Stem

The main supporting feature and central axis of a plant to which branches, leaves and flowers are joined, either directly or indirectly. Buds can also be present and from these can arise leaves and flowers. Plants can have one or more (multi-) stems and the main vegetative growth point for many plants is from the tip of a stem (and leaves), with this being called an apical meristem. For some plants, such as grasses, the main growing point is from the base of the plant (the stem base) and is called an intercalary meristem.

The stem contains ‘channels’ called xylem and phloem which, respectively, help transport water (with dissolved nutrients from the soil) and mostly dissolved organic products from photosynthesis around a plant.

A stem will usually have one or more nodes present, and the stem length between each node is the internode.

The size and shape of a stem are common throughout a species; some being short, thin and delicate stems as in grasses, slender low or ground hugging stems (e.g. Periwinkle (Vinca sp.) or Heather (Calluna sp. or Erica sp.)) to tall and wide girth stems (e.g. trees).

The height of a plant will depend upon the species as well as the growing and environmental conditions, and the age of a plant.

A couple of stem types which are often confused for roots are rhizomes (e.g. Flag Iris, Couch Grass, Strong Creeping Red Fescue) and stolons, which develop noticeable adventitious roots at the node (e.g. Creeping Buttercup, Creeping Bentgrass, Strawberry).

A stem can grow in different ways:
• If it grows upright, it is referred to as being erect.
• If it grows in an upwards direction, but not perpendicular to the ground, then this is referred to as ascending.
• If growth is low to the ground, being generally horizontal but with the ends of stems growing upwards, then this is referred to as decumbent.
• Where growth stays along the ground in a horizontal direction then this is referred to as procumbent growth.