When I photographed this wildflower in Idaho I identified it a Calochortus eurycarpus, White Mariposa Lily.   I now think that was an incorrect ID; I believe this is Calochortus bruneaunis – Bruneau Mariposa Lily.   Read on for an explanation of how I changed my mind…

Bruneau Mariposa Lily- Calochortus bruneaunis

“White Mariposa Lily” was the Native Plant of the Day a week or so back on USWildflowers.com.  I took that as an initiative to check out other Internet photos of this lovely wildflower.  In doing so, I decided I had been too lazy in my initial identification, and am hoping that this time I’ve done sufficient homework to get it right.

Here is my plant – a view of the entire blossom, and a closeup to show the interior better.   Compare those photos with this photo by Christopher L. Christie over at the Calphotos website of the Univerity of California, Berkeley.

Bruneau Mariposa Lily – Calochortus bruneaunis

Bruneau Mariposa Lily – Calochortus bruneaunis

Differences:

• C. eurycarpus is more likely to have pink tinting on the petals, and some photos I’ve seen have entirely pink petals.
• The hairs near the base of the petals in C. eurycarpus are significantly longer than those of C. bruneaunis.  This was one of the key features that had me rethinking my identification.  You may even need to click on the photo on the right to get a larger image to see the hairs in my photo.
• The sepals of C. eurycarpus extend well beyond the petals; those of C. bruneaunis are shorter than the petals.  I rationalized this by saying the bloom must be past its peak.
• USDA Plants Database does not list C. eurycarpus in Canyon County, but does list it in Ada County.  C. bruneaunis, on the other hand, is listed in Canyon County but not in Ada County.  I thought I was still in Ada County, but was actually over in Canyon County.  While the USDA Plants Database county listing is not definitive, that should have led me to dig deeper on the initial identification.  I should have done better research on my location.  Bruneau Mariposa Lily is found in California, Idaho, Montana, Nevada, Oregon, and Utah.

I hope I’ve done my due diligence this time and got the identification right – Bruneau Mariposa Lily.  I took some shortcuts and got it wrong the first time. Wildflower identification isn’t easy, but it is rewarding, and worth doing right.

I would certainly appreciate vetting from the Internet community on this and all of my identifications – please leave a comment or send me an email (identification[at]uswildflowers.com) if you find an identification you question.