Urticaceae Pollen

Urticaceae, the nettle family, is a family of 53 genera with over 2,600 species. The family is widely distributed in tropical, subtropical, and temperate regions and includes herbaceous plants, shrubs, woody vines, and a few trees. The flowers are small and inconspicuous with both monoecious and dioecious species in the family. The leaves and stems in some members of the Urticaceae are covered with hollow trichomes (hairs) that contain various chemicals including histamine. When these are touched, the tip of the trichome breaks and the chemicals are injected into the skin, causing burning, itching, and swelling. For this reason, the Urticaceae is sometimes called the “stinging nettle" family. Seven species in the Urticaceae occur in Oklahoma, all of them are herbaceous plants. 

Pollen in the Urticaceae cannot be identified to genus level by microscopy. As a result, the pollen is only identified as Urticaceae pollen in air sample analysis. The pollen grains are small (10 to 15 µm in diameter) and triporate with a small and often inconspicuous oncus beneath each pore. The pollen grains are thin walled, faintly staining, and often appear partially collapsed in air samples. Urticaceae pollen occurs in our Tulsa air samples during spring, summer, and fall, reflecting different species within the family.