Post #743279 by Limbo Lizard on Tue, May 19, 2015 5:09 PM

If the drawing is accurate, I think you're looking for a more perfectly heart-shaped leaf than that nettle, and with less pronounced serrations.
One possibility is a species of trees, the Tilia, also called Linden, Basswood or "Lime" (but not to be confused with citrus). Here are leaves of the Small-leaved Lime (Tilia cordata), which are apparently edible:

Here is the leaf of the American Lime, or Basswood (Tulia americana), also edible:

Again, if the drawing is right, we may be looking for a leaf with a longer stem than these. Upon further reading, it seemed this tree would struggle in the warmth of much of California. So maybe a vine or tree more suited to California? But then I ran across references to 100+ year old specimens in California, after all.
(Source for the photos, above.)

"The rum's the thing..."

[ Edited by: Limbo Lizard 2015-05-19 17:46 ]