejón et al. 3362-3367 (CIB); 2,147 m, 15 May 2011, G. Juárez-García 3871 (MEXU); 1,728 m, 25 Sep 2020, L. Martínez-Domínguez et al. 1994-1995 (CIB, MEXU), 1996-2000 (CIB). Mun. Totontepec Villa de Morelos, 1,300 m, 7 Dec 1989, E. Vargas-Ruíz 476 (MEXU); 1,900 m, 21 Apr 1986, J. Rivera-Reyes & Gary J. Martin 246 (MEXU); 1,700 m, 15 Jul 1987, E. Velasco-López & G.J. Martin 60 (MEXU); 1,900 m, 6 Jan 1988, J. Rivera-Reyes & G.J. Martin 920 (MEXU); 2,000 m, 16 Sep 1987, W. Ruíz S. 46 (MEXU).

Figures

Figure 7. Plants of Ceratozamia in habitat A C. kuesteriana B C. latifolia C C. leptoceras D C. matudae E C. mexicana F C. miqueliana G C. mirandae H C. mixeorum I C. morettii J Epiphytic C. morettii.

Figure 21. Distribution of Ceratozamia species A C. mixeorum. B C. morettii. C C. norstogii D C. oliversacksii.