Multiple causes of seedling rarity in scrub plum, Prunus geniculata (Rosaceae), an endangered shrub of the Florida scrub

Carl W. Weekley, David N. Zaya, Eric S. Menges, Amy E. Faivre

Research output: Contribution to journalArticlepeer-review


Conservation of an imperiled plant often requires an understanding of its reproductive ecology. Scrub plum (Prunus geniculata) is an endangered Florida shrub endemic to pyrogenic xeric uplands. Although plants are long-lived and may flower profusely, particularly after burning, fruit yield is sparse and seedlings are rare. We investigated potential causes of seedling rarity in scrub plum by studying its floral sex and breeding systems, fruit development, and germination ecology. We also developed a flow chart based on two time-since-fire scenarios to illustrate the cumulative impact of these factors on seedling recruitment. Breeding system experiments suggested partial gametophytic self-incompatibility in this functionally andromonoecious species, with inbreeding depression in self-compatible individuals. Predispersal seed predation, the major constraint on seedling recruitment, was lower in the first postburn season. In two field experiments, seed germination was < 11% irrespective of treatment. These results indicate that seedling recruitment in scrub plum may be limited by multiple factors, including sexual reproductive failure, high predispersal seed predation, and low seed germination. The chance of a bisexual flower producing a seedling ranges from 5 in 1000 to 5 in 100 000, depending on the time since fire. Restoration of scrub plum's historical fire regime may mitigate some of these factors.

Original languageEnglish (US)
Pages (from-to)144-155
Number of pages12
JournalAmerican journal of botany
Issue number1
StatePublished - Jan 2010
Externally publishedYes


  • Andromonoecy
  • Endangered species
  • Fruit maturation
  • Inbreeding depression
  • Lake wales ridge
  • Predispersal seed predation
  • Prunus geniculata
  • Rosaceae
  • Seed germination

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Plant Science


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