Fennel and Celery Root Salad

Name: Fennel and Celery Root Salad
Ingredients: 1 small fennel bulb, very thinly sliced on a mandoline, plus ¼ cup coarsely chopped fennel fronds; ½ small celery root (celeriac; about 6 ounces), peeled, very thinly sliced on a mandoline; 1 small head of Treviso or Chioggia radicchio, outer leaves separated, heart quartered; Leaves from 1 bunch celery (about 1 cup); ½ cup parsley leaves with tender stems; 1 tablespoon marjoram leaves; Kosher salt, freshly ground pepper; 3 tablespoons olive oil, preferably new-harvest; 2 tablespoons fresh lemon juice