. Manual of tree diseases . Trees. SPRUCE DISEASES 323 The mistletoe plant is very small. It is usually less than a half inch tall but may grow as large as one inch. The pollen and seed are produced on separate plants which usually grow on different trees. The plants con- sist of a short stem with appressed scale-like leaves. They are either yellowish or dark colored. Cavse. The witches'-broom of spruce is caused by the dwarf mistletoe, Ra- zoumofskya pusilla. The floral organs of the plant are matiu-e in early spring and the seeds are ready to be disseminated in September. Before the seeds ar
. Manual of tree diseases . Trees. SPRUCE DISEASES 323 The mistletoe plant is very small. It is usually less than a half inch tall but may grow as large as one inch. The pollen and seed are produced on separate plants which usually grow on different trees. The plants con- sist of a short stem with appressed scale-like leaves. They are either yellowish or dark colored. Cavse. The witches'-broom of spruce is caused by the dwarf mistletoe, Ra- zoumofskya pusilla. The floral organs of the plant are matiu-e in early spring and the seeds are ready to be disseminated in September. Before the seeds are discharged, the plants bend toward the tip of the branch. In this position the seeds are forcibly projected and being sticky they adhere to the younger twigs on which they may lodge. Rootlets are sent into the bark and wood of Fig. 63. —Mistletoe witches'-brooms on the twig and a parasitic black spruce. Tree almost dead. relation established. The increased growth of the branches and the formation of the witches'-brooms are due to the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Rankin, W. Howard (William Howard), b. 1888. New York : The Macmillan Company
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1918
