Pseudobulben

Pseudobulben, known in English as pseudobulbs, are swollen stems that function as water and nutrient storage organs in many orchids, particularly sympodial species. They are not true bulbs; rather, they are condensed portions of the plant’s stem that help the orchid survive periods of drought and variable moisture in its usually epiphytic habitat.

Morphology and growth patterns vary widely. A pseudobulb is typically a single, compact segment that may be bottle-shaped, ovoid, or cylindrical. One or more leaves are usually borne at the apex of each pseudobulb, though some species shed leaves seasonally. Pseudobulbs are often connected in a sequence along the plant’s rhizome or base, forming a chain-like growth habit characteristic of many genera such as Cattleya, Dendrobium, and Oncidium. In dry periods, the stored water in a pseudobulb helps sustain the plant between rains.

Function and adaptation are central to their presence. The primary role of pseudobulbs is to store water and, in many cases, photosynthate. They may also provide a degree of nutrient storage, enabling rapid growth when conditions improve. The surface of some pseudobulbs is photosynthetic, adding to the plant’s energy budget.

In cultivation, pseudobulbs are typically the main structural features handled during repotting. They should not be mechanically damaged, as rot can spread from compromised tissue. Care practices emphasize good drainage, intermediate to bright light, and a watering regime that aligns with the plant’s growth cycle: frequent watering during active growth and reduced watering during rest periods.