Introduction

Plants are so incredibly diverse in their morphology, that it wouldn’t surprise me if there were more descriptors in botany than in zoology, biochemistry and microbiology combined! (And that is truly saying something.)

Every minute detail of a plant has at least one word for it. By way of example, let’s describe a jujube leaf botanically — pull up this reference, and this page too for more terms, and follow along!

Shape and Arrangement

A leaf in botany is also known as a blade or a lamina. (two words right there!)

Below is a jujube fruiting branchlet, upperside (and can you see what looks like leafcutter bee activity?):

and underside:

At first glance it may be mistaken for a compound leaf, one in which the blade is divided into leaflets. (Jacaranda mimosifolia and ferns are examples with compound leaves.)
And (with reference to the morphology chart) a pinnate one specifically. (And an alternipinnate one at that.) 

But when budding/flowering, this is more clearly a branch (branchlet more accurately), as no leaf has buds or flowers along it like this:

So a jujube leaf is a simple leaf. Let’s zoom in:

The uppermost surface is on the left and the underside is on the right.

Again with reference to the chart, these leaves are arranged alternately along the fruiting branchlet — each leaf along a branch alternates in position from one side to the next, as opposed to an opposite arrangement, whereby leaves are arranged in pairs along a branch.

From this point on, descriptors can be open to interpretation, and one person’s description may clash with another. Adding qualifiers such as dimensions can help in some cases.

Also worth knowing is that there can be a lot of variation in leaf shape even on the same plant. For added complication (welcome to botany!), some species have juvenile foliage completely distinct from adult leaves. Brachychiton rupestris, the Queensland bottle tree, is a really good example of this — its juvenile leaves look like this, and its adult leaves look like this.

Thus the following is just my take, and you may or may not agree. But for what it’s worth:

A jujube leaf is very wide at the base (the bottom) and tapers to a blunt apex (the tip). To me the overall shape is ovate, but not quite. Partly because the tip tapers more to a point than ovate, and partly because the base is slightly cordate.

Therefore we could describe this leaf as being about 20 mm wide at the base, about 80 mm long, and 45 mm at its widest part a third of the length from the base’s edge.
It has an acute tip and a slightly cordate base.

Leaf Margin

‘Margin’ is another word for ‘edge’. And again this leaf doesn’t fit a neat little pigeonhole. The edges are toothed and not strongly pronounced, and somewhat serrate-crenate.

Venation

You may have to click on the leaf image immediately above to view at full size, but the venation is very clearly reticulate.

Hairs

We can go still further! Jujube leaves are glabrous (hairless) on both sides.