Introduction to the Aquifoliaceae

The Hollies

The Aquifoliaceae are a group of about 400 species of primitive asterid flowering plants. Nearly all of these species belong to the genus Ilex, commonly known as the hollies. Most are evergreen trees or shrubs, though there are deciduous species that lose their leaves seasonally. Most Americans and Europeans are familiar with the spiny-leaved species Ilex aquifolium (English holly) or Ilex opaca (American holly), but it is actually uncommon for hollies to produce spines on their leaves.

The Hollies : Above at left, the "berries" of Ilex verticillata. The bright red fruits attract birds, who then disperse the seeds. At lower left, male flowers of I. verticillata viewed under magnification. The tiny white flowers are often overlooked. At right, Ilex opaca, the American holly. Most species of holly are shrubs or small trees. (Click on any of the pictures above for a larger image).

Most hollies are pollinated by insects, usually bees. The flowers typically produce either pollen or seeds, but not both, and these usually occur on separate plants. The greenish or white flowers are produced in small clusters and are not often noticed, though the fruits which mature from the flowers are noticeable and often bright red. These bright red "berries" and glossy leaves of some holly species has made them popular ornamental trees. Native peoples of North and South America have been known to brew highly caffeinated teas from some species, such as yerba maté.

Fossil pollen from the genus Ilex (holly) is highly distinctive and easy to recognize in the fossil record. The oldest such pollen comes from the earliest Upper Cretaceous of southeastern Australia, though Cretaceous age holly pollen has also been found in the nations of Gabon and Egypt in Africa, and from California.

By the Paleocene pollen from this group is known from South America and Europe as well, making the Aquifoliaceae a very widely distributed group at that time. The group is still common, and grows on every continent except Antarctica. Most species occur in the tropics, and the group is known for tolerating acidic soils.

Jan Muller. 1981. Fossil pollen records of extant angiosperms. The Botanical Review 47(1):1-142.

Images of Ilex courtesy the University of Wisconsin and used with permission.