A Tree Tumor of Unknown Origin

Publisher Website
Google Scholar
Abstract
Tumors of unknown origin are described in the white spruce, Picea glauca. The tumors are smooth, round growths that may develop into globose structures a meter or more in diameter. Sections show that, irrespective of size, the tumors always extend all the way to the pith and therefore must arise in the bud. Tumor sectors have somewhat thinner cell walls and slightly larger lumens but the cell size is not sufficiently different from that of adjacent normal wood to account for the massive character of the external growths. Tissue cultures isolated from tumors are much more variable in rate of growth, growth pattern, color and nutrient requirements than are corresponding cultures from normal wood. These tumors are not typical crown galls, typical insect galls, or typical irritation teratomas.