Ceratozamia alvarezii 學問
Trunk subglobose, 10-50 cm long, partially subterranean, becoming cylindrical with age, branching freely, 8.9-17.5 cm diam. and protected by persistent petiole bases. Cataphylls stipulate, lanulose, 2.1-5 cm long, 1.5-3 cm wide, brown. Leaves 4-18, pinnate, spirally arranged forming an open crown, 54-109 cm long, 31.5-61 cm wide. Petiole 14-42 cm long, rachis 25-66 cm long, both ascending, tomentose, especially at the base, armed with short stout prickles 2-5 mm, which decrease toward the apical part of the rachis, occasionally mildly twisted. Leaflets 24-62, linear-lanceolate, opposite to subopposite, flat, coriaceous, margins entire, pubescent when immature, glabrous with age, adaxial surface dark green, abaxial surface light green, 16-32.5 cm long, 4-9 mm wide, venation visible on the abaxial surface, number of veins 5-9, distance between veins 0.05-1 mm. Microstrobilus cylindrical to conical, light green to olive green upon emergence, light yellow to creamy yellow when mature, 11-31 cm long, 2.5-4.5 cm diam., peduncle tomentose, 4-5 cm long, 1-1.8 cm diam. Microsporophylls numerous, inserted spirally with vertical rows, cuneiform, 1.4-1.7 cm long, 0.6-0.9 cm wide, bicornate in the distal part, with the fertile portion covering 1/2-2/3 of the abaxial surface excluding the horns. Microsporangia numerous in sori of 3-4, longitudinally dehiscent. Megastrobilus cylindrical to barrel-shaped, olive green upon emergence, brown ochre when mature, 14.5-19 cm long, 5.7-10.5 cm diam., peduncle tomentose, 4.5-6.5 cm long, 1.8-2.2 cm diam. Megasporophylls numerous, peltate, inserted spirally on the cone axis forming apparent vertical rows, 2.8-4.5 cm long, 1.5-2.9 cm wide, distal end hexagonal, bicornate, with brown ochre tomentum on the lobulate part around the horns. Seed ovate, sarcotesta white when immature and creamy yellow when mature, sclerotesta smooth and beige in colour, 1.7-2.5 cm long, 1.7-2.0 cm diam. with 7-9 radial ridges. Chromosome number 2n = 16.
A newly discovered species from the Chiapus region of Mexico. Ceratozamia alvarezii principally occurs in oak forest at an altitude of 950 m.