asian flower pigeonwings aparajita ayurvedic blue asia blue-pea botanic bush butterfly butterfly-pea centrosema clitoria colorant colouring cordofan cordofan-pea decorative dye fabaceae family flora floral foliage food gardening gokarn green herbal horticulture india inflorescence leaves liana macro medicinal nature pea petals pigeon pigment plant say shrub ternatea thailand tropical tropics vine