As  historian Jack Maguire so aptly wrote, "It's not only the state flower but also a kind of floral trademark almost as well known to outsiders as cowboy boots and the Stetson hat." He goes on to affirm  that  "The  bluebonnet  is  to  Texas what the shamrock is to Ireland, the cherry blossom to  Japan, the lily to France, the rose to England and the tulip to Holland."

      On March 7, 1901, the Twenty-seventh Texas Legislature adopted the bluebonnet, flower of the annual legume Lupinus subcarnosus, as the state flower. The flower's popular name derives from its resemblance to a sunbonnet. It has also been called buffalo clover, wolf flower, and, in Spanish, el conejo ("the rabbit"). On March 8, 1971, the legislation was amended to include L. texensis and "any other variety of bluebonnet not heretofore recorded." At least four other species of bluebonnet grow in Texas: L. havardii, L. concinnus, L. perennis, and L. plattensis. Contrary to various folk stories and legends claiming that the plant originated outside the state, L. texensis and L. subcarnosus are native to Texas. In 1933 the legislature adopted a state flower song, "Bluebonnets," written by Julia D. Booth and Lora C. Crockett. Also in the 1930s the Highway Department began a landscaping and beautification program and extended the flower's range. Due largely to that agency's efforts, bluebonnets now grow along most major highways throughout the state.*

      The flower usually blooms in late March and early April and is found mostly in limestone outcroppings from north central Texas to Mexico. Its popularity is widespread. Although early explorers failed to mention the bluebonnet in their descriptions of Texas, Indian lore called the flower a gift from the Great Spirit. The bluebonnet continues to be a favorite subject for artists and photographers, and at the peak of bloom, festivals featuring the flower are held in several locations.*  Texas State Historical Association*

Texas Official State Song "Bluebonnets"
Bluebonnets
words and music by Julia D. Booth and Lora C. Crockett
 
When the pastures are green in the springtime
And the birds are singing their sonnets,
You may look to the hills and the valleys
And they’re covered with lovely Bluebonnets.

Blue is the emblem of loyalty,
They’re as blue as the deep, deep sea,
Their smiling faces bring gladness,
For they bloom for you and for me.
 
Bluebonnets, so gorgeous and stately,
In your mantle of blue and of green,
In the spring when you’re in your full glory,
You’re the loveliest sight ever seen.
 
You’re beautiful when you sway in the sunshine,
You look like waves of the sea,
Ah, Texas was wise in her choice of a flow’r,
So we offer our homage to thee.
 
Chorus:
Bluebonnets, blue lovely Bluebonnets,
More beautiful than all the rest.
Texas chose you for her flower,
And we love you best, Bluebonnets.