Yes, the pot of lilies symbolises the Virgin Mary, whose skirts are visible on the right of the picture, as she sits enthroned. Which saint is offering the plant? It may be easier to identify it from stories about him, than by trusting the artist's botanical accuracy. Madonna lilies, then, and possibly something medicinal?
Thank you all. It is a picture of GAbriel announcing the birth of Christ to Mary. I have to analyze for a class.
The Duccio in Assisi? We're not supposed to help with homework, but consider what Gabriel might be offering Mary, as a peace offering? And grows in Italy?
Wrong painting, wrong city, but right idea about the peace offering, though. Usually Gabriel is offering the lilies, but not when the painting is for a altarpiece in Siena, and the lily is the symbol of an enemy. I think I've offered enough hints now, but if you actually need a straight answer I'll oblige.
I think it's OK and seems to be relevant, since it is a historic religious image. Let's keep this thread directed at the possible identity of plant being represented in the image.