Anatomical modifications in protective layers and stomatal characteristics of needles which would have moisture conserving effects were found in 2-yr-old seedlings of 1oblolly pines of the Bastrop County, Texas, provenance. Most of these modifications were absent from needles of 16-yr-old trees of the same provenance. Forest Sci. 20:88-90.
Bilan, M. Victor and Knauf, T.A., "Needle Variation in Loblolly Pine from Mesic and Xeric Seed Sources" (1974). Faculty Publications. 359.