ULTRASTRUCTURE OF CELL-DIVISION IN AGARDHIELLA-SUBULATA (GIGARTINALES, RHODOPHYTA)

The fine structure of cell division in Agardhiella subulata is consist ent with the basic pattern observed for most multicellular red algae. Unusual features include complete microtubule-filled tunnels through t he nucleus (prophase), a nucleus-associated organelle penetrated by th e outer membrane of the nuclear envelope (prophase) and a metaphase-an aphase polar region that appears in thin section as two large gaps sep arated by a central intact fragment of nuclear envelope. The only othe r red alga in which the latter two features have been detected is Lome ntaria baileyana (Rhodymeniales). This study is the first complete ult rastructural description of cell division in a member of the Gigartina les. In addition, it provides information on features that may be usef ul as taxonomic indicators for members of the Gigartinales and the Rho dymeniales.