Cattleya orchids are one species of tropical orchids belonging to the very large orchid plant family that contains over 35,000 other species. Cattleyas are an epiphytic form of orchid, meaning that they grow not in soil, but attached to trees or surfaces in the wild and in coarse bark and charcoal when potted. The slim white aerial roots absorb moisture and dissolved nutrients to sustain the plant. Cattleyas can be identified by their bloom form and often by their foliage and pseudo-bulbs when not in bloom.
Identify a cattleya by its bloom, which will be in cool-tone hues from white to light orchid to deep violet pink. The large curvilinear petals have ruffled edges and are arranged in roughly a star shape. There is a central top petal and four side petals with two facing up and two facing out or down. The petals encircle a prominent trumpet-shaped throat. The petals and throat can be the same color or contrast in color.
Look at the green plant foliage for short thick, ovoid, strap-like foliage that is several inches long. The stems of the plant are somewhat segmented, resembling bamboo. Cattleyas produce multiple pseudobulbs that are green and in roughly a bloated surfboard shape from which the leaves emanate.
Orchids with multiple pseudobulbs and leaves are mature plants. Dendrobium orchids also have this same general pseudobulb, segmented stem and leaf arrangement. Cattleya stems, however, are much shorter and the leaves wider and rounder in shape than those of the dendrobium.
Seek to see what the potting medium is, and what the roots are growing in as a clue to the species of orchid you have. If you see soil in the medium, it is likely you have a species of terrestrial orchid. If there is no soil in the pot but just coarse chunk bark, charcoal and perlite, it is an epiphytic orchid. Cattleya roots are thin and cling to, or wrap around, the planting medium in keeping with its tree growing origins.