Those are epiphytic orchids—air-plants, you know: they require no earth for their roots: they live on the air.
Among the plant-treasure from India, Australia and Malaya were large numbers of epiphytic orchids.
A plant that grows on another plant and depends on it for support but not food. Epiphytes get moisture and nutrients from the air or from small pools of water that collect on the host plant. Spanish moss and many orchids are epiphytes. Also called aerophyte, air plant.
epiphytic adjective (ěp'ə-fĭt'ĭk)