Senecio skirrhodon DC.
gravel groundsel
Ascending, annual or short-lived perennial herb, 15-50 cm tall. Stems glabrous, much-branched above and below, sometimes becoming ± leafless and woody toward base. Cauline lvs usually glabrous or with scattered hairs on midvein below and ciliate at base, apetiolate (cuneately narrowed to short petiole in lowermost lvs), fleshy, pale to mid green, oblanceolate to narrow- obovate, mostly entire and slightly involute, sometimes serrulate and often some lvs serrate or pinnatisect with 2-4 incisions on each side, acute and mucronate, cuneate to amplexicaul base, 20-60 × 2-10-(15) mm; venation palmate. Uppermost lvs smaller, often lanceolate and more often amplexicaul. Capitula solitary or few in corymbs. Supplementary bracts 9-17, narrow- triangular, 2-3 mm long. Involucral bracts 18-23, linear, glabrous, 5-7 mm long. Ray florets 11-16; ligules bright yellow, (5.5)-7-13 mm long. Disc golden yellow. Achenes subcylindric, constricted below apex, usually with (2)-3-(6) rows of hairs in grooves between broad ribs, sometimes glabrous, 1.6-2.2 mm long; pappus 3-5 mm long.
N.: Whangarei, vicinity of Auckland, Tauranga, Waikato, vicinity of Napier, Palmerston North, coastal Wellington Province; S.: Westport, vicinity of Christchurch, Dunedin.
Madagascar, and from Mozambique to South Africa 1920
Coastal sites, waste places, inland mainly as a weed of railway lines, yards and ballast.
FL Dec-Jan.
Possibly poisonous (Connor 1977).
This African sp. has always been incorrectly identified in N.Z. as S. spathulatus, an Australian member of the S. lautus complex. S. skirrhodon differs from plants referred to S. lautus and S. spathulatus in Australia by the more numerous involucral bracts, and from some Australian populations by the shorter achenes. N.Z. material of S. skirrhodon exactly matches some African material, but the sp. is less variable in N.Z.; in particular lvs of N.Z. plants are often entire or have few teeth whereas many African collections have finely serrate lvs. S. skirrhodon differs from S. lautus in N.Z. by the more numerous involucral bracts, longer rays, and less divided lvs. In Africa, as in N.Z., coastal plants in this group of senecios have more fleshy lvs than inland forms, and Hilliard, O. M., Compositae in Natal (1977), noted that S. skirrhodon is possibly no more than a maritime form of S. madagascariensis Poiret but nevertheless treated it at sp. rank. S. madagascariensis is naturalised in Australia and is poisonous.
