Persistence and development of Dasya baillouviana (Gmelin) Montagne (Rhodophyceae, Dasyaceae) in North Carolina

Abstract Macroscopic plants of Dasya baillouviana (Gmelin) Montagne [D. pedicellata (C. Agardh) C. Agardh] were present at an inshore North Carolina study site from February to May (winter through spring). Field experiments with artificial substrata determined that this eurythermal, wide ranging species persists the remainder of the year at this location by means of perennating, prostrate discs. One generation of macroscopic plants appears each year, and macroscopic plant growth from settled spores does not occur until the next growing season. Laboratory experiments showed that day-length was the environmental factor controlling the seasonal appearance of macroscopic plants by stimulating or inhibiting sympodial, polystichous growth from uniseriate germlings. Development of the macroscopic plants in culture is described.