Abstract: Warty layers on the inner surface of tracheids in 11 families, 41 genera, 99 species of the Chinese gymnosperms were observed systematically. Present or absent, distributing densities, sizes and shapes of the warty layers are some valuable for the classification of families, genera and even species of the gymnospermous woods.1. Warty layers on the inner surface of tracheids have been found in concentrating in Taxodiaceae (except Taiwania, Taxodium, Metasequoia), Cupressaceae (except Thujopsis, Thuja), and Keteleeria, Abies, Tsuga, Cedrus, and part of the species in Pinus of Pinaceae, but have not been observed in Podocarpaceae, Cephalotaxaceae, Taxaceae (except Pseudotaxus, Torreya), and Pseudotsuga, Picea and Larix of Pinaceae.2. Warts in Pinus bungeana are more bigger than the other species of subgen. Strobus. There are distinct warts on the inner wall and rare warts on the border of pits in their tracheids. Based on its anatomical characteristics of wood, chemical composition of heartwood and strure of needles, suggestion may be proposed that P. bungeana would be promoted from Sect. Parrya to Subgen. Parrya.3. Within an annual ring, the warts diameter of latewood tracheids were generally larger than those in earlywood tracheids and their distributing density was in decreasing. And less difference was found in size and distributing density of warts between both the radial and tangential walls of a tracheid.4. When wood sections (12 species) were treated with 0.5% sodium hypochlorite, the warts of 7 species on the inside of tracheid lumens decreased 57%, its distributing density decreased 52%. The warts have not been seen in the other 5 species.5. The warty layers (in 6 species) also can be dissolved by white rot and some soft rot species.

Key words: Warty layer, Warts, Gymnospermous woods, Tracheids