The 2.5 million North Americans of Welsh heritage are celebrating today with wistfulness for their homeland. This national Welsh holiday honors St. David, the 6th-century patron saint of Wales. Catrin Finch is a Welsh harpist who came by Studio 4A and played the Welsh folk song "Watching the White Wheat." Then we hear the same song sung by Bryn Terfel accompanied by Finch and the London Symphony Orchestra. Barry Wordsworth conducts.