Summary The reported hosts of Viscum album include more taxa, than any other mistletoe, including Dendrophthoe falcata. From a review of the literature, we identified hosts among 452 species, subspecies, varieties, and hybrids in 96 genera of 44 families. Rosaceae has the most hosts with 128 taxa parasitized. Commonly infested genera include Salix, Populus, Acer, Malus, Crataegus, Prunus, Sorbus, Abies, and Pinus. The host range of V. album increased greatly with introduction of susceptible taxa into its native range and with spread of the mistletoe to new regions with rich floras, such as California.

The experiments described in this paper were planned to test the effects of certain environmental factors on the root growth of loblolly pine seedlings. TURNER (26) and REED (22) studied the seasonal periodicity of root growth of this species under field conditions, but no measurements were made under controlled conditions. Reed noted a marked reduction in root growth during the time when soil temperatures were lowest and also at times when the soil was driest. Turner's data also indicate this same general trend. It was, therefore, decided to measure root growth of loblolly pine under controlled conditions to find whether or not a definite and perhaps quantitative relationship to soil temperature and other factors could be shown.Materials and methods Two series of experiments were performed, the first during the spring and summer of 1941, the second during the winter of 1946. The seedlings used in 1941 were grown from seed collected in North Carolina in 1940, and the seedlings used in 1946 were grown from seed collected in Louisiana in 1945.The seedlings were grown in glass tubes about two inches in diameter and 18 inches long. These tubes were closed at the lower end with rubber stoppers and a layer of cinders placed over the stoppers. The tubes were