Fig. 1

Pennycress nectary structure and nectar presentation. a Whole pennycress flower. b Two nectar droplets (arrowheads) cradled by petals on either side of a short stamen (SS); Pe = petal. c Two pennycress nectaries located at the base of long stamens, arrowheads point to tips of nectaries. LS = long stamen, C = carpel, PI = petal insertion site (outlined with dashed line). This image was created via confocal microscopy and a z-stack compilation of 12 images. d Nectaries (arrowheads) from a Stage 15 flower stained with iodine/potassium iodide. The darkly-staining punctate structures are stomates, which are the sites of nectar secretion. e Confocal image of nectary tip with stomates outlined