Figure 1.

The Lemnaceae family is a sister lineage to other extant monocot families that has readapted to an aquatic lifestyle. (A) Phylogenetic relationship between the greater duckweed (Spirodela, Lemnaceae, Alismatales) and other branches of the angiosperms. The genus names are shown immediately to the right of the tree diagram, followed by the family names. WGD events are shown in black circles at the approximate time during their evolutionary history. “A field in a flask”: a culture of Wo. globosa (B) or Sp. polyrhiza (C) plants in a flask of growth medium. (D) Turions are a dormant form of many Lemnaceae species that enable these simple plants to overwinter at the bottom of their resident water bodies. Pictured is a clone of Sp. polyrhiza under low phosphate conditions in the growth medium. A typical growing frond cluster is shown in the middle, surrounded by turions. DF, daughter frond; MF, mother frond; T, turion.