Trillium recurvatum

Trillium recurvatum typically grows on floodplains with rich clayey soils, in rich woods or on bluffs typcially, but not always, on calcareous substrates. The plants can be temporarily inundated on the floodplain and often are when they flower (Case and Case 1997).

Trillium seeds have an elaiosome, an oily, lipid-rich attachment that is highly attractive to ants. The ants carry the seeds to their nest, eat the attachment, and leave the seeds in tunnels in their nests (FNA 2002a, Leege et al. 2010). The seeds later germinate en masse (Case and Case 1997). Yellow jackets (Vespula spp.) and other wasps are similarly attracted to the elaiosome. Yellow jackets are documented seed dispersers for three species (T. catesbaei, T. cuneatum, T. undulatum) (Zettler et al. 2001). Ants carry the seeds an average of about 1m whereas yellow jackets disperse seeds an average of 1.4m (Chafin 2010, Zettler et al. 2001). Long distance dispersers include mammals, such as white-tailed deer (Odocoileus virginianus) and woodchucks (Marmota monax) (Chafin 2010, Vellend et al. 2006). Similarly, it is suspected that elk (Cervus canadensis) and mule deer (Odocoileus hemionus) of the western U.S.A. are capable of dispersing seeds over long distances (Bartuszevige and Endress 2008).

Trillium recurvatum is a long-lived species that is self-incompatible, but also reproduces by clonally. In Mendal et al. (2019) that the population of T. recurvatum harbors a moderate level of genetic diversity, and that 81 unique genets were present out of the 176 they sampled. Further, their study showed that sexual and asexual reproduction occurred equally. Mendal et al. (2019) found that more sexual reproduction occurred in the focal population than previously thought. Additionally, flowering individuals, which made up the minority of the ages classes sampled, regress to non-flowering individuals in years subsequent to deer predation, as exhibited by other clonal species (Mendal et al. 2019).

Trillium seeds exhibit a somewhat unique kind of dormancy called deep simple double morphophysiological dormancy, meaning they require two winters and one summer to complete dormancy break. After dispersal, roots (radicles) emerge in the first spring and leaves (epicotyls) begin growing in the second spring. The result is that Trillium seeds are generally about 1.5-2 years before they are non-dormant. If root emergence does not occur during the first spring, the next opportunity for root emergence would be the third spring and epicotyl emergence would occur during the fourth spring after dispersal (Walck et al. 2005). Age to maturity, or flowering, is variable and has been recorded from 4 to 20 years depending on growing conditions (Case and Case 1997).