1.
Tussilago farfara
Linnaeus, Sp. Pl. 2: 865. 1753.
Coltsfoot
Basal leaves:
blades palmately 5—12-lobed or -angled, mostly 5—20+ × 5—20+ cm, margins irregularly denticulate.
Cauline leaves
mostly 5—25 mm.
Calyculi:
bractlets 5—15 mm.
Phyllaries
mostly 7—15 mm.
Ray corollas:
laminae (2—)4—10 mm.
Disc corollas
10—12 mm.
Cypselae
3—4 mm;
pappi
8—12 mm, ± surpassing involucres.
2
n
= 60.
Flowering spring—summer. Disturbed sites, sandy or rocky soils, calcareous sites; 0—800 m; introduced; Saint-Pierre and Miquelon; B.C., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que.; Conn., Ill., Ind., Maine, Md., Mass., Mich., Minn., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., Tenn., Vt., Va., Wash., W.Va., Wis.; Eurasia.
Flowering heads of
Tussilago farfara
close at night (laminae of ray corollas arch and roll inward). The species is becoming an invasive weed in some areas.
