The ranges of mucilage layer in mycorrhizosphere of loblolly pine and slash pine were foundwider than their common root rhizospheres. The former varies within a range of 50 μm× 55μm and90 μm ×70 μm, and the latter within a range of 20 μm ×(30～ 40) μm and 50 μm. The ranges of mucilsge layer expand owing to the activity of mycorrhizas, producing not only mucilages but also fungalhyphae themselves.