I am a complete newby at this so please forgive me for this silly question.
I know that these two leaves are dandelion leaves, but why are they so different? They were growing right next to each other (in separate plants). Are they a different species or do dandelion leaves just vary that much?
Dandelion leaves are quite variable in shape, depending on the size of the plant, growing conditions, etc,
one of those leaves could be a chicory. they look like dandelion when they're young.
There's several hundred species in the genus Taraxacum