I've identified one or two things recently that seemed to be correct, so I have the nerve again to post this as if I know what it is. I've only seen Clethra barbinervis at UBCBG, and my photos of that show some red veins, so maybe this isn't right. But it's much taller (maybe four or five times my height) than C. alnifolia, which is the only other Clethra I know, and the inflorescences extend horizontally or droop, which also distinguishes it from that. This is in Stanley Park, on the rhododendron garden path.
