Ceratozamia mexicana Brongn. Ann. Sci. Nat., Bot. ser. 3, 5: 7-8, t. 1. 1846.

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 : 105-107

9. Ceratozamia mexicana Brongn. Ann. Sci. Nat., Bot. ser. 3, 5: 7-8, t. 1. 1846. Figures 3L , 11

Type.

MEXICO, from Ghiesbrecht, cult. in Hort. Bot. Parisiensis, 1845, Brongniart s.n. (holotype: P). Epitype (designated by Vovides et al. 2016). MEXICO. Veracruz: Totutla , 08 Sep. 1982, J. Rees & A. P. Vovides 1688 (XAL) .

Ceratozamia intermedia Miq. Tijdschr. Wis-Natuurk. Wetensch. Eerste Kl. Kon. Ned. Inst. Wetensch. 1 (4): 40-41. 1848. Neotype (designated here). MEXICO. Veracruz: Puente Nacional , 13 Mar. 1985, G. Castillo-Campo & Medina 4275 (XAL).

This specimen represents part of the variation found in Ceratozamia mexicana and the locality is on the collection route that was followed by 19th century collectors to the centre of Veracruz.

Ceratozamia longifolia . Miq. Tijdschr. Wis-Natuurk. Wetensch. Eerste Kl. Kon. Ned. Inst. Wetensch. 1 (4): 40. 1848. Neotype (designated here). MEXICO. Veracruz: Zacuapam , Apr. 1913, Purpus s/n (MO [6362]).

This locality is a historic collection from the central region of Veracruz for Ceratozamia mexicana , which was one of the most collected cycads during the 19th century.

Ceratozamia mexicana Brongn. var. mexicana .

Ceratozamia longifolia var. Ceratozamia longifolia minor . Miq. Tijdschr. Wis-Natuurk. Wetensch. Eerste Kl. Kon. Ned. Inst. Wetensch. 2 (4): 290. 1849. Neotype (designated here). MEXICO. Veracruz: Teocelo , 23 Dic. 1975, M. G. Zola 146 (XAL).

This locality is on the historic collection route for Ceratozamia and represents the northern end of the distribution for Ceratozamia mexicana where plants with lower leaflet widths have been recorded.

Ceratozamia mexicana var. longifolia . (Miquel) Dyer. Biol. cent.- amer., Bot. 3 (16): 193. 1884. Type: Based on Ceratozamia longifolia .

Description.

Stem epigeous, erect and decumbent, 20-80 cm in length, 20-45 cm in diameter. Cataphylls persistent, densely tomentose at emergence, reddish-brown and partially tomentose at maturity, triangular, apex acuminate, 2-6 × 2.5-6 cm at base. Leaves 5-55, descending, 100-270 cm, light green at emergence, brown pubescence, glabrous at maturity. Petiole terete, straight, 30-93 cm, armed with short and thin prickles, dark green in adult leaves. Rachis terete, straight, 56-154 cm, armed with prickles and unarmed, green in adult leaves. Leaflets 25-42, lanceolate, mostly planar, basally falcate, coriaceous, flat, 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 29-51 × 2.3-3.7 cm, 1.8-4 cm between leaflets; articulations green, 0.6-1.5 cm wide. Polliniferous strobilus generally solitary (1-2), cylindrical, erect, 24-40 cm in length, 5.5-7.6 cm in diameter, greenish-yellow at emergence, greenish-yellow with blackish pubescence at maturity; peduncle tomentose, reddish-brown to light brown, 3.5-5 cm in length, 1.8-2.3 cm in diameter; microsporophylls 1.6-2.7 × 0.9-2.1 cm, non-recurved distal face. Ovuliferous strobilus generally solitary (1-2), cylindrical, erect or pendular, 23.5-38 cm in length, 10.5-14.6 cm in diameter, dark green with blackish pubescence at emergence, dark green with black and grey trichomes at maturity, acuminate apex; peduncle tomentose, brown to reddish-brown, 8-11.5 cm in length, 2.5-3 cm in diameter; megasporophylls 55-224, 2-4 × 4.4-5.3 cm, prominent distal face, obtuse angle between horns. Seeds ovoid, sarcotesta whitish-yellow to yellow when immature, light brown at maturity, 2-3.3 cm in length, 1.5-2.5 cm in diameter.

Distribution and habitat.

Endemic to Mexico from the River La Antigua drainage system within Xico, Teocelo and Coatepec municipalities to south end of Sierra Madre Oriental in Veracruz state, between 500-1,300 m in cloud forest (Figure 8 ).

Etymology.

The epithet is derived from the country of origin of the material for the description of the genus.

Distinguishing features.

