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 monoecious; staminate  and pistillate flowers are on the same tree in separate catkins  (aments). Flowers appear at the same time as the leaves.  Flowering usually begins in March in the South and extends  through May further north. Staminate flowers are borne in pendant  catkins 5 to 10 cm (2 to 4 in) long. The calyx is yellow,  pubescent, and five-lobed; the lobes are acute and laciniately  segmented, with four to six stamens and pubescent anthers.  Pistillate catkins are short-stalked or sessile and  inconspicuous; the scales of the involucre are broadly ovate and  hairy with red, short, enlarged stigmas (18).

    The acorns mature in one growing season and drop soon after  ripening, from September through November. Late freezes after the  start of flowering and leafing may cause seed crop failures. The  acorns are sessile or short-stalked, borne solitary, in pairs, or  clustered; acorns are oval or ovoid-oblong, broad at the base, 13  to 19 mm (0.5 to 0.75 in) long, striate, set in a cup one-third  to one-half its length. The cup is bowl-shaped, pale, and often  pubescent within. Externally it is hoary-tomentose. The scales of  the cup are reddish brown, rounded or acute at the apex, and  closely appressed (18).

More info for the term: tree

Post oak is a long-lived, native, deciduous tree with a crown of
horizontal branches. The varieties are distinguished by leaf shape,
acorn size, growth form, and site preferences. The typical variety
usually grows 50 to 60 feet (15.2-18.3 m) in height and 12 to 24 inches
(30-61 cm) in d.b.h. It rarely exceeds 100 feet (30.5 m) in height and
48 inches (122 cm) in d.b.h. [47]. In the drier areas of its range
(Texas), post oak is typically only 30 to 40 feet (9-12 m) tall and 15
to 18 inches (38-46 cm) in d.b.h. Post oak is slow growing and lives
300 to 400 years [24,47]. Seedlings have especially thick taproots.
Most roots develop above underlying clay horizons [47].

Delta post oak is generally larger than the typical variety, growing to
about 100 feet (30 m) in height [13,46].

In the Southeast, mature post oaks are  from 15.2 to 18.3 m (50 to 60 ft) tall and from 30 to 61 cm (12  to 24 in) in d.b.h. Maximum height rarely exceeds 30 m (100 ft),  and diameters exceeding 122 cm (48 in) are uncommon. In the  extreme western part of its range, mature trees are seldom larger  than 9 to 12 in (30 to 40 ft) tall and 38 to 46 cm (15 to 18 in)  in d.b.h. Height and diameter growth for post oak are usually   slower than for any of the associated trees except blackjack oak  ' Ten-year diameter growth generally averages less than 5 cm (2  in), and in central Oklahoma it may be only 13 mm (0.5 in).

    Diameter growth of individual post oaks averaging 17 cm (6.7 in)  in d.b.h. was stimulated when most of the stand was removed to  favor forage production in Robertson County, TX (12). Post oak  stands were thinned from an average of 14.9 m²/ha (65 ft²  /acre) basal area to 8.9, 6.0, and 3.0 m²/ha (39, 26, and 13  ft² /acre). In the two ensuing growing seasons, average  annual diameter growth for the heaviest thinning was twice that  of the uncut check plots (3.6 mm. compared to 1.8 mm, excluding  bark, or 0.14 in compared to 0.07 in).

    Average post oak stands in east Texas contain a volume of about  47.2 m³/ha (7.5 cords or 675 ft³/acre). In an Oklahoma  woodland, typical of the dry upland post oak type, post oaks 30  cm (12 in) in d.b.h. and larger made up 64 percent of the  sawtimber volume (Doyle rule) in a stand averaging nearly 28.0 m³/ha  (2,000 fbm/acre). The average post oak contained 0.4 m' (70 fbm).