The opening twist (ptyxis) of the spathes of Lagenandra and Cryptocoryne (Araceae)

 

Niels Jacobsen, Jan Bastmeijer, & Marian Ørgaard

 

ABSTRACT

Observations on the opening twist (ptyxis) of the spathes of Lagenandra and Cryptocoryne conclude that the direction of the twist (clockwise vs counter-clockwise) is consistent within an unbranched rhizome but may change when a lateral shoot is produced. The supervolute ptyxis of the vegetative leaves in Cryptocoryne corresponds to that of the spathe within an unbranched rhizome. In Lagenandra the leaf ptyxis is involute so there is no correspondence with the spathe ptyxis. It is hypothesized that in all Araceae with supervolute ptyxis the leaf and spathe ptyxis correspond.

 

KEYWORDS

Cryptocoryne, Lagenandra, limb twist, ptyxis, spathe opening