Ceratozamia tenuis (Dyer) D. W. Stev. & Vovides. Botanical Sciences 94 (2): 419-429. 2016.

Martinez-Dominguez, Lili, Nicolalde-Morejon, Fernando, Vergara-Silva, Francisco & Stevenson, Dennis Wm., 2018, Taxonomic review of Ceratozamia (Zamiaceae) in the Sierra Madre Oriental, Mexico, PhytoKeys 100, pp. 91-124: 110-112

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Ceratozamia tenuis (Dyer) D. W. Stev. & Vovides. Botanical Sciences 94 (2): 419-429. 2016.


12. Ceratozamia tenuis (Dyer) D. W. Stev. & Vovides. Botanical Sciences 94 (2): 419-429. 2016.  Figures 2A, 3I


Hort. Kew Palm House: Thistleton-Dyer s.n. 1881 (lectotype: K). Epitype (designated here). MEXICO. Veracruz: Jilotepec, 19 Jan. 1976, A. P. Vovides 18 (XAL). Type: Based on Ceratozamia mexicana var. tenuis  Dyer Biol. Cent.-Amer., Bot. 3: 193. 1884. Isoepitype (designated here). A. P. Vovides 18 (NY).

Ceratozamia mexicana var. vulgaris  . Schuster. Pflanzener 99: 131. 1932. Neotype (designated here). MEXICO. Veracruz: Xalapa, Chiltoyac, 18 Oct. 2016, Martínez-Domínguez et al. 984 (CIB).

Schuster mentioned “Jalapa” in his treatment and Chiltoyac (Xalapa, Veracruz), which is very near to Xalapa and thus seems appropriate because the plants match the description by Schuster.

Ceratozamia mexicana var. longifolia f. tenuis  (Dyer) Schuster. Pflanzener 99: 132. 1932. Type: Based on Ceratozamia mexicana var. tenuis  .


Stem epigeous, erect and decumbent, 20-100 cm in length, 30-45 cm in diameter. Cataphylls persistent, densely tomentose at emergence, reddish-brown and partially tomentose at maturity, triangular, apex acuminate, 2-6 × 2-5.5 cm at base. Leaves 6-56, ascending, 85-225 cm, dark green at emergence, brown pubescence, glabrous at maturity. Petiole terete, straight, 30-93 cm, armed with short and thin prickles, green in adult leaves. Rachis terete, straight, 56-154 cm, armed with prickles, green in adult leaves. Leaflets 30-56, linear, planar and abaxially curved, basally falcate, papyraceous, caniculate, opposite to subopposite, plane, green, adaxial and abaxial side glabrous, acuminate and symmetric apex, attenuate at base, with conspicuous and light green veins; median leaflets 23-50.5 × 1-2.1 cm, 0.3-2.5 cm between leaflets; articulations green, 0.4-1.4 cm wide. Polliniferous strobilus solitary, cylindrical, erect, 26-50 cm in length, 5-7 cm in diameter, greenish-yellow at emergence, greenish-yellow with blackish pubescence at maturity; peduncle tomentose, reddish-brown to light-brown, 3.7-22 cm in length, 1.2-2.5 cm in diameter; microsporophylls 1.7-2.7 × 1.2-1.9 cm, non-recurved distal face. Ovuliferous strobilus solitary, cylindrical, erect or pendular, 22-35 cm in length, 7.6-13.3 cm in diameter, dark green with blackish pubescence at emergence, dark green with blackish trichomes at maturity, acuminate apex; peduncle tomentose, brown to reddish-brown, 8-16.5 cm in length, 1.5-2.4 cm in diameter; megasporophylls 48-195, 2.7-3.1 × 4.2-5 cm, prominent distal face, right angle between horns. Seeds ovoid, sarcotesta whitish-yellow to yellow when immature, light brown at maturity, 2.5-3 cm in length, 1.3-1.8 cm in diameter.

Distribution and habitat.

Endemic to Mexico in the central Veracruz mountain region at 1,200-1,850 m elevation on volcanic soils with basaltic rocks (Fig. 8). The vegetation type of the habitat is cloud forest.


The specific epithet alludes to thin leaflets.

Distinguishing features.

Characterised by leaflets linear, papyraceous and caniculate with symmetric apex; petiole and rachis armed with thin prickles; new leaves are dark green at emergence; ovulate strobilus dark green with blackish trichomes at maturity, prominent distal face, and right angle between horns.

Specimens examined.

MEXICO. Veracruz: Chiconquiaco, D. Jimeno Sevilla 754 (XAL), J. Rees 1625 (XAL), 1626 (MEXU, XAL), L. Martínez-Domínguez et al. 971-981 (CIB), R. Fernandez-Nava 385 (MEXU); Coacoatzintla, F. Vazquez B. (XAL), G. Castillo-Campos 118 (XAL), L. Martínez-Domínguez et al. 165-184, 273-282, 759 (CIB); Jilotepec, A. P. Vovides 470 (XAL), 471 (MEXU, XAL), 735 (XAL), E. Estrada et al. 757 (MEXU), J. Rees 1620 (XAL), F. Nicolalde-Morejón & L. Martínez-Domínguez 2067-2086 (CIB), L. Martínez-Domínguez et al. 573-583 (CIB), M. G. Zola 667 (MEXU, XAL), R. Ortega J. 525 (XAL), S. Avendaño 5395 (MEXU); Tepetlán, F. Nicolalde-Morejón & L. Martínez-Domínguez 2001-2004 (CIB), 2047-2066 (CIB), 2217-2226 (CIB), L. Martínez-Domínguez et al. 160, 283-293, 545-555 (CIB); Xalapa, L. Martínez-Domínguez et al. 985-987 (CIB).

Taxonomic comments.

This name has been controversial due to a series of transferences and the lack of material. This species was initially described as C. mexicana var. tenuis  ( Thiselton-Dyer 1884) and Schuster (1932) transferred it to form status under the name C. mexicana var. longifolia f. tenuis  . However, its identity has been questioned for decades due to the scarcity of type specimens. The discovery of a specimen collected and examined by Thiselton-Dyer for his protologue description and the subsequent lectotypification of this specimen, has allowed a clearer concept of this taxon ( Vovides et al. 2016). Recently, this entity was transferred to the species level after the analysis of quantitative morphological and anatomical evidence which allowed the separation of populations previously associated with the C. mexicana  and their assignment as a new entity ( Vovides et al. 2016). Individuals in these populations bear correspondence to lectotype specimens in the Royal Botanic Gardens Kew herbarium, which correspond to Ceratozamia mexicana var. tenuis  ( Vovides et al. 2016). Two specimens were incorrectly designated by Vovides et al. (2016) as epitypes [A. Vovides 018 (XAL, NY)]. According to the International Code of Nomenclature ( McNeil et al. 2012), we correct the designation of the epitype and designate an isoepitype (Section 2, Article 9, Recommendation 9C). Finally, we note that the historical Ceratozamia  populations from Jilotepec and Coacoatzintla have been associated to the C. mexicana  species since the morphological work of Chamberlain (1912).