The warm-temperate speciesChondria baileyana,Lomentaria baileyana,Griffithsia globifera, andDasya baillouvianaare restricted, north of Cape Cod on the eastern American coast, to embayments and estuaries. The northern limit of distribution is the southern Gulf of St. Lawrence. In culture, isolates of these species from Nova Scotia survived 28 to 34 °C. In the field all reproduced during the period of maximum temperature, and inG.globiferaandC.baileyanathe progeny also reproduced. Some of the progeny ofD.baillouvianadeveloped as cold- and heat-resistant pads that survived the winter, whereas the other three species died back to perennating holdfast structures.Lomentaria baileyanawas the least successful of the group, being unable to form resistant holdfast pads in midsummer temperatures and having the most limited reproductive period and smallest population size.