Chamomile
Tormentil
Red and Yellow dye.
Wattle flowers are yellow.
betony
Vegetable flowers are not all yellow.
Probably chamomile. The flowers are harvested for teas and they have distinct demulcent purpose. Great for calming the stomach providing you aren't allergic to them.
Primroses are a type of primula with yellow flowers.
if i am correct the marigold has yellow flowers and has "mar" in its name.
Dyer's CoreopsisThis variety of the common yellow coreopsis flower (its scientific name is Coreopsis tinctoria) produces a deep yellow shade when used for dyeing without any additional chemicals. Dyer's coreopsis grows wild in many places in North America and is easy to grow at home. You can also use the plants (without the flowers) to create a greenish-brown shade. You will need the same weight of flowers or plants as the weight of the fibers you plan to dye.EucalyptusThere are many types of eucalyptus, and each provides a different result when dyeing. However, many eucalyptus varieties produce a lovely bright orange on fibers when used for dyeing without additional chemicals. The smell of eucalyptus can be quite strong when it's boiled during the dyeing process, however, so it may be best to work with it outside on a portable hot plate unless you really enjoy its scent. You can also collect some eucalyptus bark, which makes a pale green when used for dyeing. An equal weight of leaves and fiber is needed for dyeing.
It is a yellow-brown cyristaline compound used as a mordant in dyeing and as an etching compound.
Whattle (Acacia so. ) flowers are yellow. There is some variation in the brightness of the flowers between whattle species. Some species have quite bright yellow flowers, whereas others have pale yellow flowers. Some species have very pale flowers which appear to be white, but the most common colour is yellow.
Hummingbirds will visit red flowers and yellow flowers with the same frequency.