Etymology: Honoring American botanist and eminent student of cycads Knut Norstog. Historical notes: Named in 1982 by American botanist Dennis Stevenson, although known since as early as 1925. Distinguishing features: Narrow leaflets, longer leaves often but not always twisted, prickly rachis. Distribution and habitat: A narrow endemic in Chiapas state, Mexico, in seasonally dry pine-oak forests in the Sierra Madre del Sul. Conservation status: Endangered. 1997 IUCN Red List of Threatened Plants category V.
Description:
Plants arborescent, or acaulescent; stem 12-130 cm long, stem 13-22 cm diam. Leaves 5-15 in crown. New growth emerging bronze, red or chocolate brown. Leaves dark green, semiglossy, 69-135 cm long, flat (not keeled) in section, with 66-130 leaflets; vernation straight; rachis distinctly spirally twisted; petiole 9-39 cm long, armed with prickles. Leaflets not clustered, linear, symmetric, broadest below middle, falcate, strongly discolorous, thick or leathery; margins incurved; median leaflets 22-57 cm long, 3-5 mm wide. Pollen cones yellow-green, narrowly ovoid-cylindrical, 25-36 cm long, 3.8-5.1 cm diam.; peduncle 4.5 cm long; microsporophyll lamina 10-14 mm long, 8-11 mm wide, with two horns 1-2 mm long. Seed cones brown, ovoid-cylindrical, 21-37 cm long, 9-13 cm diam.; peduncle 6-10 cm long; megasporophyll 41-55 mm long, with an expanded peltate apex 38-52 mm wide, with two horns 2-6 mm long. Seeds ovoid, 24-29 mm long, 15-21 mm wide; sarcotesta white, aging to
brown.
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