Fig. 1
From: Evidence of a largely staminal origin for the Jaltomata calliantha (Solanaceae) floral corona
Emergence of the J. calliantha corona in late flower development. a–c Scanning electron micrographs of mid-stage flower buds, prior to a coronal outgrowth at the base of stamens. d Young stamen base with filament detached showing outgrowth of the corona. e Side view of d indicating outgrowth of the corona on the abaxial side of the stamen around the base of the gynoecium. f Scanning electron micrograph of a fully expanded and mature stamen base covered with trichomes. g Dehydrated mature flower with stamen filaments and most of the perianth removed to reveal the corona lobes and swollen stamen bases. h Close-up of the two-lobed corona between two stamen bases from g. i Close-up of the inner organs of open flowers showing five stamens emerging from green swollen bases that contact the gynoecium base on their adaxial side. Petals have been trimmed back to reveal five corona cups between the swollen stamen bases, on top of the petal bases, and adjacent to the gynoecium. Secretion of light-colored nectar into the corona cups begins shortly after flower anthesis. j–l Nectar becomes darker red as the flower ages, and pools in the slightly heart-shaped corona cups. sep sepal, pet petal, st stamen, stb stamen base, fil stamen filament, cor corona, gyn gynoecium. Scale bars = 100 µm for (a–f) and 1 mm for (g–l)