Sarah Ward Homepage
Current Research Projects

Hybridization Between Invasive Toadflax Species
We are investigating hybridization between yellow toadflax (Linaria vulgaris) and Dalmatian toadflax (Linaria genistifolia subsp. dalmatica), two introduced species now invasive throughout the Intermountain West. Although the native European ranges of these two toadflaxes do not overlap, invasive populations of yellow and Dalmatian toadflax co-occur in many areas of the Rocky Mountains, and our research has confirmed that spontaneous hybridization is taking place between them. We are now investigating whether hybrid populations represent a greater invasive threat than the parent species.

Toadflax hybrids growing with the parent species in a common
garden experiment at Colorado State University, early July 2009.
In an ongoing collaboration with Dr. Sharlene Sing at Montana State University, we are also examining the feeding behavior on hybrid plants of two biocontrol agents (Brachypterolus pulicarius and Mecinus janthinus) that are currently released on yellow and Dalmatian toadflax. As each of these insects has a distinct preference for one or the other parent toadflax species, our goal is to find out whether both (or neither) of them will be effective on hybrid toadflax plants.
Inheritance of Glyphosate Resistance in Palmer Amaranth
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Glyphosate Resistant Palmer Amaranth |
Cross-pollinating Palmer Amaranth in the Greenhouse |


