Shortleaf pine is a large tree with a long, clear trunk and broad, open crown.
Leaves are needles, from persistent sheaths at the base of the needles; needles in bundles of 2 (sometimes 3), 3–5 inches long, slender, flexible, not twisted, sharp-pointed, dark bluish-green.
Bark is thick, reddish-brown to nearly black, broken into large, irregular, scaly plates.
Twigs are stiff, stout, rough, brittle, green at first turning gray to reddish-brown with age, usually covered with a whitish coating.
"Flowers" (sheds pollen) March–April, with male and female cones found on the same tree; male cones in clusters at the tips of twigs, yellowish-brown to purple, ¾ inch long.
Fruits September–October, maturing the second year, persistent on the branches, a woody cone in clusters of 1–3, hanging, brown, 1½– 2½ inches long, narrowly egg-shaped; scales separating at maturity, tips with sharp, curved spines.
Similar species: Shortleaf pine is Missouri's only native pine species. The other five pines included in our flora are non-natives that are commonly planted in timber plantations, for wildlife habitat, for erosion control, or as ornamentals: Austrian pine (P. nigra), jack pine (P. banksiana), eastern white pine (P. strobus), loblolly pine (P. taeda), and scrub pine (P. virginiana). These species frequently produce cones and reproduce themselves within their populations, thus they can become naturalized locally and are counted as part of our state's flora. Other pines are grown only as ornamentals or on Christmas tree farms and do not reproduce on their own, so they are not considered part of our flora; these include ponderosa pine (P. ponderosa), red pine (P. resinosa), and Scotch pine (P. sylvestris). The bottom line is, unless you are at an old home site or at a place where the non-native pines have been cultivated and might persist on a local scale, the only type of pine you will encounter in the wild in Missouri is almost always the shortleaf pine.