Aroid is a common name for a large species of plants in the Araceae family. This family of plants is also often called Philodendron or Arum family. There are over 100 genera and 3,750 species of aroid plants, most of which are from the tropics, though some temperate species exist. Most of the tropical species evolved in the dim light of the rain forests, a feature that makes many aroid plants well suited as houseplants where low light levels tends to stress many sun-loving plants. Some members of the Araceae family are familiar houseplants while others are rare mysteries rarely found outside the rain forests or greenhouses.
Aroid plants often have lush, dark green and glossy leaves. The flowers are characterized by an erect spadix surrounded by a spathe. The spadix is a spike that is made up of multiple tiny flowers; it is surrounded by the spathe, a thick, often colored, petal-shaped sheath. Anthuriums, calla lilies, and peace lilies — all aroids — are common examples of this flower structure. The entire flower structure, including the actual flowers, the spadix and the spathe, is called an inflorescence.
One example of the strange members of this plant group is the titan arum. The spadix reaches a dramatic 10 feet (about 300 cm) tall. The spathe is maroon on the inside and, when fully open, extends out 3 to 4 feet (about 90 to 120 cm). The tiny flowers bloom in the thousands along the erect spadix, where they are pollinated by insects that are attracted to the smell of rotting flesh that emits from the inflorescence of the titan arum.
While the titan arum does not make an ideal houseplant both for its size and particularly unpleasant smell, many aroid plants are ideally suited for indoor growing. The deep green foliage is attractive year-round, even when the plants are not actively flowering, and the flowers appear periodically throughout the year, often in winter when other plants are dormant. Peace lilies and anthuriums are some of the most common and popular aroid houseplants, but others such as the dumb cane and Chinese evergreen, both of which have multi-colored, visually interesting foliage, are also well suited for indoor growing.
Many commonly found aroids require little care. Good drainage, some humidity, and the occasional fertilizing will keep these plants happy and flourishing, and because they do not require lots of light, they can add greenery to some of the darker rooms and offices. The flowers are simply pinched or clipped off when they fade, and browning or dying leaves are removed at the soil line periodically to keep the plants looking their best.