Art. LVI.—Notice of the Discovery of Asplenium japonicum, a Fern new to the New Zealand Flora.
[Read before the Auckland Institute, 19th August, 1889.]
So many people take an interest in the ferns of New Zealand, either as collectors or cultivators, that no apology is needed for bringing the discovery of an additional species under the notice of the Institute. Rather more than a year ago Miss Clarke, of Waimate, Bay of Islands, sent for my examination a parcel of specimens of a fern new to her, and which she believed to be new to New Zealand. In this she was perfectly correct, the fern proving to be Asplenium japonicum, a species common enough in many tropical and subtropical countries, but not previously known from New Zealand proper, although in August, 1889, I gathered specimens in a locality as near to us as the Kermadec Islands.
Through the kindness of the Rev. Philip Walsh, of Waimate, Bay of Islands, I have obtained some information respecting the locality in which the fern was found. It formed a patch about 40ft. square in some damp and stony ground on the banks of the Okura River, a branch of the Kerikeri River. The vegetation in the immediate vicinity was chiefly composed of tall tea-tree (Leptospermum), and no plants of any special interest besides the Asplenium were noticed. The neighbourhood was searched for some distance, but no additional specimens were observed.
Asplenium japonicum belongs to the sub-genus Diplazium, hitherto believed to have no representatives in New Zealand. None of the specimens sent to me by Miss Clarke exceeds 18in. in height, and most of them are much smaller. In colour and texture there is some resemblance to Asplenium umbrosum, but that is a much larger fern, with a differently-divided frond. It is quite unlike all the other New Zealand species, and will be recognized with ease should it be found in other localities in the north of the colony, as is not improbable. The following description is drawn up from Miss Clarke's specimens:—
Rhizome slender, apparently long and creeping. Stipes slender, pale, with a few chaffy scales at its base, 4in.–8in. long. Frond 6in.–9in. long, 3in.–5in. broad, ovate-lanceolate, pinnate at the base, pinnatifid towards the top; pinnæ ¾in. broad, cut down nearly to the rachis in the lower part; lobes oblong, rounded, toothed; texture herbaceous. Veins 3–6 to a lobe on each side, usually all soriferous. Sori occasionally diplazoid.
Originally discovered in Japan, hence its name of japonicum. It has since been found to be widely spread through Eastern Asia, ranging from Japan and China to India and Malacca. It also occurs in several of the islands of the Malay Archipelago, in New Guinea, and has been recorded from Fiji and Samoa and others of the Polynesian islands.