On the large, vertical block of relief, Niankhwadjet inhales the scent of a lily (aka 'lotus').
Elements from the False Door in the Chapel of Mery's Mastaba
First half of Dynasty 4 (2575-2520 B.C.)
From Saqqara, Limestone
I hope on a return trip to get a decent photo of this, meanwhile, here is one at Flicker)

Come 2012, and a return trip, I still fumbled the large view, but at least I have a decent detail!

The information accompanying the relief says the scent of a lotus is associated with rebirth because the flower opens each morning for the sun. Bridget McDermott in Decoding Egyptian Hieroglyphs informs us further:

"The lotus had an important symbolic role in religious life. The blue lotus, which opens with the first rays of the sun, and the white lotus, which opens only at night, were associated with the sun and moon, and the opposing forces of light and dark...The lotus became a symbol of rebirth after death" and is "also linked to fertility and was a sexual symbol."

But as I recall reading in the KMT magazine, 'lotus' is really a misnomer, the flower is really a water lily.