This photo is for Kate, Shawn, & Maya— to add some plant-talk to my blog! Nearby my house there are a few patches of Yucca filamentosa, an evergreen belonging to the Asparagaceae family (Agavoideae). In Missouri, the native range of two other yucca species extends into the northwestern edge and the Southern Ozarks, but Y. filamentosa has become established here and up through New England due to cultivation. This species gets its name from curly wispy filaments that protrude from the basal rosette of pointed rigid leaves. A single stalk emerges from a rosette’s center to stretch ~7–8 feet tall with a branched inflorescence (panicles) of large white flowers. After the petals fall, tripartite seed pods will mature, eventually drying and breaking open as dry husks containing stacks of black seeds.
Yucca filamentosa participates in an obligate pollination mutualism with the prodoxid moth Tegeticula yuccasella. When flowers receive out-crossed pollen, both yucca seeds as well as developing moth larvae incur higher fitness, whereas self-pollination results in a greater incidence of flower abscission (shedding), which contributes to larval mortality. However, yucca moths actively deposit self-pollen, seemingly to the detriment of both parties. One study argues that selection against self-pollination behavior in moths may be weak due to the benefits of maximizing oviposition output within a near radius. If plants favor using outcross pollen for fertilization when having a ‘mixed bag’ of pollen, it would also mitigate the negative effects of self-pollination.