Ceratozamia whitelockiana Chemnick & T.J.Greg., Phytologia 79(1): 51. 1996 ( "1995" )

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

34. Ceratozamia whitelockiana Chemnick & T.J.Greg., Phytologia 79(1): 51. 1996 ( "1995")

Fig. 30

Type.

Mexico. Oaxaca: Vicinity of Metates, south of Valle Nacional , 628 m, 10 May 1995, J. Chemnick & T. Gregory 5 (holotype: HNT [n.v.]; isotypes: FTG!, XALU [n.v.]) .

Description.

Stem 20-80 cm long, 18-30 cm in diameter, epigeous, decumbent. Cataphylls 2-5 × 2-5 cm wide at the base, persistent, triangular, reddish brown, densely brown tomentose at emergence, partially tomentose at maturity, apex acuminate. Leaves 3-10, 129-250 cm long, descending, light green and glaucous at emergence with whitish gray trichomes, glabrous at maturity. Petiole 60-140 cm long, terete, linear, green in mature leaves; with 3-22 thin prickles, 0.06-0.39 cm long. Rachis 70-160 cm long, terete, linear, greenish in mature leaves, unarmed. Leaflets 20-48 pairs, opposite to subopposite, insertion in one plane, lanceolate, generally longitudinally 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 25-38.5 × 2.0-3.7 cm, 1.6-3.1 cm between leaflets; articulations 0.5-1.4 cm wide, green. Pollen strobili 20-30 cm long, 3-5 cm in diameter, generally solitary (1-2), cylindrical, erect, greenish at emergence with reddish trichomes, greenish yellow with reddish brown trichomes at maturity; peduncle 15-25 cm long, 1.2-1.9 cm in diameter, glabrous or with trichomes scarce reddish brown to brown; microsporophylls 1.5-3.0 × 0.8-1.5 cm, elliptic with a non-recurved distal face and a lobate fertile portion, infertile portion 0.40-0.50 cm long and linear with straight horns 0.38-0.50 cm long, 0.50-1.0 cm and a right angle between the horns. Ovulate strobili 14-20 cm long, 7-10 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 1-4 cm long, 1.0-1.8 cm in diameter, erect, glabrous or with trichomes scarce, reddish brown; megasporophylls 24-40, 4-5 orthostichies with 5-8 sporophylls per orthostichy, 1.7-2.2 × 4.5-5.1 cm, with a truncate distal face, horns straight and 0.98-1.4 cm long, 0.95-1.3 cm between horns and an acute angle between the horns. Seeds 2.1-2.7 cm long, 1.4-1.8 cm in diameter, ovate, sarcotesta whitish yellow to yellow when immature, light brown at maturity.

Distribution and habitat.

Ceratozamia whitelockiana is endemic to the Sierra Norte of Oaxaca (Mexico), between 500 to 1,800 m in La Chinantla area (Fig. 29B ). It occurs in the elevational gradient of evergreen tropical forest with Quercus sp. and cloud forest with Oreomunnea mexicana (Standl.) J.-F.Leroy on karstic rocks.

Etymology.

This species was named in honor of Loran Whitelock for his contributions to cycad biology ( Chemnick and Gregory 1996).

Common names.

None recorded.

Uses.

None recorded.

Conservation status.

( IUCN 2021). Ceratozamia whitelockiana is listed as "Endangered (EN)" under criteria A2c; B1ab(i,ii,iii,v)+2ab(i,ii,iii,v); C1.

Discussion.

Ceratozamia whitelockiana is similar to C. mixeorum in leaf morphology; the only difference is the sparse prickles in C. whitelockiana (between 3 to 22, in number), whereas C. mixeorum has more than 28 prickles. Additionally, the length of the petiole is very long in relation to the total size of the leaf in C. whitelockiana . In reproductive structures, the ovulate strobili in C. whitelockiana have a long peduncle 12-23 cm and the fertile portion has 4-5 orthostichies with 5-8 sporophylls per orthostichy and the pollen strobili have a long peduncle that is the same size as the fertile part or longer (Fig. 30 A, C ). In contrast, C. mixeorum has ovulate strobili with a short peduncle from 1-4 cm long and pollen strobili with peduncles shorter than the fertile area.

Specimens examined.

Mexico. Oaxaca: 660 m, 29 Jun 1977, T.B. Croat 39751 (MO). Mun. Ixtlán de Juárez, 1,640 m, 29 Jan 1998, Y. Arellanes C. et al. 283 (SERO); 1,640 m, 21 Aug 1998, Y. Arellanes C. et al. 413 (MEXU, MO, SERO). Mun. San Felipe Usila, 24 Oct 1994, P. Osorio H. 312 (MEXU). Mun. San Juan Bautista Valle Nacional, 650 m, 24 Sep 2020, F. Nicolalde-Morejón et al. 3346 (CIB); 650 m, 24 Sep 2020, L. Martínez-Domínguez et al. 1968 (CIB, MEXU); 500 m, 22 Jan 2001, S. Avendaño R. 5375 (MEXU); 518 m, 22 Jan 2001, T.W. Walters 2001-39-D,E (XAL). Mun. San Juquila Vijanos, 1,900 m, 15 Nov 1996, X. Munn et al. 233 (XAL). Mun. San Pedro Sochiapam, 1,682 m, 2 Nov 2016, M.B. Velasco-Pichardo et al. 225 (MEXU). Mun. San Juan Tepeuxila, 1,538 m, 9 May 2008, J.E. Rivera-Hernández 4289 (MEXU, XAL); 1,538 m, 30 Jul 2008, J.E. Rivera-Hernández 4380 (MEXU). Mun. Santiago Comaltepec, 1,750 m, 8. Jan 1995, A. Rincón G. et al. 516 (MEXU, MO, XAL); 560 m, 24 Sep 2020, F. Nicolalde-Morejón et al. 3348-3355 (CIB); 560 m, 24 Sep 2020, L. Martínez-Domínguez et al. 1973-1975, 1980 (CIB, MEXU), 1976, 1978, 1979, 1981 (CIB), 1977 (CIB, MEXU, NY); 1,600 m, 10 Jun 1988, R. López-Luna & G.J. Martin 285 (MEXU), 1,760 m, 26 Jan 1988, R. Torres C. & E. Martínez S. 11345 (MEXU).

Figures

Figure 29. Distribution of Ceratozamia species A C. vovidesii B C. whitelockiana C C. zaragozae D C. zoquorum.

Figure 30. Ceratozamia whitelockiana A immature pollen strobili B leaflet variation C mature ovulate strobilus D leaves E seedling.