Answer: Well.... there can be some confusion because red oaks hybridize with other red oaks and the distinguishing characteristics sometimes take a magnifying glass to see! Here's the story: Shumard oak is a deciduous tree that usually gets about 75' tall with a broad, open crown that spreads about 40'. On good sites, Shumard oak is one of the largest of the southern oaks, reaching more than 100' in height with a tall, straight trunk 4 or 5' in diameter. It sometimes gets even larger: the record Shumard, in South Carolina, is 155' tall with a trunk diameter over 6' and a crown spread of 116'! The leaves are variable, 6-8" long, with 7, 9 or 11 bristle-tipped lobes with sinuses that extend half way to the midvein. In fall the leaves turn red or golden brown. The flowers are typical of oaks in general: female flowers are tiny and held in small inconspicuous spikes, and male flowers are clustered in hanging catkins about 6" long. Flowers appear with the opening of the leaves in early spring. The acorns are about an inch long with a deep, saucer-shaped cup that encloses about a third of the nut.
Shumard oak looks a lot like scarlet oak (Q. coccinea), which has smaller leaves; and northern red oak (Q. rubra), which has leaves less deeply lobed and an acorn whose cup encloses only a quarter of the nut.
Shumard oak hybridizes with other oak species including southern red oak (Q. falcata), willow oak (Q. phellos), water oak (Q. nigra), and blackjack oak (Q. marilandica), and the results of such miscegenations may look like either parent or something in between or even something unlike either parent.
Southern red oak (Q. falcata) has hairy winter buds and smaller acorns that are only 0.5 in (1.3 cm) long with cups extending about a third of the way up the nut.
Hope this helps clear up the confusion!
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