| To examine the ontogenetic bases of different flower forms, the ontogenies of five species representative of five sections of Agalinis were compared using a set of developmental markers. Each species exhibited a distinctive pattern of development, from initiation of the floral primordia through floral organ enlargement to anthesis. Each species also shared a unique combination of developmental similarities with the other species. Early developmental events were similar among taxa. Events during late ontogeny, following meiosis in the anthers, had a direct effect on floral architecture and form at anthesis. Some of these events included curvature and rotation of filaments that repositioned the anthers inside the corolla, differential elongation between the adaxial and abaxial walls of the corolla, and growth of the style. Variation in position of the anthers relative to the stigma, and lengths of upper and lower corolla throats are hypothesised to have a direct effect on floral function. |
