Urticaceae leaves with stinging trichomes were already present in latest early Eocene Okanogan Highlands, British Columbia, Canada

Abstract

The early Eocene Okanogan Highlands plant fossil sites in British Columbia, Canada and Washington, United States, contain a diverse assemblage of upland, warm temperate elements that provide a record of high-elevation floras including early members of several important families (Johnson, 1996; DeVore and Pigg, 2010; Greenwood et al., 2016). These floras, including One Mile Creek, Thomas Ranch, McAbee, Falkland, and Quilchena in British Columbia, Canada and in Republic, Washington occur in a series of lacustrine basins formed as down-dropped crustal blocks associated with volcanism. Although there is no exact modern analogue, we have suggested that the African Rift Valley and associated volcanic peaks are perhaps among the most appropriate, as a high-elevation, forested setting, populated with large herbivorous mammals and associated with volcanics (DeVore and Pigg, 2016). Well represented in the Okanogan Highlands floras are some of the oldest known fossils of Betulaceae, Rosaceae, Ulmaceae, and other families that today are predominately distributed in temperate regions of the northern hemisphere (Johnson, 1996). While studying

Uncover Itchy Leaves Ethnomedicine Usage: A Preliminary Study on Characterization and Bioactivity of Laportea Spp

“…Trichomes of the family of Urticacae easily fall off by touch; and have a sharp shape like syringes. 27 Syringes can penetrate the skin and release irritants. 28 In L. decumana the presence of more dense and dense trichomes are located on the leaf surface but easily detached, biomineralized, and less sharp in contrast to L. stimulans trichomes, which are rare on the leaf surface but have a more muscular shape and are attached to the leaf base which can penetrate the skin and provide more pungent irritant.…”