Volume IV (1988) - Flora of New Zealand Naturalised Pteridophytes, Gymnosperms, Dicotyledons
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Hieracium L.

HIERACIUM L.

Perennial rhizomatous herbs; stolons present or 0. Hairs stellate, plumose, simple and eglandular, and glandular, in various proportions. Stems branching or scapose. Lvs simple, usually toothed, usually basal and cauline, or all basal, sometimes basal rosette 0. Capitula solitary or paired or in lax to compact cymes or corymbose panicles. Involucral bracts narrowly triangular to linear, usually hairy; outer bracts < inner; inner bracts in several imbricate series. Receptacle areolate, the margins of areoles glabrous and usually dentate or fimbriate; scales 0. Corolla ligulate, usually yellow, rarely orange, sometimes with red or pink stripe on outer face. Style branches filiform, yellow or discoloured. Achenes numerous, dark, cylindric, 10-ribbed, not beaked; pappus bristles in 1 row or partly in 2 rows, usually dirty white, > achenes, often unequal, simple, free at base.

SYNOPSIS

may be neatly divided into several subgenera although arguments for accepting these at generic rank are not all convincing. Two of these, subgen. and subgen. , are represented in N.Z.:

  • A. Subgen. Hieracium. 
    • Mostly obligate apomicts. Stolons 0. Lvs entire to deeply dentate; at least the basal lvs usually petiolate. Achenes 3-5 mm long, the ribs apically confluent into an obscure ring. Pappus partly in 2 rows, the hairs unequal:
    • 1. *argillaceum group 4. *lepidulum 5. *murorum 7. *pollichiae 9. *sabaudum
  • B. Subgen. Pilosella. 
    • Plants sexual or partly apomictic. Stolons usually present. Lvs entire to slightly denticulate; petiole 0 or indistinct. Achenes up to 2.5 mm long, the ribs shortly protruding to give a crenulate apex to the achene. Pappus strictly in 1 row, a few hairs much < the others:
    • 2. *aurantiacum 3. *caespitosum 6. *pilosella 8. *praealtum 10. *× stoloniflorum

Key

1
Stolons usually present; lvs entire or very obscurely toothed; achenes < 2.5 mm long
2
Stolons 0; lvs usually distinctly toothed; achenes 3-5 mm long
6
2
Ligules orange, purple when dry
3
Ligules yellow, often with a red stripe on outer face
4
3
Capitula (3)-5-10-(15) per stem, on peduncles 1-2 cm long at flowering; involucre 5-8-(10) mm long; lvs without stellate hairs or with scattered stellate hairs especially about midrib beneath
Capitula solitary or paired on peduncles > 3 cm long at flowering; involucre c. 10 mm long; lvs with numerous to dense stellate hairs beneath
4
Capitula solitary; lvs with very dense tomentum of stellate hairs beneath
Capitula (1)-3 or more per stem; lvs with 0-numerous stellate hairs beneath
5
5
Lvs green with fine hairs 1-2-(3) mm long scattered over both surfaces (rarely glabrous above) and few to numerous stellate hairs beneath
Lvs ± glaucous with setose hairs 2-4 mm long scattered or 0 on upper surface and 2-5 mm long confined to midrib and margins beneath; stellate hairs 0 or a few on midrib beneath
6
Basal lvs withering during anthesis; stem lvs > 20, with truncate to amplexicaul base
Basal lvs present at anthesis; stem lvs < 6, with cuneate base
7
7
Involucral bracts with sparse to numerous simple pale-tipped eglandular hairs (stellate and dark glandular hairs also present)
8
Involucral bracts without simple eglandular hairs (stellate and dark glandular hairs present)
9
8
Lvs green with purple streaks on upper surface; stellate hairs 0 on upper surface of lvs
Lvs uniformly green on upper surface; stellate hairs present on upper surface of lvs
9
Basal lvs truncate, with spreading to reflexed basal teeth; stem lvs 1-(2); lvs without stellate hairs
Basal lvs cuneate, with ascending basal teeth; stem lvs (1)-2-4-(6); stellate hairs rarely 0 on lvs, usually present at least beneath

c. 1000 spp. (or c. 5000 spp. if apomictic microspp. included), temperate regions (except Australasia) and tropical mountains. Naturalised spp. 9 and 1 hybrid.

African spp. sometimes included in Hieracium may be better placed in Tolpis, and S. American spp. in Crepis, according to Sell, P. D. and West, C., in Fl. Turkey 5 : 697 (1975).

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