Hawkweed

Foodplant / internal feeder
larva of Ensina sonchi feeds within capitulum of Hieracium umbellatum

Plant / resting place / within
puparium of Melanagromyza dettmeri may be found in stem of Hieracium umbellatum

Foodplant / spot causer
amphigenous colony of Ramularia hyphomycetous anamorph of Mycosphaerella hieracii causes spots on live leaf of Hieracium umbellatum

In Great Britain and/or Ireland:
Foodplant / false gall
larva of Noeeta pupillata causes swelling of capitulum of Hieracium umbellatum

Foodplant / parasite
uredium of Puccinia hieracii var. hieracii parasitises live leaf of Hieracium umbellatum

Foodplant / spot causer
epiphyllous, numerous, covered pycnidium of Septoria anamorph of Septoria mougeotii causes spots on live leaf of Hieracium umbellatum

The circumscription of Hieracium umbellatum adopted here is supported by research done by others, especially G. A. Guppy (1978) and E. Lepage (1960). Hieracium canadense var. kalmii (Linnaeus) Scoggan, referable here, is an illegitimate name.

Plants 15–60+ cm. Stems proximally usually glabrous, sometimes piloso-hirsute and/or stellate-pubescent, distally usually glabrous, sometimes stellate-pubescent. Leaves: basal 0(–2), cauline (5–)8–15(–45+); blades lance-elliptic to lanceolate, (20–)50–100(–150) × (10–)15–25(–40+) mm, lengths (3–)5–10+ times widths, bases cuneate to rounded or truncate (then sometimes ± clasping), margins usually toothed (to laciniate), denticulate, or entire (often ± revolute, at least distally), apices obtuse to acute, faces glabrous or ± stellate-pubescent, sometimes ± scabrellous (especially at or near distal margins). Heads (1–)5–30(–100+) in corymbiform to subumbelliform arrays. Peduncles usually stellate-pubescent. Calyculi: bractlets 9–15+. Involucres campanulate to hemispheric, (8–)9–11+ mm. Phyllaries 12–21+, apices rounded to acute, abaxial faces usually glabrous, rarely piloso-hirsute and/or stipitate-glandular. Florets 30–80+; corollas yellow, 10–18 mm. Cypselae columnar, 2.5–3.5 mm; pappi of 50–60+, stramineous to sordid bristles in ± 2 series, 6–7 mm.

Widespread in temperate regions of the Northern Hemisphere.

2600 m

Hieracium acranthophorum Omang; H. canadense Michaux; H. canadense var. divaricatum Lepage; H. canadense var. fasciculatum (Pursh) Fernald; H. canadense var. hirtirameum Fernald; H. canadense var. subintegrum Lepage; H. columbianum Rydberg; H. devoldii Omang; H. ×dutillyanum Lepage; H. eugenii Omang; H. kalmii Linnaeus; H. kalmii var. canadense (Michaux) Reveal; H. kalmii var. fasciculatum (Pursh) Lepage; H. musartutense Omang; H. nepiocratum Omang; H. rigorosum (Laestadius ex Almquist) Almquist ex Omang; H. scabriusculum Schweinitz; H. scabriusculum var. columbianum (Rydberg) Lepage; H. scabriusculum var. perhirsutum Lepage; H. scabriusculum var. saximontanum Lepage; H. scabriusculum var. scabrum (Schweinitz) Lepage; H. stiptocaule Omang; H. umbellatum subsp. canadense (Michaux) Guppy; H. umbellatum var. scabriusculum (Schweinitz) Farwell

Hieracium umbellatum (commonly called Hieracium canadense), the Canadian hawkweed, Canada hawkweed, narrowleaf hawkweed, or northern hawkweed, is a flowering plant in the family Asteraceae.