• Wind Cave National Park - Two Worlds

    Wind Cave

    National Park South Dakota

Seed Study - Aristida purpurea

Aristida purpurea - Red Three Awn

Aristida purpurea - Red Three Awn

NPS Graphic

Species: Aristida purpurea
Common name: red three awn

Vegetative identification: Tufts of long hair protrude from each side of the sheath at the collar. The sheath is split partway down then over lapping. Sheath also has prominent veins and translucent margins. New leaves are rolled in the bud. Leaf blades are narrow and bristle like, often curled and twisted. Leaf surface and margins are rough to the touch.

 

Aristida purpurea – red three awn
Average number of good seeds per gram bulk matter: 238 (111)
Average number of good seeds per gram cleaned: 336 (150)
Commercial estimates of seeds per gram: 551
Percent seed: n.m.
Percent live: 89
Collection dates: September 23; October 6, 7, 11
Collection effort: 74 grams in 7 person hours
Collection notes: Plants are generally widely dispersed but quite visible when in fruit. The awns do not compact well, so it is difficult to collect and pack into bags.
Cleaning notes: Bulk matter consisted of awns, glumes and empty seed structures. Clean seed was only hard seed that included the lemma, awns and glumes. The seed broke easily while being checked for hardness, but generally hard seeds were dark and enclosed in light glume/lemma.

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