Watercress

APPEARANCE: In Hong Kong markets this vegetable appears in great heaps — and only during the winter. Identify it by the red-purple tint and irregular shape of its small leaflets. Note, too, the small white roots often found growing at the bases of leaves along the lower stems.

QUALITY: Tender green tips are best; buy as little of the thick, tough lower stems as possible.

COMMENTS: Apparently Hong Kong was responsible for introducing this plant to China around the turn of the 20th century. Easy to grow and of a familiar cabbage flavor, it has since joined the crowd of common market and family dinner-table vegetables.