Art. XXVI.—The rediscovery of Ranunculus crithmifolius Hook f.
[Read before the Philosophical Institute of Canterbury, 7th December, 1910]
In the “Handbook of the New Zealand flora (1864), by Sir J. D. Hooker, there is described as a new species Ranuncullus crithmifolius. It was collected by Mr. W. T. L. Travers at the Wairau Gorge, at an altitude of 6,000 ft. Hooker ads to his description the note that it is “a very singular plant, easily recognized by its glaucous, fleshy havit, finely divided leaves, and single-flowered short scapes.” Mr. T. Kirk, in his “Students' Flora of New Zealand” (1899), quotes Hooker's description, and adds—I know not on what authority—the remark that only one specimen of the plant was found by Travers. In Cheeseman's “Manual of the Zew zealand Flora” (1906), under the description appears the note, “A curious little plant, which has not been collected since its original discovery nearly forty years ago. Ther are no specimens in any of the New Zealand herbaria, and I have consequently reproduced Hooker's description.”
In the “Plants of New Zealand,” 1906, p. 170, alluding to this plant, wrote thus: “In spite, however, of all the perseverance and research of modern workers, a few of the forms apparently known to the earliest explorers have not been rediscovered in recent times. In some cases it is probable that the plant has been redescribed under a fresh name; in a very few cases it may be that on account of its extreme rarity has never been seen againg. In Ranunculus crithmifolius we have a plant that has not been reidentified since first found by Travers on the shingle-slips of the Wairau Gorge. Even then only a single plant was seen. It seems more than likely, therefore, that the plant was a casual variant of some other form than really a distinct species. If, however, the original description is to be trusted, Ranunculus crithmifolius is one of the most remarkable species of the genus. Like all other shingle-slip plants, it is highly specialized; otherwise it would not have been able to live in the place whence it was reported… It has leaves which, on a smallerscale, closely resemble those of the rock-samphire, a plant of an altogether different order. They are thick, succulent, bluish-green, and highly polished, thus differing widely from the normal leaf-form of the genus. Diels compares them to the leaves of Ligusticum carnosulum, which is one of the most singular species of the flora, and also [along with Ranunculus Haastii] grows on the same shignle-slips in the Wairau Gorge.”
carnosulum, and although Ranunculus Haastii was not seen on the same shingle-slip it is to be found in the district. A careful search revealed scapes that had done flowering and showed the plant to be a Ranunculus, and on taking it back to camp it was found to agree in every detail with Hooker's description of Ranunculus crithmifolius. It is strange that a plant which had been lost for nearly fifty years should be obtained about a hundred and fifty miles away from its first-discovered habitat, but still in association with the same species originally found in its vicinity. A long search failed to reveal any flowers, and only a few achene-bearing plants were found.
A little needs to be added to the original description. Some living specimens were obtained, and one or two of these were given to Mr. J. R. Wilkinson, of Bushside, Mount Somers. He has been able to grow them, and forwarded me, on the 20th September of this year, a fully expanded flower. I am thus able to give a more complete description of the plant than has hitherto been possible, for Travers's specimen was in fruit only.
a, b. Leaves; half natural size.
c. Plant; half natural size.
d. Flower, from front; half natural size.
e. Flower, from back; half natural size. One sepal has become leaflike.
f. Fruit; magnified twice.
The horizontal rootstock, which is about 1 cm. in diameter, sends out at intervals loose rosettes of 6–8 leaves, which die down in the autumn. When mature the leaves are 6–10 cm. high, and of the usual grey-green of the plants of the shingle-slip. The petioles are 5–7 cm. long, channelled, and end in a somewhat membranous yellow-brown leaf-sheath, about 2 cm. in length. The leaf is usually ternately divided, the petiolule about equalling the blade in length. The latter is more or less triangular in outline, and
3–4 cm. broad at the base. The secondary segments are pinnately rather than ternately subdivided, and are also more or less triangular in outline. The ultimate divisions are linear, obtuse, 2–3 mm. long, and about 1 mm. broad. At Mount Somers the plant flowered in September, while the leaves were still unfolded and closely appressed to the shingle. * The scape is short, 1–2 cm. long; flowers 2–3 cm. in diameter. Sepals (5) oblong, inbricate in the bud, pale cream, truncate, 8–10 mm. long, tinged on the under-surface with pale brown. Petals (5) cuneate, slightly emarginate, yellow above, streaked with brown below, with a single large glandular pit at the base of each. When the flower is fully expanded the petals are remote, and admit the full breadth of the sepals between them. Stamens numerous, filaments short, about half the length of the petals. The turgid achenes, about 12–20 in number, form a rounded head 8–10 mm. in diameter. All parts of the flower are quite glabrous.
Though no original specimens have been seen, the identity of the plant with that of Travers can scarcely be doubted. I have deposited a specimen in Canterbury Museum.
[Footnote] * Since writing the above I have seen specimens of the flower in Dr. Cockayne's garden in Christchurch. On my return to Christchurch last January I gave him one or two living plants of R. crithmifolius. These have grown quite readily in ordinary soil at the low altitude of Christchurch. The leaves are less appressed to the surface of the ground and the scapes are much longer than in the specimen grown by Mr. Wilkinson.