Here's why each of these terms applies:

* Appearance: This is a general term that describes how something looks to the observer.

* Form: This refers to the overall shape and structure of the plant, including its size, branching pattern, and arrangement of leaves.

* Morphology: This is a more scientific term that describes the internal and external structure of the plant, including its leaves, stems, roots, flowers, and fruits.

You can also use more specific terms to describe different aspects of a plant's appearance, such as:

* Color: The color of the leaves, flowers, and stems.

* Texture: The feel of the leaves, bark, and other parts of the plant.

* Pattern: The arrangement of leaves, flowers, or other parts of the plant.

* Symmetry: The balance and regularity of the plant's form.

Ultimately, the best term to use will depend on the context and the level of detail you want to convey.