Ceratozamia chamberlainii Mart.- Dominguez , Nic-Mor. & D.W. Stev. Phytotaxa 317(1): 17-28. 2017.

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 : 96-97

2. Ceratozamia chamberlainii Mart.- Dominguez, Nic-Mor. & D.W. Stev. Phytotaxa 317(1): 17-28. 2017. Figure 3F

Type.

MEXICO. San Luis Potosí: Xilitla , 20 Mar. 2016, L. Martínez-Domínguez et al. 933 ♀ (holotype: CIB; isotypes: MEXU, NY) .

Description.

Stem epigeous, erect and decumbent, 20-60 cm in length, 15-30 cm in diameter. Cataphylls persistent, densely tomentose at emergence, reddish-brown and glabrous at maturity, triangular, apex acuminate, 2.5-5.5 × 1.5-3.5 cm at base. Leaves 5-40, descending, 100-207 cm, reddish-brown at emergence with whitish-grey pubescence, glabrous at maturity. Petiole terete, straight, 30-69 cm, armed with short and robust prickles, blackish-brown in adult leaves. Rachis terete, straight, 65-144 cm, armed with prickles, reddish-brown in mature leaves. Leaflets 20-42, oblong, planar and abaxially curved, not basally falcate, coriaceous, flat, opposite to subopposite, plane, dark green, adaxial and abaxial surfaces glabrous, acuminate and asymmetric apex, attenuate at base, with conspicuous and reddish-brown veins; median leaflets 20-37 × 2.3-4 cm, 1.6-3.5 cm between leaflets; articulations generally reddish-brown, 0.5-1.3 cm wide. Polliniferous strobilus generally solitary (1-2), cylindrical, erect, 26-31 cm in length, 4.8-6 cm in diameter, greenish-brown at emergence, greenish with reddish-brown pubescence at maturity; peduncle tomentose, reddish-brown, 6-10.3 cm in length, 1.6-2 cm in diameter; microsporophylls 1.6-2.3 × 1.1-1.5 cm, not recurved distal face. Ovuliferous strobilus cylindrical, erect, 28-30 cm in length, 9-10.5 cm in diameter, greyish-green with reddish-brown pubescence at emergence, light greyish-brown with reddish-brown trichomes at maturity, acuminate apex; peduncle tomentose, brown to reddish-brown, 4.5-11 cm in length, 1.3-2.5 cm in diameter; megasporophylls 72-190, 1.5-2.5 × 2.3-3.0 cm, prominent distal face, acute angle between horns. Seeds ovoid, sarcotesta whitish-red to pink when immature, light brown at maturity, 3.0-4.0 cm in length, 0.6-1.2 cm in diameter.

Distribution and habitat.

Its range includes the states of San Luis Potosí, Querétaro and Hidalgo (Fig. 9 ). Ceratozamia chamberlainii occurs in the cloud forest on rocky outcrops at 900-1,200 m.

Etymology.

The specific epithet honours Charles Joseph Chamberlain in recognition of his outstanding contributions to knowledge of the biology of the cycads and his fieldwork on Mexican cycads.

Distinguishing features.

This species is distinguished by its petioles and rachis with abundant, short prickles; reddish-brown leaves at emergence with coloured articulations at the leaflet attachment to the rachis in adult leaves. Leaflets are oblong and coriaceous with conspicuous, reddish-brown veins.

Specimens examined.

MEXICO. Hidalgo: Chapulhuacán, Alcántara-Ayala 3650 (FCME), F. Nicolalde-Morejón et al. 2200-2203 (CIB), L. Martínez-Domínguez et al. 429 - 430 (CIB), 441- 443 ♀ (CIB), 447 ♂ (CIB), Vite-Reyes et al. 23 (XAL); La Misión, Castro-Castro et al. 1017 (XAL), Vite-Reyes et al. 20 (XAL) . Querétaro: Landa de Matamoros , A. P. Vovides 1291 (XAL, MEXU), 1288, 1290, 2000 (XAL), E. Carranza 633 (IEB), 3119 (MEXU), F. Nicolalde-Morejón et al. 2192-2199 (CIB); L. Martínez-Domínguez et al. 379, 405 ♂ (CIB), 380-404 (CIB); L. Martínez-Domínguez et al. 408-426 (CIB), 427, 428 ♂ (CIB), Rubio Hiram 6332, 6334 (IEB), 647 (XAL) . San Luis Potosí: Tamazunchale, C. L. Lundell 7235 (IEB); Xilitla, F. Nicolalde-Morejón et al. 2407-2420 (CIB), L. Martínez-Domínguez et al. 924 - 932 (CIB); T. W. Walters, TW-2001-04-A (XAL) .

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 9. Distribution map of Ceratozamia sabatoi, C. latifolia, C. zaragozae, C. kuesteriana, C. hildae, C. fuscoviridis and C. chamberlainii.