 Some forms of the species have pink instead of white petals , while others with extra petals , also called " double " forms , are naturally quite common in the species , and these are especially popular with trillium gardeners . In fact , the species is the most popular of its genus in cultivation , which has led to conservation concerns due to the majority of commercially available plants being collected from the wild . A few regional governments in Canada and the United States have declared the plant vulnerable as a result . 
