I am stumped by this one, though I do know that plants can look more of less vivid in their coloration depending on light conditions (e.g., gold-leaf plants are yellower in a little more sun and greeny-yellow in a little more shade) and other factors (including soil chemistry in some cases, e.g. moptop hydrangeas). But the stems going from black to not? Hmmm…. I think we need a consult with a fern expert…it’s on my to-do list. Sorry not to know right off the bat, but that’s why I love these forums: We can all learn together. Anybody got any brilliant thoughts on this one?