Ceratozamia mexicana is distinguished by its lanceolate, coriaceous and flat leaflets with a symmetric apex, ovulate strobilus dark green with black and grey trichomes at maturity, and a prominent distal face with an obtuse angle between horns (Fig. 11 ).

Specimens examined.

MEXICO. Veracruz: Coatepec, P. Zamora C. 2450 (MEXU, XAL); Comapa, F. Nicolalde-Morejón et al. 2146-2156 (CIB), L. Martínez-Domínguez et al. 164, 716-730 (CIB); Puente Nacional, G. Castillo-Campos & M. E. Medina 4299 (XAL); Sochiapa, M. Vázquez-Torres 8589 (CIB); Teocelo, F. Nicolalde-Morejón et al. 2273-2278 (CIB), M. G. Zola 146 (XAL), M. Vázquez-Torres 4865 (CIB), L. Martínez-Domínguez et al. 731-750, 764-770 (CIB); Tlaltetela, F. Nicolalde-Morejón & L. Martínez-Domínguez 2246, 2253-2256 (CIB), L. Martínez-Domínguez & F. Nicolalde-Morejón 584-586, 620, 628-635 (CIB); Totutla, A. P. Vovides 730-733, 748 (XAL), Brigada T. Walters s/n (XAL), F. Nicolalde-Morejón et al. 2279-2281 (CIB), F. Vázquez B. 730 (XAL), J. Rees 6344 (IEB), J. Rees & A. P. Vovides 1660, 1672, 1689 (XAL), L. Martínez-Domínguez et al. 704-707, L. Martínez-Domínguez et al. 752-758 (CIB); Xico, L. Martínez-Domínguez & F. Nicolalde-Morejón 640-648 (CIB).

Taxonomic comments.

The taxonomy of Ceratozamia mexicana has undergone constant changes since its original publication in 1846. The identity of this binomial was ambiguous for several decades. This taxonomic uncertainty was due to the complexity of relationships with some of the other names published by Miquel during the immediately succeeding years (1847, 1848 and 1849), following the original publication of the genus -namely, C. brevifrons , C. robusta , C. intermedia , C. longifolia , and C. latifolia . Later on, some names were placed in synonymy and others were characterised as nomina nuda; in particular, C. brevifrons was listed as a synonym of C. mexicana under the assumption that it was in fact a juvenile form of the latter (see Miquel 1848, 1861).

In further taxonomic treatments of Ceratozamia -specifically, in De Candolle (1864-1868) and including Miquel’s Nouveaux matériaux pour servir à la connaissance des Cycadées (1868-1869a, b)- this nomenclatural status was maintained. In his mature work, Miquel considered the variation observed between juveniles and adults was due to the corresponding ontogenetic modifications and collapsed into synonymy with C. mexicana all five species previously described.

Half a century later, Schuster (1932) circumscribed the genus to include only two species: Ceratozamia kuesteriana and C. mexicana , with two varieties and two forms. However, in the first modern taxonomic treatment ( Vovides et al. 1983) and continuing with the typification of names within the genus ( Stevenson and Sabato 1986), the type species was circumscribed to the central region of Veracruz. In this context, Vovides et al. (1983) attributed a wide geographic distribution and high variation of morphological characters to C. mexicana while recognising three varieties: C. mexicana var. mexicana , C. mexicana var. latifolia (Miq.) Schuster and C. mexicana var. robusta (Miq.) Dyer.

The original Ceratozamia mexicana specimens were collected by the Belgian botanist and explorer A. B. Ghiesbreght, who probably did his fieldwork in the region of Huatusco, Veracruz. This location is recognised as part of his route for botanical collections between 1835 and 1838 ( Barnhart 1965; Sartorius 1990; Rzedowski et al. 2009). Besides the "El Mirador" locality, mentioned by Thiselton-Dyer (1884) and Schuster (1932) as the main reference place, the species still exists in Huatusco. Due to coffee cultivation, the original vegetation has been replaced almost in its entirety. However, the species still occurs in the wild in relictual secondary vegetation within a property called "Hacienda Zacuapam". This property was part of a former "El Mirador" hacienda, early in the XIX century ( Sartorius 1990).

Figures

Figure 3. Shapes of leaflets. A C. latifolia B C. kuesteriana C C. morettii D C. sabatoi E Ceratozamia brevifrons F C. chamberlainii G C. decumbens H C. fuscoviridis I C. tenuis J C. totonacorum K C. delucana L C. mexicana.

Figure 8. Distribution map of Ceratozamia tenuis, C. totonacorum, C. morettii, C. mexicana, C. delucana, C. decumbens and C. brevifrons.

Figure 11. Ceratozamia mexicana. A Adult plant in habit B Leaf at emergence C Detail of pollen strobili D Microsporophyll E Megasporophyll F Detail of ovulate strobili G Seeds.