Ceratozamia robusta

Description. Stem 30 - 100 cm long, 20 - 40 cm in diameter, epigeous, erect and decumbent. Cataphylls 5.0 - 9.0 x 3.5 - 7.5 cm wide at the base, persistent, long triangular, reddish brown, densely brown tomentose at emergence, partially tomentose at maturity, apex acuminate. Leaves 10 - 50, 138 - 266 cm long, ascending, dark brown at emergence, green and glabrous at maturity. Petiole 56 - 85 cm long, terete, linear, brown in young leaves, green in mature leaves; with 27 - 55 robust prickles, 0.48 - 0.70 cm long. Rachis 60 - 190 cm long, terete, linear, brown in young leaves, green in mature leaves, with prickles. Leaflets 20 - 45 pairs, opposite to subopposite, insertion in one plane, lanceolate, in general longitudinally planar, not basally falcate, papyraceous, flat, green with adaxial side glabrous and abaxial side glaucous, distal end with entire margins, acuminate and asymmetrical at the apex, attenuate at base, with conspicuous and light-green veins; median leaflets 28 - 42 x 2.5 - 4.0 cm, 3.0 - 4.5 cm between leaflets; articulations 0.2 - 0.8 cm wide, green. Pollen strobili 50 - 70 cm long, 7.0 - 8.5 cm in diameter, solitary, cylindrical, erect, light green to yellowish green with blackish trichomes at emergence, yellowish cream with reddish brown trichomes at maturity; peduncle 10 - 15 cm long, 2.5 - 3.2 cm in diameter, tomentose, reddish brown to brown; microsporophylls 2.33 - 3.0 x 1.14 - 1.90 cm, obconic with a non-recurved distal face and deeply lobate fertile portion, infertile portion 0.45 - 0.65 cm long and rounded with curved horns 0.26 - 0.40 cm long, 0.55 - 0.75 cm and a right angle between the horns. Ovulate strobili 26 - 40 cm long, 11 - 14.5 cm in diameter, solitary, cylindrical, erect, dark green at emergence, dark green with scarce blackish trichomes at maturity, acuminate apex; peduncle 5.0 - 11.0 cm long, 2.5 - 4.0 cm in diameter, erect, tomentose, reddish brown; megasporophylls 153 - 280, 8 - 14 orthostichies with 17 - 20 sporophylls per orthostichy, 1.7 - 2.5 x 2.3 - 3.5 cm, with a prominent distal face, horns straight and 0.38 - 0.50 cm long, 1.35 - 1.60 cm between horns with a right angle between the horns. Seeds 2.5 - 3.5 cm long, 1.9 - 2.5 cm in diameter, ovate, sarcotesta whitish yellow to yellow when immature, light brown at maturity.