Yellow violet

I've been having more fun with my Easy-Macro lens. I just can't seem to stop! Anyway, because of it I learned something new yesterday. I'd taken this photo of a tiny flower with it the day before:

Here's just a regular iPad photo to show what plant it came from:

Then yesterday morning, I was going to post them to Instagram and ask if anybody knew what that plant was. I tried looking it up as a weed, but I didn't find anything that really matched. So back outside I went to get another look (because I hadn't really paid much attention to the plants when taking the pics). Here are a couple more iPad shots (I should've taken the DSLR but wanted the pics handy for Instagram):

They are under some evergreens in our backyard. It was pretty windy then, so the leaves are blowing a lot in the picture below, but I took it for size comparison with the dandelions that you can see in the foreground:

While I was out there, it dawned on me that the plants sure looked like the purple violets I have in front of the house (the ones the woodchuck likes). I didn't know if there was such a thing as a yellow violet, but googling it found me plenty of photo proof that there certainly is! So that was the new thing I learned yesterday.

Yellow violet. Is that an oxymoron? I certainly think so! And really, why weren't they just called "yellows", if the violet ones are called violets??? ;-Þ