Before I get into the critique, I figure it might make sense to address your question. There's two questions there, but in truth they're one and the same. Where do you draw the line between construction and texture, and is there a good method for approaching capturing things that are too numerous?

The line between construction and texture is a bit blurry, but the baseline we can focus on is what our overall goal here is. Our aim is to communicate information to the viewer. That information pertains to the objects we're drawing. Through construction, we convey all the viewer needs to know to understand how they could ostensibly manipulate the object in space. Through texture, we convey what they need to know to understand how it might feel to run their fingers over the object's various surfaces.

That said, both constructional techniques and textural techniques are separated by a threshold that can be moved to suit our purposes - depending on the context, or our own goals for a drawing, there may be situations where we'd draw leaves individually with construction, and situations where we'd draw a treetop with uncountable leaves as an implied texture made up of shadow shapes instead. Another factor that comes into play there is similar to the difference between when we say "many" vs "much" in English. We say "many" when the amount is countable - so for the flower where you had placed that note, arguably while there are quite a few leaves, it'd still be a countable number, and therefore I'd argue that in that situation, we'd still construct each and every one. Same thing goes for the potato plant demo from the lesson. But when we talk about how "much", it's an uncountable quantity. Similarly if we were looking at the leaves in a treetop, it'd be unreasonable to count all of them, and therefore you could assume that drawing each one would similarly be unreasonable. So instead implying their presence through shadow shapes would be a more successful tactic, and would also result in a much less visually noisy result.

ANYWAY, onto the critique. Starting with your arrows, these are flowing quite nicely through space. In some of these you're doing a good job of capturing the effects of the foreshortening of the negative space between the zigzagging sections, but in some others you keep the spacing a little more regular. This is what I'm referring to - make sure you continue to keep it in mind for all your arrows.

Moving onto your leaves, you definitely carry the same kind of confidence and fluidity from your arrows over into this, and it does a good job of nailing down not only how the leaves exist in space, but how they move through the space they occupy as well. That said, I do think that your approach here is decidedly loose, relative to how I want you to be tackling drawing within this course, at least in a number of cases.

Construction is all about creating really strong, specific relationships between the different phases of construction. Your marks are definitely drawn very confidently, which is great, but there needs to be an amount of control behind them. We generally achieve this by using the ghosting method. You can also avoid overshooting by getting in the habit of lifting your pen off the page when you hit your end point, instead of trying to slow to a stop.

When dealing with complex leaf structures, we start off with a basic leaf structure as you've done in most cases here. Then when we create the smaller "arms" of the leaf, we ensure that our flow lines extend all the way to the outer edge of the bigger leaf shape. Not farther, not some arbitrary distance from it. Then each smaller leaf's edges are constructed from one end of these flow lines to the other. You can see this kind of specificity in this section and in this demo.

What we want to eliminate are loose, arbitrary distances. Those are the kinds of "loose" relationships that impede the sense of solidity and realism in our drawings.

Moving onto your branches, for the most part you've employed this technique well, except for one aspect - you've got a lot of arbitrary pinching/widening on your branches. Focus on keeping their widths even throughout the entire tube. That consistent width keeps the structure simple, which in turn makes it feel solid and three dimensional. The more complexity we introduce, the less solid it appears.

Moving onto your plant constructions, you're definitely headed in the right direction but there are a number of issues I'd like to draw your attention to. The point I raised earlier about your leaf/petal construction being looser than we'd like still stands here, although you're not particularly far off. I think it's just that what you were attempting to do is not entirely in line with what was asked.

Looking at this page, two things - first, make sure your petals end right on the end of the flow line. In general those flow lines appear to have been drawn a little haphazardly, not necessarily applying the ghosting method, so do be more careful with that. Secondly, draw each petal in its entirety. Don't cut off forms where they're overlapped by their neighbours. Having each form drawn completely allows us to better understand how they sit in space, and in turn how they relate to one another. Since every drawing within this course is an exercise in spatial reasoning, rather than an individual opportunity to draw something nice, this is particularly important.

Jumping down to this page, we again see more of those "loose" constructional relationships, but there's another issue I want to address. The way you're approaching this is that you draw a simple version of a given petal, and then draw another complete petal on top of it, replacing the line from the previous phase and making it rather moot. In construction, we don't replace one phase with the results of the next. Each phase builds upon the last one directly, and we only add new line segments where the previous one needs to be altered. You can see this concept conveyed in this demo, as well as in these notes I put on another student making the same mistake.

For this page, the constructions are reasonably well done (again, if a little loose) but always remember that texture is not decoration. It serves a purpose, as discussed at the beginning of this critique, to convey particular kinds of information. So always focus on that as your goal, rather than a general desire to make a drawing more detailed and visually interesting.

As this critique has gotten quite long and you do have a few things to work on in order to properly apply construction to your work, I'm going to stop here and assign some revisions. You'll find them listed below.