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(b.) Historical.
Senecio saxifragoides was first described by Hooker in 1853 (Flora Novae-Zelandiae, vol. 1, p. 144), and in the Handbook its discovery is accredited to Lyall (Handbook, p. 159).
Hooker, Kirk (Students' Flora, p. 339), and Cheeseman (Manual, p. 372) agree in describing S. saxifragoides as distinguished from S. lagopus only in respect of the leaf, which is described as “clothed with shining silky and woolly hair “(Hooker), “silky or villous” (Kirk), “silky or villous” (Cheeseman), upon the upper surface only, and wanting the stout bristle which characterizes S. lagopus and S. bellidioides. Kirk says, “The leaves are often glabrous or glabrate on the upper surface, but never bristly as in S. lagopus.” Cheeseman says, “A handsome species, separated from large states of S. lagopus, some of which approach it very closely, by the much stouter habit, more copious villous hairs, and larger thicker leaves, which are silky above and never show the stout bristly hairs so characteristic of S. lagopus and S. bellidioides.”
All agree that these three species, S. lagopus, S. bellidioides, and S. saxifragoides, are very closely allied. Hooker (Handbook) says, “This [S. lagopus] and the two following [i.e., S. bellidioides and S. saxifragoides], though most dissimilar in their usual states, appear to me to be united by intermediate forms,” and (Flora Novae-Zelandiae), “This and the two following are closely allied and very singular species.”
The distribution of S. saxifragoides is given by Hooker as “Port Cooper”; by Kirk as “Port Lyttelton, Banks Peninsula”; and by Cheeseman as “Port Lyttelton and other localities on Banks Peninsula.”
All agree in describing the leaf of S. saxifragoides as broader or more nearly orbicular than that of S. lagopus; but they do not quite agree as to the relative size. Hooker makes the leaf of S. lagopus 2 in. to 4 in. long (!); that of S. saxifragoides 3 in. to 5 in. long. Kirk makes the leaf of S. lagopus 1 in. to 8 in. long (excluding the petiole), and that of S. saxifragoides 3 in. to 6 in. long. Cheeseman makes the blade of S. lagopus 1 in. to 5 in. long, and that of S. saxifragoides 3 in. to 6 in. long. Raouls description of S. lagopus (Choix, p. 21) gives the leaf about 1 decimetre (4 in.) long and from 7 to 9 centimetres (3–3 ½in.) broad. Hooker's and Raoul's descriptions would seem to have been based upon comparatively small specimens of both species.
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The distribution of S. lagopus is given by all authorities as from the Ruahine Mountains to South Canterbury.
The original description of S. lagopus by Raoul, and his plate (Choix, pl. 17), must here be referred to, as of the greatest importance in the study of the two species. In describing the petiole of S. lagopus, Raoul says, “Petioli … canaliculati in vaginam semiamplexicaulem dense lanatam dilatati “; and in describing the leaf he says, “Folia … pilis rigidis grossis, spinescentibus praesertim ad. margines inspersa.” His plate shows a plant with four large and several small leaves. Of the four large leaves three are glabrate (as the old leaves of both S. lagopus and S. saxifragoides always are): the fourth bears the characteristic “bristles” very thickly close to the margin all round the leaf, or nearly so; and near the apex; less thickly upon the upper third of the leaf or thereabout; the lower part of the leaf bears the hairs only, very thickly distributed. The hairs and bristles occur together over some portions of the leaf, about the middle and towards the apex, but at the apex itself and in its immediate neighbourhood the bristles alone occur. The dual occurrence of hair and bristle* on the same leaf, which no subsequent authority describes at all, will appear to be of great importance to this inquiry; and it may be added that my descriptions of the variant forms of S. saxifragoides given below were fully made before I had seen Raoul's plate.
The species are further thus referred to by-Laing and Blackwell (Plants of New Zealand, pp. 437–38, 1906): “The handsome S. saxifragoides, sup posed by Kirk to be confined to Banks Peninsula, is undoubtedly the typical S. lagopus of Raoul. It still produces its large-leaved rosettes on the southern faces of cliffs, where Raoul found it, near Akaroa. It is also plentiful behind Lyttelton, often growing in altogether inaccessible localities, and it is the only Senecio which haunts these situations on the Peninsula.”
[Footnote] * The term “bristle” is kept throughout, as that employed by previous authorities though the organ is really a glandular hair.