PYRETHRUM INODORUM. SCENTLESS MAY-WEED,
OR CORN FEYER-FEW.
PYRETHRUM inodorum; foliis bipinnatis, pinnis lineari-filiformibus bi- vel tri-partitis, caule diffuse
ramoso, pappo integerrimo. Willd.
PYRETHRUM inodorum. Smith Engl. Bot. t. 676. Fl. Brit. p . 901. Willd. Sp. PI. ml. 3. p. 2 157.
Decand. Fl. Fr. ed. 3. ml. 4 .p . 184. Fl. Gall. Syn.p. 287. Alton Hort. K m . ed. 2.
ml. 5 .p . 99-
CHRYSANTHEMUM inodorum. Linn. Sp. PL p . 1253. Light/. Scot. p. 488. With. Bot. Arr.
ed. 4. ml. 3. p . 7 18. Hoffm. Germ. ed. 2 . ml. 1 . P . II. p . 158. Pers. Syn. PI.
ml. 2. p. 462. Wahl. Fl. Lapp. p. 2 12. Oed. Fl. Dan. t. 696.
MATRICARIA inodora. Huds. Angl. p. 372.
CHAMiEMELUM inodorum annuum humilius, foliis obscure virentibus. Dill, in Raii Syn.p. 186.
Class a nd Ord e r . SYNGENESIA POLYGAMIA SUPERFLUA.
[Natural Ord e r . COMPOSITE, D iv . III. CORYMBIFERiE, Decand. CORYMBIFERiE, Juss.y
Gen. Cha r. Receptaculum nudum. Pappus marginatus. Calyx hemisphasricus, imbricatus; squamis acuti-
usculis, margine scariosis. Sm.
Gen. Ch a r . Receptacle naked. Pappus margined. Calyx hemispherical, imbricated; the scales somewhat
• acute, with the margin scariose.
Radix annua, subfusiformis, fibrosa.
Caulis plerumque diffusus, usque ad basin ramosus,
subangulatus, glaber, viridis, inferne purpuras-
Folia alterna, sessilia, glabra, pinnata, pinnis lineari-
filiformibus, angustissimis, sub-bipinnatis, apice
acutis, vel non raro mucro'nulatis.
PedunCu l i terminales lateralesque ex axillis foliorum,
' ■ nudi.
Flores majusculi, albi, disco convexo luteo.
Calyx planiusculus, imbricatus, squamis viridibus, gla-
bris, subasqualibus, margine scarioso, fuscescente.
Flosculi radii, ligulati numerosi, patentes, vel etiam re-
flexi, striati, lineari-oblongi, apice obtusissime
tridentati; disci tubulosi, quinque-dentati.
Stamina quinque. Antheras flavas, in tubum coalite.
Germen oblongum, subtriquetrum. Stigma bifidum,
laciniis recurvis.
Semen ( Achenium) oblongum, triquetrum, dorso convexo,
intense fuscum, angulis incrassatis, pallidi-
oribus; pappus margine prominulo, membranaceo,
subintegro.
Receptaculum seminum conico-convexum, puncta-
tum, nudum.
Root annual, somewhat fusiform, and fibrous.
Stem generally diffuse, branched even from the base,
somewhat angular smooth, green, below purple.*
L eaves alternate, sessile, smooth, pinnate, with the
pinnas linear-filiform; very narrow, somewhat
bipinnate, a t the extremity acute, not unfre-
quently mucronulate.
P eduncles terminal and lateral from the axils of the
leaves, naked.
Flowers large, white, with the disk convex and yellow.
Calyx almost plane, imbricated, with the scales green,
smooth, somewhat equal, their margin scariose,
brown.
Florets of the radius ligulate, numerous, patent, or
even reflexed, striated, linear-oblong, at the apex
very obtusely tridentate; those of the disk tubular,
five-toothed.
Stamens five. Anthers yellow, united into a tube.
Ge rm en oblong, subtriquetrous. Stigma bifid, with
the segments recurved.
Se ed ( Achenium) oblong, triquetrous, convex on the
back, deep brown, with the angles incrassated,
of a paler colour; pappus with the margin prominent,
membranaceous, nearly entire.
Receptacle of the seeds conico-convex, punctated,
naked.
% . 1- floret of the radius. Fig. 2 . Floret o f the disk. Fig. 3. Receptacle. Fig, 4. Back view of a seed.
Fig. 5. Front view of ditto. Fig. 6. Seed cut open, to show the embryo—all more or less magnified.
One of the most , common of all weeds in fields and by roadsides throughout the kingdom; flowering up to a very
late period in the autumn (we have seen it in full blossom in the latter end of November), and indeed till the
severe frosts of winter destroy it.
The genera o f Chrysanthemum, Pyrethrum, and Matricaria, border very closely upon each other. To the
present plant the words “ squama acutiuscula ” of the calyx do not apply, for they are decidedly obtuse.
Pyrethrum maritimum is said to differ from P . inodorum in its fleshy leaves, and in the circumstance of the
crown of the seed being lobed. How far these may be sufficient generic marks, we hope at a future time to determine,
this plant, though called inodorum, in opposition to the strong and disagreeable smell of its congeners, is nevertheless
not altogether scentless.
Pyrethrum is an ancient Greek name, and was instituted by Haller, as Sir J. E. Smith tells us, for the present
genus, on account of its resemblance to the Hi>p9Sov of Dioscorides. The latter is however the Anthemis P yrethrum
of modern authors, or Pellitory of Spain; owing its Greek appellation to the fiery or pungent flavour of
he root; whence it also obtained the Latin name of Salimria, because it causes so remarkable a flow o f saliva.