Reproductive structure

A substantial literature dating back more than a century describes the bro-meliad reproductive apparatus. Taxonomists working with dried specimens authored most of the early treatments. Interest continues, but specimen quality has improved allowing analyses to be more comprehensive. For example, Brown and Terry (1992) used liquid-preserved owers and scanning electron microscopy to determine that the delicate petal scale that gures so prominently in the most recent monograph of the family (Smith and Downs 1974, 1977, 1979; Fig. 3.1) circumscribes some genera more convincingly than others. Wet material has also permitted determinations of when certain features appear during ontogeny, and accordingly, their utility for distinguishing taxa of low vs. higher rank.

Plant form underlying reproductive phenomena like pollination and seed dispersal and the genetic structure of populations are our primary concern for this review. Unfortunately, few of the hundreds of publications devoted to the reproductive apparatus of Bromeliaceae provide much insight on any of these subjects. Moreover, inquiry on owers, fruits and seeds continues to be motivated primarily by interests in systematics. The exceptional report that does depart from tradition usually addresses the same question, namely who pollinates which bromeliad?

Today, molecular biology is augmenting the morphological data traditionally used to infer bromeliad history. However, cladograms based on nucleotide sequences must be more fully resolved than those illustrated in Chapter 9 to produce the phylogeny necessary to determine where, when and how often decisive features of the reproductive apparatus evolved. Additional information on gross morphology is also needed to address questions such as whether the different conditions of the ight apparatus of the seeds of Tillandsioideae re ect separate origins (Palaci 1997). Speci cally, do Tillandsia/ Vriesea vs. Catopsis or Glomeropitcairnia share homologous or convergent coma morphology?

Was this article helpful?

0 0

Post a comment