A bulb is a specialized underground organ consisting of a short, fleshy, usually vertical stem axis (basal plate) bearing at the top a growing point or a flower bud enclosed by thick, fleshy scales. There are two types of bulbs: the tunicate or laminate type represented by the daffodil and tulip, and the non-tunicate or scaly type represented by the lily. Small bulbs called bulblets form at the base of the mother bulb and, with some lilies, along the underground stem. Some plants also produce aerial bulbs called bulbils.
A corm is the swollen base of a stem axis enclosed by dry, scale-like leaves. Examples include crocus and gladiolus. In contrast to a true bulb, a corm is a solid stem structure with distinct nodes and internodes. Small corms produced around the base of the old corm are called cormels.
A tuber is a modified stem structure that develops on underground stems. Examples include Irish potato and caladium. A few plants produce small aerial tubers known as tubercles.
Some sources make a further distinction among tubers, referring to structures that arise primarily from enlarged stem tissue as tuberous stems. These structures, in tuberous begonia and gloxinia for example, develop at the soil surface.
Certain species of herbaceous, perennials such as sweet potato and dahlia produce thickened underground roots. These structures are called tuberous roots (fat roots or fleshy roots) and have the same external and internal structure as normal roots.
A rhizome is a specialized stem structure in which the main stem of the plant grows horizontally at or just below the soil surface. Examples include iris, canna, and lily-of-the-valley. Rhizomes bear the same internal and external structure as true stems.
A corm is the swollen base of a stem axis enclosed by dry, scale-like leaves. Examples include crocus and gladiolus. In contrast to a true bulb, a corm is a solid stem structure with distinct nodes and internodes. Small corms produced around the base of the old corm are called cormels.
A tuber is a modified stem structure that develops on underground stems. Examples include Irish potato and caladium. A few plants produce small aerial tubers known as tubercles.
Some sources make a further distinction among tubers, referring to structures that arise primarily from enlarged stem tissue as tuberous stems. These structures, in tuberous begonia and gloxinia for example, develop at the soil surface.
Certain species of herbaceous, perennials such as sweet potato and dahlia produce thickened underground roots. These structures are called tuberous roots (fat roots or fleshy roots) and have the same external and internal structure as normal roots.
A rhizome is a specialized stem structure in which the main stem of the plant grows horizontally at or just below the soil surface. Examples include iris, canna, and lily-of-the-valley. Rhizomes bear the same internal and external structure as true stems.
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