A tuber is a swollen underground stem modified for food storage with often with nodes and buds along the surface.
Tubers are similar to corms except that tubers usually do not have a papery tunic.
Spring beauty Claytonia
Potato (Solanum tuberosum) is the most commonly thought of tuber producing plant, but other include Caladium, Anemone, Cucurma, and Phlomis.
Tubers often are produced at the ends of stolons.
There is also fern called Nephrolepis tuberosa that produces a tuber with a similar appearance to potato.
An interesting linear tuber is found in Gloriosa.
New growth is initiated from the tips of the tuber.
New tuber forming at the base of the shoot.
In general, tubers can be propagated from seed or from division of the tuber. When dividing the tuber, several buds are usually included in each division and division is performed while the tuber is dormant.
In Caladium, tubers are divided into sections containing two or more nodes and planted in the spring. Tubers are harvested from plants in November and dried for several weeks.
These are stored under cool refrigeration (60°F) until they are sold in the spring.
Sandersonia is an example of a cutflower crop grown from a tuber. It is propagated from seed and the tuber is increased to flowering size after one growing season.
Seed harvest begins with removing the fruit before the seeds are shed. The fruits are capsules that are allowed to dry under protection from the rain in a greenhouse.
When the fruits are dry, they are run through a seed extraction machine the separates the seeds from the fruit.
Seedlings are grown through the summer in raised beds in a loose organic medium. The raised beds make tuber harvest easier in the fall. The foliage was removed and any fruit capsules were collected for seed harvest.
After harvest, the tubers are sorted by both size and shape. Large size tubers will produce plants that will flower and are sold to cut flower growers.
Tubers in Sandersonia are fork-shaped with two arms developing from a central point where the foliage arose.
Next year's growth initiates from the tips of the arms.
In some cases, secondary tubers can also form at the tips.
These are called marbles or buttons and can be used for propagation.
Marble tubers will be planted back for a second season of growth to produce larger "seed strike" tubers.