Editing Quercus robur (section)

==Description==
Pedunculate oak is a [[deciduous]] tree up to {{Convert|40|m}} tall,<ref name="Stace-2019">{{cite book |last1=Stace |first1=C.A. |title=New Flora of the British Isles |date=2019 |location=Suffolk |publisher=C & M Floristics |edition=4th |isbn=978-1-5272-2630-2}}</ref> with a single stout trunk that can be as much as {{Convert|11|m|abbr=on}} in girth (circumference at breast height) or even 14 m in [[Pollarding|pollarded]] specimens. Older trees tend to be pollarded, with boles (the main trunk) about 3 m long. They often live longer and become more stout than unpollarded trees.
[[File:Oak bark.jpg|thumb|Oak bark.]]

The crown is spreading and unevenly domed, and trees often have massive lower branches. The bark is greyish-brown and closely grooved, with vertical plates. There are often large burrs on the trunk, which typically produce many small shoots. Oaks do not produce [[Basal shoot|suckers]] but do recover well from pruning or lightning damage. The twigs are hairless and the buds are rounded (ovoid), brownish and pointed.<ref name="Stace-2019"/><ref name="Mitchell-1974">{{cite book |last1=Mitchell |first1=Alan |title=A Field Guide to the Trees of Britain and Northern Europe |date=1974 |publisher=Collins |location=Glasgow |isbn=0-00-219213-6}}</ref><ref name="Rose-2006">{{cite book |last1=Rose |first1=Francis |title=The Wild Flower Key |date=2006 |publisher=Frederick Warne |location=London |isbn=978-0-7232-5175-0}}</ref>

The [[leaves]] are arranged alternately along the twigs and are broadly oblong or ovate, 10–12 cm long by 7–8 cm wide, with a short (typically 2–3 mm) [[Petiole (botany)|petiole]]. They have a cordate (auricled) base and 3–6 rounded lobes, divided no further than halfway to the midrib. The leaves are usually glabrous or have just a few simple hairs on the lower surface. They are dark green above, paler below, and are often covered in small disks of spangle gall by autumn.<ref name="Mitchell-1974" />

[[File:Quercus robur flowers kz01.jpg|thumb|Male flowers]]
Flowering takes place in spring (early May in Northern Europe) and the flowers are wind-pollinated. The male flowers occur in narrow catkins some 2-4 cm long and arranged in small bunches. The female flowers are small, brown with dark red stigmas, about 2&nbsp;mm in diameter and are found at the tips of new shoots on peduncles 2–5&nbsp;cm long.<ref name="Mitchell-1974" />

The fruits (acorns) are borne in clusters of 2–3 on a long peduncle (stalk) 4–8&nbsp;cm long. Each acorn is 1.5–4&nbsp;cm long, ovoid with a pointed tip, starting whitish-green and becoming brown, then black. As with all oaks, the acorns are carried in a distinctive shallow cup which can be useful in identifying the species.<ref name="Mitchell-1974" /> It is an "alternate bearing" species, with large crops produced every other year.<ref name="Crawley-2005">{{cite book |last1=Crawley |first1=M.J. |title=The Flora of Berkshire |date=2005 |publisher=Brambleby Books |location=Harpenden |isbn=0-9543347-4-4}}</ref>

=== Chemistry ===
[[Grandinin]]/[[roburin E]], [[castalagin]]/[[vescalagin]], [[gallic acid]], monogalloyl glucose ([[glucogallin]]) and [[valoneic acid dilactone]], monogalloyl glucose, [[digalloyl glucose]], [[trigalloyl glucose]], [[rhamnose]], [[quercitrin]] and [[ellagic acid]] are phenolic compounds found in ''Q. robur''.<ref>Analysis of oak tannins by liquid chromatography-electrospray ionisation mass spectrometry. Pirjo Mämmelä, Heikki Savolainenb, Lasse Lindroosa, Juhani Kangasd and Terttu Vartiainen, Journal of Chromatography A, Volume 891, Issue 1, 1 September 2000, Pages 75–83, {{doi|10.1016/S0021-9673(00)00624-5}}</ref> The heartwood contains [[triterpene saponin]]s.<ref>Identification of triterpene saponins in Quercus robur L. and Q. petraea Liebl. Heartwood by LC-ESI/MS and NMR. Arramon G, Saucier C, Colombani D and Glories Y, Phytochem Anal., November-December 2002, volume 13, issue 6, pages 305–310, {{PMID|12494747}}</ref>

=== Similar species ===
''Q.&nbsp;robur'' is most likely to be confused with [[Quercus petraea|sessile oak]], which shares much of its range. Distinguishing features of ''Q.&nbsp;robur'' include the auricles at the leaf base, the very short petiole, its clusters of acorns being borne on a long peduncle, and the lack of stellate hairs on the underside of the leaf. The two often [[Hybrid (biology)|hybridise]] in the wild, forming ''[[Quercus × rosacea]]''.<ref name="Stace-2019" />

[[Quercus cerris|Turkey oak]] is also sometimes confused with it, but that species has "whiskers" on the winter buds and deeper lobes on the leaves (often more than halfway to the midrib). The acorn cups are also very different.<ref name="Crawley-2005" />