Corn lilies and one-eyed sheep

One of the most abundant plants in the Crested Butte area is Veratrum californicum, also known as false skunk cabbage, corn lily, or “that plant that people from the Rocky Mountain Biological Laboratory wear in the 4th of July parade.”  This year we have the unusual opportunity to see an abundant display of their flower stalks, competing with those of the monument plant, Frasera speciosa, for the attention of photographers and pollinators. 

At a distance, it might be possible to confuse these two flowering plants, as both put up a conspicuous tall flower stalk of light-colored flowers, although Veratrum flowers a few weeks after the monument plants start flowering. But upon closer inspection it's easy to tell the two apart. Frasera plants have large flowers scattered along almost the entire length of the plant, while Veratrum inflorescences start at the top of a three-foot tall stalk bearing large leaves that somewhat resemble corn leaves, and are usually found in large, dense stands. The Veratrum flower stalks grow another couple of feet above the height of non-flowering plants, and bear thousands of small flowers.

Individual Veratrum plants have roots that are about 25-30 years old (they have growth rings on the roots), but the plants are much older than that because the root is growing forward (about a quarter inch a year) on one end and decaying on the other. When a plant flowers, the root can produce one to five new shoots, so the plants are reproducing clonally in the same year in which they reproduce sexually. After 25-30 years the root will grow past the point where the shoots were originally connected during a flowering year. Thus, even though they are no longer attached, many neighboring plants may be genetically identical clones. Some of these clones are quite large and at their slow growth rate could be several hundred years old, and perhaps older.  

Flies are probably the primary pollinators of the flowers, which are not popular with bees. The floral scent of a related species has been described as “latex and raw liver”, and the nectar may be toxic to some bees. The numerous seeds are dispersed by wind, but I’ve also seen them on the backs of cattle and deer as they walk past the tall stalks that are dropping seeds at the end of the summer. 

Veratrum looks like a lush, green plant, but it is not an attractive food for grazing insects or mammals. The leaves contain chemicals that confer protection from herbivores. The potency of these alkaloids is demonstrated by the fact that if a pregnant sheep eats Veratrum on the 18th day of her pregnancy, the lamb that results is born cyclopic (with a single eye in its forehead, like the Cyclops of Greek mythology). It took USDA biologists in Utah quite a while to figure out that link. Goats and calves born to mothers who have eaten Veratrum also exhibit a variety of birth defects.  A book on edible plants of the Rocky Mountains also claims that Native Americans knew about the toxicity of Veratrum and ate it to die by suicide. 

Flowering is relatively uncommon for Veratrum plants, but occasionally they produce spectacular displays. Since 1984 I’ve been studying the abundance of flowering in the vicinity of the RMBL. There have only been eight years with large numbers of flowering plants in the 42 years since then, and the last big flowering events were in 2017 and 2021. I don’t think this year’s flowering will be as abundant as those years, but in some areas there are lots of plants opening flowers now.

During the last big flowering event some of us at RMBL noticed that some flower stalks had withered tops that often bent over. By cutting into those stalks we found they were full of fly larvae. It appears that the flies are an undescribed species that hasn’t yet been given a name, and may be a specialist on Veratrum. A fly taxonomist is now working on assigning a species name. The sporadic flowering pattern may help to keep the fly populations lower.

A RMBL scientist who worked with me in 2013 did an analysis that suggests that cool summers are a trigger that sets up flowering that occurs two years later. The plants initiate (“preform”) both leaves and flower stalks two years ahead of when we see them above ground. If her model is correct, the ongoing climate change may mean that flowering will happen less frequently, depriving the plants of opportunities for both sexual and clonal reproduction. This could be another local wildflower that will become less common in the future, as the climate warms.

This is another example of the long-term research projects conducted in Gothic by RMBL scientists. Stop by the visitor center if you’d like to learn more.

David Inouye has worked at RMBL since 1971, and spends winters in the North Fork Valley near Paonia.