The yellow herbs of summer: Yellow bedstraw.
A tasty lymphatic.
Cut flowering branches about 10 cm (4") above ground, on a dry meadow in mid-July (up here, that is). Yellow bedstraw is perennial, and in places it's not all that common, so don't take more than one third of any given plant. Yellow bedstraw also hybridizes easily with at least one white-flowering Galium species; the hybrids are lighter yellow in their flowerclouds, and they don't always have the exquisite honey scent of the true species. Dry your yellow bedstraw in hanging bundles, or cut into 2-3 cm (1") bits on an old sheet on some newspapers.
Cleavers, which can be used instead of the "true" yellow bedstraw (or perhaps it's the yellow bedstraw that can be used instead of cleavers?), is an annual which grows profusely in vegetable beds and on similar moist rich soil. Pull up any cleavers you can lay your hands on, remove brown and yellow bits (and dirt), and dry the rest.
Tea: Both these Galium species are excellent lymphatics. Use them in allergies, in urinary tract infections, and as a tea to give you minerals and trace elements.