274 
THE PLANT WORLD. 
having been subjected to pressure by them, and the walls of such 
cells are suberized. . . . the solvents secreted by the haustoria 
of the parasite do not dissolve suberized walls, and apparently 
cannot do so.”* Dr. Cannon emphasizes the fact that the haus¬ 
toria never penetrate farther than the cortex, but Peirce pictures 
the haustoria of Arceuthobium occidentale as having passed the 
cambium and penetrated the wood through a medullary ray. 
While the haustoria are spreading in the interior of the host, 
the vegetative portion of the parasite grows upward from the 
bark; the cotyledons are detached from the sticky seed-coat; 
Fig. 56. Seedling of Dendropthora gracilis germinating on a juniper 
branch, Jamaica, B. W. I. The end of the hypocotyl has been trans¬ 
formed into an adhesive disc. The seedling is surrounded by a sticky 
substance. 
branches grow out from buds, and soon we have a flowering plant, 
as well able to form chlorophyll, to assimilate its food, and to 
reproduce itself as any other phanerogam, but unable, because de¬ 
prived of true roots, to obtain water from the soil. 
An interesting feature of the mistletoe is its influence on the 
host plant. Often the tissues of the host in the region of the 
parasite show abnormal structures, the branches are stimulated 
to increased growth, while the development of the nearest buds 
* Cannon, W. A. Bull. Torrey Club, 31: 435-443. August, 1904. 
