Bart O' Brien, of Rancho Santa Ana Botanic Garden, has suggested these: Where did the unknown Euphorbiaceae come from? Though I'm sure that there are numerous possibilities, two to explore further would be: Homalanthus populifolius or possibly Sapium sebiferum (though I don't recall ever seeing bracts in the new growth as in the photo).
The seed? came from Australia, where the plant is being used as a street tree. This image of "Omalanthus populifolis" from the Australian National Botanic Gardens looks very similar to the plant. Also, the description in the Malesian Euphorbiaceae is fairly close (including the prominent gland at the junction of the lamina base and petiole). I think it's either this or something very similar. The Queensland's Herbarium "Flora of Southeast Queensland" published in early 2003 suggests that the current proper name for this plant is Homolanthus nutans. I don't have access to the World Checklist and Bibliography of Euphorbiaceae to check. Commonly, this plant would be known as the "bleeding-heart tree" or "Queensland poplar". The leaves change colour to red before falling.
Identical to what is growing in my garden Thank you for the photos. These are the only photos I've found that look exactly like what has emerged in my garden in Los Angeles.
