Bluebonnets in the fall.

Walking at dawn in the fall in Texas the yellows and golds and reds of the grasses and leaves tend to dominate.

Fall sunrise in Texas

But look closer, below the red and yellow grasses, and there are round, bright green seed leaves of Lupinus texensis– the Texas bluebonnet. After the heat of summer and the fall rains, around September or October, these emerald gems appear close to the ground. Soon afterwards, especially if there is more rain, the palmate leaves with their pointed hairy leaflets appear. On a morning with heavy dew the moisture collects on these leaves so that they shimmer like silver in the first rays of light, collecting little pearls of moisture at the base of the leaflets.

Dew decked bluebonnets in fall.

As the seedlings of these annuals grow they send down roots that have nodules. As members of the family Fabaceae they form symbiotic relationships with bacteria that fix gaseous nitrogen for the plant. This nitrogen gets passed on into the soil enriching it for other plants. In return the bacteria get carbohydrates from the plant.

Through winter storms these small green leafy rosettes wait for spring and the chance to flower. With good fall and spring rains fields of them will appear around March and April. The spike inflorescences of multiple blue flowers are easily identified as belonging to the pea family with the banner, wing and keel forming each flower.

Field of bluebonnets in Texas spring

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