The leaves of sympodial orchids are produced from the pseudobulb. There may be one or several. In cymbidiums, a number of long, narrow leaves come from the basal sheaths that cover the pseudobulb, and fall from the plant at a separation line that prevents any damage when the leaf is shed.

Cattleyas produce just one or two broad, semi-rigid leaves from the apex of the pseudobulbs. Leaves vary considerably in colour from a light mid-green to dark grey-green. Some paphiopedilums and phalaenopsis are mottled with light and dark green shades. Not all sympodial orchids produce pseudobulbs. The paphiopedilums and phragmipediums, for example, form fans of leaves from a basal rhizome. Monopodial orchids have a single vertical rhizome from which pairs of leaves grow at right angles. Vandas and phalaenopsis are the best examples of monopodial orchids in cultivation.

The tips of orchid roots are extremely vulnerable to damage and can be easily broken when they are outside the pot.

Pseudobulbs are the longest-living part of the plant and will exist in a dormant state long after the leaves have been shed. Leafless pseudobulbs are known as back bulbs. In evergreen types, such as cymbidiums, a healthy plant consists of more pseudobulbs in leaf than out of leaf. With the deciduous types, such as lycastes, a cluster of leafless pseudobulbs with only the leading one in leaf is normal.

Pseudobulbs have evolved into an unlimited range of shapes and sizes, from long, thin, pencil shapes to rounded or even flattened structures. They may be no larger than a pea, round and shiny, and delicious to look at when newly formed, as in the smaller coelogynes and bulbophyllums. By contrast, they may be the size of a tennis ball, as in the case of some cymbidiums. In cattleyas and allied genera, they become tall and clubshaped, swelling out from a narrow base adjoining the stout rhizome, while the one or two leaves are formed at the top.

Aim lac rhizome and seldom have nett law underground. Many orchids :Ticaosynthesize through the roots, n Mme examples there are a tii small epiphytic species that wine :become totally leafless, relying apon a bundle of thick roots to eritibe necessary chlorophyll. The soots of some orchids are also ammarb.ranractive; in phalaenopsis they ameniram white when outside the pot.

The purpose of this is not fully understood, but it may be that they are a protection from insects or a means of preventing water lying on the foliage, which could be detrimental on cold nights. Other monopodials, including vandas, have leaf tips that are serrated; these enable the plant to dispose of any excess moisture taken up through the roots.

The glow of light at the end of this hollow pseudobulb indicates the small hole at the bottom of the structure. In the wild, these orchids are infested with huge colonies of ants which live inside the hollow pseudobulb. The ant has a comfortable home, and the plant remains untroubled by parasites.