24 BOTANICAL GAZETTE [JULY 
latter grew in absolute contact with brooms on Douglas fir bearing 
pistillate plants. As previously stated, however, this is not con- 
clusive evidence of the host range of a species. Accident of infec- 
tion is too great; besides, trees growing in such juxtaposition are 
very often suppressed, thus reducing the amount of vulnerable 
tissue. These results were obtained only by the most careful 
placing of the seeds at the most susceptible points. In the course 
of years such conditions occur in nature. Afterward, as a matter 
of course, further infection from the parent tree to others of its 
kind may be easier. The type of broom produced by R. Douglasiz 
varies with age and host. On hosts with strongly excurrent growth, 
such as Abies lasiocarpa and A. grandis, the brooms are usually 
erect, but drooping or swaying forms occur. The erect type of 
broom is common on Pseudotsuga taxifolia during the first years of 
infection, but later may assume the weeping willow form. 
Seeds from plants on Abies lasiocarpa were sown on a single 
individual each of Tsuga heterophylla, Larix occidentalis, Pinus 
monticola, Thuja plicata, and Populus trichocarpa, but without 
results. Seeds from plants on Pseudotsuga taxifolia were without 
result on these hosts and also on Larix europea, Picea sitchensis, 
P. canadensis, P. excelsea, P. Parryana, Sequoia gigantea, Pinus 
ponderosa, P. contorta, P. Jeffreyi, P. sylvestris, Betula occidentalis, 
Alnus tenutfolia, and Pyrus. ‘The several species of Picea were not 
in a vigorous condition, having been transplanted only a short time 
before the seed were sown. 
SumMARY.—The foregoing cultures indicate that Razoumofskya 
Douglasii abietina is identical with R. Douglasii. The hosts. of 
R. Douglasit as known to the writer are Pseudotsuga taxifolia, Picea 
Engelmanni, Abies concolor, A. grandis, A. lasiocarpa, A. nobilis, 
and A. amabilis. The species is of economic importance only on 
Pseudotsuga taxifolia. 
Cultures with lodgepole pine mistletoe 
This species (R. americana |Nutt.| Kuntze) (figs. 16, 17) is one 
of the most characteristic of the genus. In order to determine its 
host range, the results of some recent cultures are presented in 
table V. It is shown that Pinus contorta is the true host of R. 
