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

SONCHUS L.

Annual to perennial herbs, taprooted or roots creeping and perennating. Tomentum generally confined to infls, or 0, composed of fine tangled and branched and/or long glandular or eglandular hairs. Stems usually branching above. Lvs basal and cauline, undivided to 1-(2)-pinnatifid. Capitula terminal and axillary, pedunculate, sometimes ± umbellate. Involucral bracts usually with tangled short white branching hairs, often with longer glandular or eglandular hairs, rarely glabrous; outer bracts small; inner bracts becoming larger, not in distinct rows. Receptacle mammillate, glabrous or with small scales or fine hairs. Corolla ligulate, yellow, or ligule pinkish beneath. Style branches filiform, dark. Achenes brown, numerous, weakly or strongly flattened, 3-5-ribbed on each face, winged or not; beak 0; pappus > achene, soft, white; bristles of 2 types, both scabrid: fine hairs with 2-fid apices, and very fine hairs with numerous microscopic recurved barbs at apices.

Key

1
Achenes strongly flattened and winged, with 3 principal ribs on each face, smooth between the ribs
2
Achenes weakly compressed, not winged, with 3 or 5 principal ribs on each face, rugose or wrinkled on and between the ribs
3
2
Taproot swollen above; lvs glaucous, dull, thick, dentate but not spinous; coastal, mostly on cliffs
4. kirkii
Taproot not swollen; lvs usually green, rarely glaucous, ± shiny, firm-textured, sinuate-dentate with prickly-spinose teeth; mostly a weed of disturbed sites, sometimes coastal
2. *asper
3
Annual with tap and fibrous roots only; achenes finely rugulose, 3-ribbed on each face; involucre < 15 mm long, the outer bracts glabrous or rarely with a few pale glandular or eglandular setae
3. *oleraceus
Perennial with creeping perennating roots; achenes rugose, 5-ribbed on each face; involucre 15-18 mm long, the outer bracts with numerous conspicuous yellow glandular setae
1. *arvensis

55 spp., cosmopolitan, especially Africa and Europe. Native sp. 1, naturalised 3.

The most recent revision of Sonchus is that of Boulos, L., Bot. Not. 125 : 287-305 (1972); ibid. 126 : 155-196 (1973); ibid. 127 : 7-37 (1974).

The Maori name puha or puwha is applied to Sonchus spp. Achenes of all spp. are illustrated in Fig. 37.

Fig. 37. Sonchus, achenes. A S. kirkii; B S. asper; C S. oleraceus; D S. arvensis. © All rights reserved. [Image: 4X4V]
Fig. 37. Sonchus, achenes. A S. kirkii; B S. asper; C S. oleraceus; D S. arvensis. © All rights reserved. [Image: 4X4V]
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