Nodes are one of the most magical parts of plant physiology. They are points along the plant stem where new lateral shoots (either stems, leaves, or flowers) emerge. Lateral shoots refer to any horizontal growth on the plant. It excludes the vertical growth that happens at the very top of the plant.
The spaces in-between the nodes are called 'inter-nodes'. Stems, leaves, and flowers only ever emerge out of a node, never from an inter-node.
If necessary, and given the right conditions, nodes are also able to produce roots The technical term to describe this type of root is 'adventitious'. It refers to any roots that grow from non-root parts of the plant. This is why stems cuttings for propagation must be severed just below a node. If the stem is cut along an internode, the stem cannot produce new roots and become an independent plant.
What are basal nodes?
Basal nodes are simply nodes located at the very bottom of plant stems. They are located just below or just above the soil.
What do nodes look like?
Many gardening guides instruct you to snip stems below a node for cuttings without describing what they actually look like. Even beginner's guides gloss over how to locate nodes.
But finding nodes is not all that easy. All plants have them but they look very different on different species. Some plants have very visible nodes while others are trickier to locate. With practice, you'll be able to spot nodes easily but starting without guidance is a challenge.
As a general guide, nodes look like joints dividing the stem into sections. Sometimes, nodes appear as indented rings that occur at roughly regular intervals along stems (portulacaria afra). They may show up as pale raised rings around the stem (monstera). Alternatively, the node may be dark rings (tradescantia, begonia). On these plants, the stem might change angle at each node. You will usually see leaves already growing out of nodes.
Plants with very thin stems have very small nodes. These can be easy to miss so you might need a magnifying glass to find them. On the string of hearts, which have very stringy and trailing stems, nodes look like tiny knots.
Here are some examples of nodes on various plants to get you started.
Hoya is a very diverse genus of flowering plants. It contains 200-300 species. They vary a lot in appearance, from their leaves to their nodes.
The photo above shows one node on a hoya carnosa stem. The hoya carnosa is the most common hoya species and you'll find them in pretty much any garden center. You can see two leaf-less bumps at the top left and right of the node. These buds may eventually produce new leaves.
Fern stems emerge from nodes in the underground rhizomes. Emmy LYF https://commons.wikimedia.org/w/index.php?search=rhizome+fern+&title=Special:MediaSearch&go=Go&type=image
Ferns are a very primitive plant. They emerged on earth long before plants evolved flowers as a reproductive feature. Ferns do not have flowers or seeds and instead reproduce by releasing spores.
Another difference between ferns and flowering plants is that ferns don't have roots. Instead, they are anchored in the ground by rhizomes. Although rhizomes look like roots, they are actually a special type of stem that grows underground.
These rhizomes, like above-ground stems, feature nodes. This is why you can't propagate ferns using their stems - they don't have nodes and can't grow new roots once severed from the main plant. Ferns are propagated by dividing them at their rhizomes. Once the divided section of the plant is placed into a propagating medium, it will put out new rhizomes.
Each set of spines on this Echinopsis Candicans is growing out of an areole William Warby https://en.wikipedia.org/wiki/Cactus#/media/File:Echinopsis_candicans_(3).jpg
Cacti nodes are special. They have a unique feature called areoles where nodes are packed very closely together without internodes separating them. It's as though the entire stem has shrunk into a very small space. You can spot the areoles by seeing where spines or flowers are emerging from the cactus.
Monstera nodes are representative of a great many tropical plant nodes. They look like joints segmenting the stem and are indicated by a thin line where it appears two stem sections overlap.
There are three nodes in this photo. An aerial root (the protruding growth in the center that is touching the moss pole) is growing out of one of them. The monstera has branched into two stems at this node.
Earlier, we said that cactus have special features called areoles where nodes are closely packed together. As a cactus, the rhipsalsis has areoles but they look very similar to nodes on non-cactus plants. They look like little joints segmenting the stems. They are quite small as the stems are so thin but show up darker and narrower than the rest of the stem.