Thalictrum polycarpum Thalictrum polycarpum seeds with mm ruler on right. Thalictrum polycarpum seeds in a 1/4 tsp (2 cm diameter). Thalictrum polycarpum seedlings germinated within a growth chamber set at a 25/15°C (77/59°F) day/night temperature with a 12-hour day photoperiod of cool-white fluorescent light. Thalictrum polycarpum seedlings treated with 0 (right) or 1,000 (left) ppm Gibberellic Acid. Thalictrum polycarpum seedlings growing in 48-cell liners at the Berry Seed Bank research greenhouse located in Portland, Oregon. Thalictrum polycarpum seedlings growing in 48-cell liners at the Berry Seed Bank research greenhouse located in Portland, Oregon. Thalictrum polycarpum rootball of seedlings growing in 48-cell liners at the Berry Seed Bank research greenhouse located in Portland, Oregon. Thalictrum polycarpum rootball of seedlings growing in 48-cell liners at the Berry Seed Bank research greenhouse located in Portland, Oregon. Thalictrum polycarpum roots. Thalictrum polycarpum roots.