The white flowered form of Trillium erectum. This plant was in the wild in Great Smoky Mountains National Park.
Trillium flexipes
The flower on this garden plant is old and is starting to senesce. Note that the flower petals, ovary, and stamens are a creamy white.
Trillium vaseyi
The nodding flower is carried below the leaf bracts. The ovary is red, but the anthers are white. This species is native to the lower slopes of the mountains of North and South Carolina. It also reaches into eastern Tennessee and northern Georgia.
Trillium grandiflorum
The flower is a pure, almost translucent white, and the stamens are yellow. Often, the flowers of this species turn a pinkish color as the flower ages.
Trillium nivale
This dwarf species blooms a month or more before grandiflorum and flexipes do, here in central Indiana. The plant reaches a height of only about 3 inches (ca. 75 mm). As the fruit develops, the pedicel curves downward until the fruit is touching the ground. The range is scattered from southwestern Ohio across Indiana and Illinois through much of Iowa. Isolated occurrences reported in Michigan, Wisconsin, West Virginia and Pennsylvania. I am growing mainly the Illinois form in my garden. It appears to be slowly increasing here.
Trillium rugelii
Trillium simile
Trillium simile, showing the full form and red ovary typical of this species. It is found in eastern North Carolina and around GAtlingburg, Tennessee. There appears to be a cline of intergradation from simile in Gatlinburg to T. erectum album at Newfound Gap in the Great Smoky Mountains National Park.
Trillium sulcatum
The flower has wide petals, form similar to T. simile, but the petals are red. Ovary is red, stigma and anthers are white. Range is from southwestern Virginia and northwestern North Caroline southwestward in a somewhat narrow band through Tennessee, just barely reaching into the corners of Georgia and Alabama.
Sessile Species
Trillium cuneatum
Case says this is the largest of the eastern sessile Trillium species. The leavces are mottled and the pertals are eerect and variable in shape form cuneate to elliptical to oblanceolate; their color varies from maroon to bronze to yellow. It ranges from western North Carolina to south central Kentucky and southward through central Tennessee into northern Georgia and adjacent South CArolina, the northern half of Alabama, and parts of east-central Mississippi. This is a garden plant.
Trilleum luteum
f. luteum
This is the yellow form, but with more green than some show.
red form
This is the red form of luteum. This plant is in Gatlinburg, but the red forms are quite rare while the yellow forms are abundant along roadsides.
Trillium recurvatum
This species has two noteworthy traits: The sepals point downward, pushing between the leaf bracts; and the leaf bracts themselves are carried on short "pedicels" of their own.
Wild collected plants from central Indiana.
Close-up showing the sepals pointing down.
Trillium sessile
Pollinators of Trillium
Trillium grandiflorum, with its white flowers and nectar, is pollinated by Hymenoptera, including honey bees, bumblebees, and perhaps wasps. Trillium erectum, at least the dark red form, has no nectar and is pollinated by flies (Diptera) and beetles (Coleoptera). It remains to be seen how widely these observations can be generalized. We also need to capture the species found visiting flowers of red erectum and identify them more specifically.
The white Trillium simile is a puzzle. The only insects seen visiting those flowers have been small flies (Drosophila or Syrphids or?) and weevils (Coleoptera). This species and its relation to erectum album need much more study.
Although T. cuneatum and T. luteum seem to be sibling species, or even two forms of a single species, it has been suggested that small flies visit cuneatum but flies have not been seen on luteum. This pair of species also needs more investigation.
