Dichotomous Key for 4 Plants – Biol 190
A – Woody …………………………………………………….B
A1 – Herbaceous……………………………………………….C
B – Has needles……………………………………. Spruce
B1 – Does not have needles…………………………… Willow
C – Simple leaf, margin entire……………………………….. Willow (young stems)
C1 – Compound leaf………………………………………….. D
D – Leaves oddly pinnate compound …………………. Rockcress
D1 – Leaves palmate compound ……………………… Pasqueflower
This key is specifically designed for 4 specific pictures of plants and is not appropriate for use in any other situation.
Hi Denise! Here’s my attempt at using your key:
Plant 1:
A (Woody) > B (Has needles) > Spruce
Plant 2:
A’ (Herbaceous) > I thought this plant had simple, entire leaves from the image, but your key has it as a compound leaf. Hard for me to tell from the image! 🙁
Plant 3:
A’ (Herbaceous) > C’ (Compound leaf) (?) > D’ (Leaves palmate compound) > Pasqueflower
Note: Hard to tell if leaf is compound or is simple but deeply divided.
Plant 4:
A (Woody) > B’ (Does not have needles) > Willow
I really, really like that you included the possibility of somebody identifying the Salix sp. (plant 4) as either woody or herbaceous — I like when dichotomous keys are flexible enough to cover the possibility of the user being confused about a characteristic like that, since it is not extremely clear from the image alone. I saw other dichotomous keys identifying Plant 4 as either woody or herbaceous — I chose to leave that distinction out because I didn’t think it was clear, but I really love the way you chose to do it! 🙂
One difficulty was that I could not tell if the leaves of Plant 2 or Plant 3 were compound or not from the images — not your fault though, that’s just how it goes sometimes if I don’t have the plant right in front of me. I was confident to the genus level on plants 1, 3, and 4. I actually couldn’t tell what plant 2 was, but I noted it as having simple linear leaves in my key based on the image. For plant 3 (pasqueflower), the image made it difficult to see if the leaf was actually compound or just deeply divided — in my key, I listed it as having deeply divided leaves rather than compound leaves, but I’m not 100% confident either way.