Douglas Justice's blog for November - November 2018 in the Garden | UBC Botanical Garden - is all about rhododendron leaves, and there are several very good photos there to illustrate his descriptions. I just found a few of the species he mentioned, but I photographed a ton of others I came across while I was looking. I'll start with ones in the blog. Douglas wrote a lot about the fragrance of Rhododendron cinnabarinum subsp. xanthocodon Concatenans Group. He added that "the flowers aren't half bad either, but you'll have to wait for sprint for those." Ha! It's not covered in flowers, but there were a few! The fragrance wasn't half bad either. I am pretty sure this is Rhododendron micranthum, though I think I just imagined that I detected the spicy aroma. Another included for its spicy aroma is Rhododendron wasonii. The collections page on Garden Explorer, at Rhododendron wasonii | UBC Botanical Garden, includes a photo that clearly demonstrates the indumentum coloured ivory or brown. My photos show some lighter indumentum and mostly brown.
I didn't get to R. bureavii this week (featured in the blog), but I have posted it twice previously - a couple of photos are in this 2013 thread. Here is a pretty good stand-in - Rhododendron argyrophyllum subsp. argyrophyllum. I thought all that low growth was (were?) pruned branches, but no, they're all attached to the ground. Here is Rhododendron yakushimanum, according to the label; this seems to be a synonym for Rhododendron degronianum subsp. yakushimanum (link goes to the Collections page on Garden Explorer). This one is near the pond in the north garden. The tag was clearly affixed to this plant, saying Rhododendron 'Scarlet Runner'. I've been looking things up to make sure I haven't got something very wrong, but you should see what comes up when you query this - every photo looks nothing like any other photo, and none looks quite like this; and of course there are a lot of beans. The collections page shows it as Rhododendron forrestii 'Scarlet Runner', so I tried that; still it's not all that convincing. Nice plant, though.
Here are two of the same species, different subspecies. Rhododendron calostrotum subsp. keleticum. And Rhododendron calostrotum subsp. riparium.
This might have been my favourite: Rhododendron linearifolium, so unusual-looking for a rhody. Others with nice hairs are Rhododendron sp. aff. spiciferum and Rhododendron taiwanalpinum.