1. (

• bluebonnet ,
• buffalo_clover ,
• Texas_bluebonnet ,
• Lupinus_subcarnosus

) low-growing annual herb of southwestern United States (Texas) having silky foliage and blue flowers; a leading cause of livestock poisoning in the southwestern United States ;

2. (

• Balmoral ,
• bluebonnet

) a brimless dark blue Scottish cap with a flat top and a plume on one side ;