284 Centaurea cyanus
John Gerard^46 and, though mentioned in at least one later herbal, seems more
likely to have been a folk use adopted by official medicine thanvice versa.Lend-
ing support to that is a twentieth-century Essex record of boiling the flowers
with chamomile heads and applying the mixture as a compress to tired eyes.^47
Centaurea nigra Linnaeus
common knapweed, hardheads; blackheads, blackbuttons
(Ireland)
western Europe; introduced into North America, Australasia
As a medicinal herb almost exclusively Irish, the common Centaurea nigra
has been used in that country principally for jaundice and liver trouble
(Ulster,^48 Cavan,^49 Offaly,^50 Laois,^51 Wicklow^52 ), the decoction of its roots in
milk rivalling dandelion as a treatment for that. That it has also been valued
as a cleansing tonic is suggested by its reputation for removing boils in Lim-
erick^53 and—significantly, if drunk in a mixture with bur-
dock—for curing scurvy in Wicklow.^54 On the Clare-Gal-
way border the same preparation has been drunk
for ‘pains in the bones’ (presumably
rheumatism or osteoarthritis),^55 while in
Donegal a much-favoured remedy local-
ly for ‘the decline’ (presumably tubercu-
losis) was seven stalks of this, seven of
‘fairy lint’ (purging flax,Linum catharti-
cum) and seven of maidenhair,
pounded together and mixed with
seven noggins of water drawn
from a place where three streams
meet^56 ; it may well also be the ‘but-
tonweed’ of which an infusion has
been drunk in Kerry for asthma.^57 It is
possible that more Irish records are hid-
den within the numerous ones for plan-
tain, for both that and knapweed have been
known as ‘blackheads’ in Co. Dublin,^58 Done-
gal^59 and no doubt other counties, too.
The only British use recorded that
is certainly the same as any of the Irish
ones is a reputation for boils in Mont-
gomeryshire^60 ; this plant may, how-
Centaurea nigra, common
knapweed (Green 1902, fig. 354)