Pteridosperm Anatomy and Its Relation to That of the Cycads.

Pteridosperm Anatomy. 41 represented on the south-facing side of the gorge. Further up the gorge this gives place also to the Pignon-Juniper association and then to Pignon alone. Populus treiimtoides is abundant along the riverside. Further up still the gorge opens out and Douglas flr, Engelmann spruce and aspen appear on the upper slopes of the valley. Eventually a broad valley is entered, sub-alpine meadow containing much Potentilla fruticosa with Picea Engehnanni and Pinus Murrayana (the lodge-pole pine) which is absent from the Pike's Peak region, though it forms a well-mai ked altitudinal zone further north. Tennessee Pass, crossing the Continental divide at 10,246 feet, was reached about dusk and here are close stands of lodge-pole pine-perhaps flre relicts-among great stretches of bare grass-covered mountain.