Butterfly weed, or orange milkweed or pleurisy-root (Asclepias tuberosa)
The ink painting is covered with notes about the plant's structure, especially the Fibonacci spiral that determines the placing of the leaves. It is on milkweeds that monarch butterflies feed and grow. Butterflyweed—one of the few truly orange wildflowers—is found in small colonies such as beside a wood; it spreads by underground tubers and so sometimes crops up as a "fairy ring".

Bloodroot
One of the earliest spring flowers in the Carolina mountains. Pushing up through leaf-litter and about to open.

Sweetgum twig
Sweetgums often extrude woody ribs through their bark, creating miniature Monument-Valley-like scenery.

Mexican leaf
Diagram of a curious leaf seen in a jungly part of my bicycle ride from Guadalajara to Puerto Vallarta.

Maple leaf stuck in a deck in South Carolina

Early-fallen maple leaf

Scarlet oak leaf or maybe a black oak
with voluptuously sculptured "sinuses" between the lobes

Mulberry leaf

Bramble leaf in late winter
with a bite taken out in the summer. Pencilled note says: "The scarlet advances each day at expense of the purple, covers leaf in 3 days"