Ilex opaca
Dendrology at Virginia Tech

Ilex mitis
Ilex mitis
African Pollen Databse

Ilex opaca

Ilex and Nemopanthus pollen is prolate and tricolporate with distinctive clavate sculpturing. The individual clavae (clubs) are irregular in size and shape, and are large in comparison to the grain. Some species of Ilex have uniform, small rods (baculae) next to the furrow in margo, while other species have scabrae (see SEM above) or are psilate. The "pore" is a thin area of the furrow that bridges the furrow area and may appear as a constriction in the equatorial area of the furrow. Holly (Ilex) is the most common genus worldwide, and the only one in western Europe, so as a pollen type, "Aquifoliaceae" practically means "Ilex". However, the genus Nemopanthus occurs in eastern North America, and it's pollen is similar to that of Ilex, although the sculpturing elements seem smaller in comparison to the size of the grain. The genus Phelline, a tropical genus sometimes placed in the Phellinaceae, has baculate - echinate scultpuring.

Ilex paraguensis
Ilex paraguensis
Botanical Online

The Aquifoliaceae is a cosmopolitan plant family of about 400 species in 3 genera. They are deciduous or evergreen trees or shrubs with spiny leaves and inconspicuous greenish-white flowers. The fruits are drupes. They are often cultivated as ornamentals, and the foliage is used for decoration during certain holidays, such as Roman Saturnalia. The most important species economically is mate (Ilex paraguensis). Native Americans made tea from the leaves of other species of Ilex as well.

Pollen light micrograph:
The prominent clavae are virtually diagnostic for Ilex, among medium sized (30-40µm) tricolporate grains.

Pollen scanning electron micrograph (SEM)
SEMs show the same features as light micrographis for Ilex.

Production and Dispersal:
This insect pollinated family has low production and poor dispersal, but the plants are so widespread that a few grains appear in many samples.

Good. The pattern formed by the clavae is distinctive even in poorly-preserved grains.

Fossil Occurrence:
Ilex-like pollen has been recovered from the late Cretaceous of Africa, Australia, and North America (Martin, 1977). It is found in Tertiary floras world-wide, in small numbers (Tschudy & Scott, 1969).

  • Lobreau-Callen, D. 1977. Les variations demensionelles du pollen du genre Ilex (Aquifoliaceae) et leurs repports avec le climat. Bull Soc. Bot. Fr. 122 Suppl. Cll. Palynol. 179-199.
  • Martin, H.A. 1977. The history of Ilex (Aquifoliaceae) with special reference to Australia: Evidence from pollen. Austr. J. BOt. 25: 655-673.
  • Punt, W. and Schmitz, M.B. 1981. Aquifoliaceae, The Northwest European Pollen Flora, 26. Elsevier.
  • Tschudy, R.H. and Scott, R.A. 1969. Aspects of palynology. Wiley Interscience.

Owen Davis 8/02