Orchid Family Facts - Part One

The orchid family is spread all around the world, ranging throughout the tropics, across moderate zones of both hemispheres, and even into the fringes of the Arctic. But as in any family, there are branches of the family tree.

The first branching separates the monopodial and sympodial groups. The monopodial, including the Vanda and Aerides, grow upward from a single point. They add leaves to the apex each year and the stem grows longer accordingly. Phalaenopsis orchids, though monopodial, are stemless, but they grow a pair of leaves from the characteristic crown annually. The word Monopodial is derived from Greek "mono-", one and "podial", "foot", in reference to the fact that monopodial plants have a single trunk or stem.

Orchids with monopodial growth often produce copious aerial roots that often hang down in long drapes and have green chlorophyll underneath the gray root coverings, which are used as additional photosynthetic organs. They do not have a rhizome (stem of a plant that is usually found underground, often sending out roots and shoots from its nodes. Rhizomes may also be referred to as creeping rootstalks, or rootstocks) or pseudobulbs so species adapted to dry periods have fleshy succulent leaves instead. Flowers generally come from the stem between the leaves.

The sympodial group, of which Cattleya, Laelia, and Coelogyne are notable examples, have pseudobulbs-- the individual "shoots" of a sympodial orchid which have a chunky base to hold water topped with leaves. Sometimes the pseudobulb is small and the leaves are long (as in Cymbidiums) and sometimes the pseudobulbs are long and the leaves are small (as in Dendrobiums).

The orchid bloom spikes usually come from where the outermost leaf meets the pseudobulb. At the base of sympodial orchids are small nodes that are called "leads". They may have one or more leads and from these will grow new pseudobulbs. The word Sympodial means "with conjoined feet".