Carl Miller kindly sent in details of jambu and a link to Wikipedia. I had seen this defined as a type of cress and Wikipedia says: For culinary purposes, small amounts of shredded fresh leaves add a unique flavour to salads. Cooked leaves lose their strong flavour and may be used as leafy greens. Both fresh and cooked leaves are used in dishes (such as stews) in Northern parts of Brazil, especially in the state of Pará, often combined with chillies and garlic to add flavor and vitamins to other foods. A related species is used in several Southeast Asian dishes, such as salads. Consumption of portions or whole flowers have been reportedly used to offset the intense heat of chillies and peppers.
