Ceratozamia norstogii

D.W.Stev. (1982)

Common names

Norstog's horncone.

Taxonomic notes

The type locality is in the Sierra Madre del Sur. Although first collected in 1925, the species was not formally described until 1982 (Jones 1993).

Description

"A small cycad which in nature develops a slender trunk to about 50 cm long and 10 cm across. Young leaves densely covered with brown hairs. Mature leaves a few in an attractive crown, 1-2 m long, dark green, smooth, glabrous; petiole 20-30 cm long, swollen at the base, armed with sharp prickles; rhachis spirally twisted; leaflets 100-160 on each leaf, 20-50 cm × 0.3-1 cm, linear, sessile, the margins inrolled, apex long tapered, acute to acuminate. Male cones 20-25 cm × 5-8 cm, usually solitary, cylindrical, tawny brown; sporophylls 1.2-1.5 cm × 0.5-0.8 cm, broadly wedge-shaped, with two horns 1-3 mm long; peduncle 2-5 cm long, woolly. Female cones 20-40 cm × 9-12 cm, usually solitary, cylindrical, olive green; sporophylls 2-4 cm × 1.5-3.5 cm, peltate with two stout horns. Seeds 2-3.5 cm × 1.2-1.5 cm, ovoid, smooth, white when ripe.

"Plants can be confused with C. zaragozae which also has spirally twisted leaves but C. norstogii has longer fronds (to 2 m long), ovoid seeds and the apices of its leaflets contract more abruptly to a point. Although the spirally twisted rhachis is usually mentioned as distinctive in this species, it should be noted that some populations do not have this feature" (Jones 1993).

Distribution and Ecology

Mexico: Chiapas, on mountain slopes in shady forests dominated by species of Pinus and Quercus. "Natural populations of this species were decimated by overcollecting soon after its description. Following this poaching, many researchers adopted a policy of not including detailed localities when describing new species of cycads" (Jones 1993).

Remarkable Specimens

No data as of 2026-01-14.

Ethnobotany

Grown, albeit rarely, as an ornamental (Jones 1993).

Observations

No data as of 2026-01-14.

Remarks

Named after Knut Norstog, a contemporary American research worker specialising in cycads (Jones 1993).

The leathery inrolled leaflets represent a morphological adaptation to the seasonally dry climate (Jones 1993).

Citations

Stevenson, D. W. 1982. Brittonia 34(2):181.

See also

Pérez-Farrera, M.A., A.P. Vovides, and C. Iglesias. 2001. The cycad Ceratozamia norstogii D.W. Stev. (Zamiaceae) from southern Mexico: new information on distribution, habitat and vegetative morphology. Botanical Journal of the Linnean Society 137:71-76.