Sorry for taking too much cotton! Been very busy with university so couldn't take too much time to do critiques.

Arrows

They flow pretty nicely and they're pretty good in general. To improve them, you can try making the gaps between arrows and the arrows themselves grow bigger more exponentially.

Leaves

When adding texture, do it the same way as in lesson 2, focus on, and draw only cast shadows.

The leaves themselves look good, though the detail kinda hides the construction, so I might be missing something.

Branches

You seem to be handling them quite well. Though you have some where you seem to rush them a bit. Don't forget to go back to your initial ellipses if your marks go off. Do one part of the branch as the time not to to lose accuracy.

Plant constructions

You're doing a pretty good job, and your plants look pretty good and solid in general, but I want to comment in a few things you can approach better.

1.Don't use substractive construction as you did here. If you can use additive construction instead of substractive, then do it. It's way easier to think about 3d forms when doing additive, because when working substractively it's very easy to cut them as if they were 2d shapes, which is what you did. When working substractively it's not enough to just cut into the forms in 2d. You need to work as if your pen was a scalpel, cutting your forms in 3d.

2.I can see you have a tendency to go over the "finished drawing lines" with lines to make it more important than the constructional parts. Avoid this. In drawabox exercises, constructional lines and the lines that viewer sees, the finished ones have the same importance. You can add lineweight to clarify overlaps, or to make a certain part pop up because of some reason, but don't do it over the whole drawing just because it's part of a finished drawing.

Noted a few things here, hopefully they'll help clarifying some points a bit