Bur Oak Quercus macrocarpa MichauxS1S2 (Highly state rare)    
Kingdom Plantae   >   Division Tracheophyta   >   Class Magnoliopsida   >   Order Fagales   >   Family Fagaceae   >   Genus Quercus   

Status:

Bur Oak is more common in the midwestern and plains states than in the East. It grows farther north than any other oak (Stein et al., 2003). In Maryland, it is rare.

Description:

The features most salient for identification purposes are the leaves, which have "5-7 pairs of blunt or rounded lobes separated by deep, rounded sinuses, the middle pair of sinuses the deepest, the upper ones more shallow, the broader terminal portion of the blade with a rounded or 3-lobed apex...."; and the acorn cup, which is "composed of large, tomentose [hairy], imbricated [shingle-like] scales covering one-third to nearly all of the nut, the upper scales tapering to long, awn-like tips, forming a fringe from whence the word Bur Oak is derived" (Brown and Brown, 1972). The leaves have a fine, dense hairiness below.

Where to find:

Bur Oak grows in bottom lands, in rich, moist woods, and on floodplains (Brown and Brown, 1982), and also occurs on very dry sites (Stein et al., 2003).

Relationships:

Host plant for various butterfly species including Banded Hairstreak.

Host plant for various moth species including Banded Tussock Moth (Database of World's Lepidopteran Host Plants).

There are 16 records in the project database.

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Bur Oak leaf hosting a Hedgehog Gall Wasp (Acraspis villosa) in Frederick Co., Maryland (7/8/2014). Photo by Richard Orr. (MBP list)

The acorn of a Bur Oak, the upper scales of the cup bearing the fringe typical of the species, in Marion Co., Ohio (9/4/2007). Photo by Robert Klips. (MBP list)

Bur Oak leaves, showing typical deep middle sinuses, and trunk in Anne Arundel Co., Maryland (9/11/2012). Photo by Bill Harms. (MBP list)

Bur Oak (leaves) in Baltimore City, Maryland (5/25/2019). Photo by Bill Hubick. (MBP list)

Bur Oak (underside of leaf) in Baltimore City, Maryland (5/25/2019). Photo by Bill Hubick. (MBP list)

Bur Oak trunk in Baltimore City, Maryland (5/25/2019). Photo by Bill Hubick. (MBP list)

The state champion Bur Oak at the Maryland Zoo in Baltimore City Co., Maryland (5/25/2019). Photo by Bill Hubick. (MBP list)


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