Gerry Loose, Knopper Gall specimens (caused by a wasp which is parasitic to the acorn of the pedunculate oak); poem-text drawn from gall descriptions in Theophrastus of Eresus’ Historia Plantarum (3rd-2nd century BC).
A bull’s head
when split open
contains a thing
nor does it grow
from an eye
but from the side
of the head
Loose: ‘Knopper galls are caused by a wasp, Andricus quercuscalicis, which needs both the pedunculate oak (Quercus robur) and the Turkey oak (Quercus cerris) to complete its lifecycle.
The wasp is parasitic to the acorn of the pedunculate oak; a chemical causes the disfiguration of the acorn which lends the gall its name. (Knopper is German for knob among other things).
The Turkey oak was introduced into Britain in 1739; the wasp appeared in the 1960s and has gradually made its way north, only through meeting both oaks in proximity, usually in large Estates, where the Turkey oak was planted as a decorative specimen to add value and vista to gentlemen’s wooded landscapes.
It arrived in Scotland in 1995 in Galloway. Now it has recently arrived here: across the river (2004) at Erskine – directly opposite my boat in what used to be Erskine Old Soldiers’ Home and before that a large country house and wooded estate (now golf course, but the trees remain). A speed of roughly ten miles a year. And excitingly, it is reputed to have crossed the river (by the bridge at Erskine?) to the very small glen just along from here – Glen Lusset.
The accompanying labels have on them poem-texts drawn from Theophrastus of Eresus’ Historia Plantarum, where inter alia, he describes several kinds of gall, among them the Knopper gall. (G Senn translation, 1942, Transactions of the Royal Society of Edinburgh.) Theophrastus’ first name was Andricus; the wasp is named for him (Burgsdorf 1783).’