Today’s photograph was from the third week of May this past year, from a sidetrip to the Gasquet Darlingtonia Botanical Trail in California (not to be confused with the one near Florence, Oregon). I had hoped to see a particular species of Trillium there, but struck out again. Still, the wedgeleaf violets (cuneate = “like a wedge”) were out and in a convenient place to photograph, so I spent some time with them.
Viola cuneata is found only in northwestern California and southwestern Oregon. It is often associated with serpentine soils (a serpentinophyte), but it is not exclusive to these difficult growing environments. Studies have shown that it is able to accumulate high amounts of nickel in its tissues (up to 664 µg/g) without any apparent adverse effects (see Reeves, RD et al. 1983. Accumulation of Nickel and Zinc by Western North American Genera Containing Serpentine-Tolerant Species Am. J. Bot.. 70(9):1297-1303). Other nickel-tolerant species, such as Thlaspi montanum are hyperaccumulators of nickel (>1000 µg/g), and it has been shown that this is effective in producing tissue toxic enough to kill feeding insects (see Boyd, RS and SN Martens. 2004. Nickel Hyperaccumulated by Thlaspi montanum var. montanum Is Acutely Toxic to an Insect Herbivore. Oikos. 70(1):21-25).