I have long been interested in seeing for myself the comparatively rare Snow Trillium. I know that it has been found in only six WV counties and most habitats seem to be in difficult to reach areas. So when an opportunity presented itself to see this species in a walk sponsored by the Botanical Society of Western Pennsylvania, I jumped at the opportunity. The destination was in nearby Westmoreland County near Greensburg PA. The rally point looked very ordinary as did the trail, an old abandoned rail line through a rather thin, young woods. Different however was the nature of the soil - it was almost like a shale barren, not really rich in humus or ground cover. At first, the blooming plants were easy to miss because of their small size and the lack of contrast with green from other plants, but soon there was one or two and then whole colonies of the diminutive blooms. They looked pretty much like other trilliums except for their small size and the color of the leaves which seemed to be covered with a light, almost lavender pruina.
Snow Trillium does not grow in leaf mold, humus, or near much plant competition. It prefers south-facing, limey, sandy gravel, crevices in limestone, or calcareous mineral soil instead. Trillium nivale occurs primarily at the southern edge of Pleistocene glaciation.
Mature plants produce a single flower on a short stalk about 2" long that is straight or arching. The flower, unlike most other species of Trillium, is much, much smaller - only 2" across. The entire plant seldom exceeds 4" in height. The petals are oval-ovate and often slightly undulate along their margins. The recurved sepals are lanceolate and often slightly reddish or yellowish on the outer surface. Other than their unique and rare habitat, The blooming period occurs during early to mid-spring when few are out in the woods tramping around. Indeed, in our area everything has been under snow until quite recently. Flowering lasts only about 2 weeks.
But perhaps what sets these plants apart from other plants is their remarkable root system which consists of a thickened rootstock, secondary feeder roots, and rhizomes. Snow Trillium can reseed itself, but it more often produces vegetative clones from the rhizomes. At favorable sites, colonies are often formed. Such was the case in the ones I saw. Although there were a few outliers, most of them grew in large colonies like the more well-known T. grandiflorum. These fleshy root stalks are well adapted to the thin, rocky soils. Apparently spring-summer heat that has not been shielded in the otherwise sparse landscape has something to do with the growth and maturation of the root stalks in between flowering seasons.Very few insects visit the early-blooming flowers for nectar or pollen. Most likely, the flowers are pollinated by Andrenid bees, queen bumblebees, and other bees that become active early in the spring. The fruits are probably eaten by small mammals and birds, although there is a lack of information regarding the particular species that do this. Recently it has been learned that the seed coating is very sweet and attracts ants which may help either in dissemination or subsequent germination.
Be that as it may, it was a wonderful species to claim on my life list and learning something about its physiology, added to my appreciation of this hardy, but delicate survivor.
