Quercus stellata Wangenh.  

Trees , deciduous, to 20(-30) m. Bark light gray, scaly. Twigs yellowish or grayish, (2-)3-5 mm diam., densely stellate-pubescent. Buds reddish brown, ovoid, to 4 mm, apex obtuse or acute, sparsely pubescent. Leaves: petiole 3-15(-30) mm. Leaf blade obovate to narrowly obovate, elliptic or obtriangular, 40-150(-200) × 20-100(-120) mm, rather stiff and hard, base rounded-attenuate to cordate, sometimes cuneate, margins shallowly to deeply lobed, lobes rounded or spatulate, usually distal 2 lobes divergent at right angles to midrib in cruciform pattern, secondary veins 3-5 on each side, apex broadly rounded; surfaces abaxially yellowish green, with crowded yellowish glandular hairs and scattered minute, 6-8-rayed, appressed or semi-appressed stellate hairs, not velvety to touch, adaxially dark or yellowish green, dull or glossy, sparsely stellate, often somewhat sandpapery with harsh hairs. Acorns 1-3, subsessile or on peduncle to 6(-40) mm; cup deeply saucer-shaped, proximally rounded or constricted, 7-12(-18) mm deep × (7-)10-15(-25) mm wide, enclosing 1/4-2/3 nut, scales tightly appressed, finely grayish pubescent; nut light brown, ovoid or globose, 10-20 × 8-12(-20) mm, glabrous or finely puberulent. Cotyledons distinct.

Post oak is susceptible to most insects,  diseases, and pollutants that present a threat to other oaks.  Regeneration efforts are hampered by acorns being destroyed by  weevils. Insect defoliators, leafrollers, tent caterpillars,  Gypsy moth, sawfly, leaf miners, and skeletonizers may cause  growth losses, and when repeated, may cause mortality (14). The  foliage also is susceptible to at tacks by aphids, lace bugs,   various scales, gall wasps, and mites. The trunk, twigs, and  roots may be damaged by carpenterworms, borers, beetles, twig  pruners, white grubs, and cicadas (locusts). Some of these cause  defects that render the wood unfit for many commercial purposes  (1).

    Chestnut blight fungus (Cryphonectria parasitica) causes  many defects as well as mortality to post oak throughout its  range (8). The tree also is subject to oak wilt (Ceratocystis  fagacearum), a vascular disease prevalent mostly north of the  35th parallel, but not to the same degree as on red oaks.  Soil-inhabiting fungi may cause heavy seedling mortality by  damping off. Powdery mildews stunt and deform nursery seedlings.

    Many fungi produce spots, blotches, blisters, and blights on the  foliage. They rarely cause real damage but are unsightly.

    Decay fungi cause cankers, rots, and discoloration of the upper  and lower stem, as well as of the roots. The Texas root rot (Phymatotrichum  ormnivorum) attacks mainly oaks planted on old farm fields or  in subdivisions (14).

    Several species of mistletoe are often found on branches and  trunks of post oak. Infected branches may be stunted and  eventually die. Trees usually are not killed.

    Nonpoint source pollutants near large cities cause twigs of many  oaks to die back, or kill the trees. The specific diagnosis is  usually difficult. Sulfur dioxide, fluoride, ammonia, and some  herbicides have been identified as probable agents.

Ala., Ark., Conn., Del., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Md., Mass., Miss., Mo., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Va., W.Va.

In common with many  other oaks, post oak begins to bear acorns when it is about 25  years old. Good acorn crops are produced at 2- to 3-year  intervals; although at several locations in Missouri over a  6-year period, post oak consistently averaged only 200 seeds per  tree per year while white, blackjack, black, and scarlet oaks of  the same size on the same site bore from 500 to 2,400 acorns per  tree. Isolated trees in open fields in east Texas consistently  produced well. Elsewhere in Texas, trees less than 15 cm (6 in)  in d.b.h. had no acorns (12).

    The number of post oak acorns per kilogram averages 838 (380/lb)  but may range from 441 to 1,340 (200 to 608/lb) (17).

    In a sampling of post oak acorn yields from 736 trees for 18 years  (1950-67) in western Louisiana and eastern Texas, the average  number of fresh acorns per kilogram was 476 (216/lb) with 39  percent moisture content (5). Mast yield increased linearly with  increasing bole size. Expected acorn yield was 1.6 kg (3.6 lb)  from trees 30.5 cm (12 in) in d.b.h., and 3.6 kg (8.0 lb) from  trees 50.8 cm (20 in) in d.b.h. The percentage of acorn-producing  trees also increased with increasing d.b.h. from 42 percent on  15.2 cm (6 in) trees to 76 percent on 55.9 cm (22 in) trees.  Expected acorn yield rose from 0.9 kg (2 lb) on trees with a 3.0  ni (10 ft) crown diameter to 5.5 kg (12.1 lb) on trees with a 6.1  m (20 ft) crown diameter. Average acorn yield per tree over the  18-year observation period varied from a low 0.03 kg (0.07 lb) in  1962 to a high 4.4 kg (9.7 lb) in 1965.