Texas bluebonnet

Lupinus texensis, the Texas bluebonnet, is an erect winter annual herb of the Fabaceae endemic to Texas, typically 15-40 cm tall, with a slender taproot and one to several pubescent branched stems arising from a basal rosette. The palmately compound leaves bear five (rarely four to seven) obovate to oblanceolate leaflets 2-4 cm long, dark green and silky-pubescent on both surfaces but more densely so beneath, narrowed to a slender petiole 3-6 cm long. The inflorescence is a dense terminal raceme 6-15 cm long carrying 20-50 fragrant pea-flowers in spirals. Flowers are 9-11 mm long with a deep azure-blue standard featuring a white central spot that turns wine-red with age, oblong wings that conceal the keel, and a hairy calyx with prominent upper and lower lips. The fruit is a flattened, oblong, densely hairy legume 2-4 cm long containing four to six mottled grey-brown seeds that are ejected explosively at maturity. The species flowers in spring on limestone-derived clay and sandy loam soils of roadsides, prairies and open hillsides across central Texas, where it forms spectacular blue carpets and is the state's official flower.