Grasses have a main stem with a sheath and leaves wrapping around the stem below. Their leaves have parallel veins. Growth pattern is alternate (leaves staggered on the stem) or basal.

Also called shrubs, plants in this category are woody and are usually multi-stemmed and less than 16 feet tall (with some exceptions). They have shallower roots than trees.

A twining or climbing plant with relatively long stems, vines grow on something, with tendrils. May have prominent flowers. Can be woody or herbaceous.

Often called "weeds," forbs usually have a non-woody stem (easily bent) and prominent flowers. They may be annual, biennial, or perennial. They can have single or multiple stems or grow in a basal pattern, meaning all growth comes from the base.

Stems of cacti are thick and succulent, sometimes forming pads. Leaves are reduced to spines and barbs and grouped in definite clusters on the stem. Different species have many differently colored flowers.

Trees are woody and have bark. They usually have a single trunk (with some exceptions) and taproots. Different species have different shapes and kinds of leaves, such as needles, evergreen leaves, or deciduous leaves.