clustered lady's slipper: clusters of several short stems each having 2 broad leaves and 2-4 drooping brownish to greenish flowers with pouches mottled with purple; British Columbia to central California and northern Colorado
lady's slipper: any of several chiefly American wildflowers having an inflated pouchlike lip; difficult or impossible to cultivate in the garden
threonine: a colorless crystalline amino acid found in protein; occurs in the hydrolysates of certain proteins; an essential component of human nutrition