Art. XLII.—On the New Zealand Forms of Cheilanthes.
[Read before the Auckland Institute, 4th August, 1873.]
While recently waiting at Lyttelton for the departure of the steamer, in company with Mr. S. C. Farr, I took the opportunity of examining the rocks in the immediate vicinity, when we had the good fortune to find a tuft or two of the typical form of Cheilanthes tenuifolia, Swartz, a plant new to me, and offering a marked contrast to C. sieberi, Kunze, which is so abundant amongst the scoria in the neighbourhood of Auckland, and in other localities in the North Island. I ascertained that the same plant had been collected by Mr. Potts on another part of Banks Peninsula, and Mr. Farr informed me that he had seen it in other places; but I am not aware of its having been noticed in the colony by other observers since its first discovery by Dr. Lyall, possibly on the spot where it was seen by us, and where it grows associated with the handsome Senecio saxifragoides.
The only positive statements I can find of the occurrence of our plant in New Zealand are under the description of the species in “Species Filicum” (Vol. II., p. 82), where it is recorded by Sir William Hooker as having been found on Banks Peninsula by Dr. Lyall; and in “Synopsis Filicum,” where it is simply stated to be a native of New Zealand. In the “Flora of New Zealand” Dr. Hooker uses the name C. “tenuifolia,” Swartz, but remarks, “the figure of C. sieberi in ‘Species Filicum’ resembles the New Zealand plant;” although from his describing the frond as “rarely deltoid,” he doubtless had Dr. Lyall's specimens before him. In the Handbook, after describing, at p. 362, the ordinary New Zealand plant as C. tenuifolia, var. sieberi, Dr. Hooker remarks, at page 748, “This is usually kept as a distinct species—C. sieberi, Kunze.” It is probably from this cause, coupled with its rarity in the colony, that New Zealand botanists have so completely lost sight of our plant, that no mention of it was made in the Catalogue of Ferns issued by the Geological Survey Department two or three years ago. I may add that I have no knowledge of any specimens in local herbaria, except those to which reference is now made.
C. tenuifolia, Swartz, and C. sieberi, Kunze, are considered distinct by Mr. Baker in “Synopsis Filicum,” but are certainly of close affinity. Still the difference in the appearance of the two forms, together with the remarkable localization of the first-named, render it desirable that the attention of New Zealand botanists should be drawn to the re-discovery of our plant.
At first sight C. tenuifolia is easily recognized by its deltoid fronds and long ascending pinnules; C. sieberi by its narrow, almost lanceolate fronds, and
short pinnules. I have drawn up the following diagnosis of cach, which differs slightly from those of “Synopsis Filicum.”
Cheilanthes tenuifolia, Swartz.
Rhizome covered with silky scales. Stipes tufted, erect, 4″–6″ long, wiry, polished, purple black, slightly fibrillose at base. Frond 6″–8″ long, 3″–4″ broad, deltoid tripinnatifid, glabrous, not coriaceous. Pinnæ 6 to 12, ascending at an acute angle with the main rachis in nearly opposite pairs, or alternate. Pinnules deltoid or oblong, contracted, cut down to the rachis in deltoid or oblong, entire or irregularly-lobed, or crenate, or rounded segments. Rachis narrowly winged above, polished, smooth, glabrous on both surfaces. Sori often continuous, covering the back of the pinnule, and projecting beyond its margin. Involucre crenate or toothed.
Cheilanthes sieberi, Kunze.
Stipes densely tufted, 2″–6″ long, erect and crowded, wiry, polished, brown. Frond 3″–9″ long, ¾″–1 ½″ broad, narrow-oblong-lanceolate, acuminate, tripinnatifid. Pinnæ in 3 to 15 opposite pairs, lower pairs distant, broadly deltoid, ¾″–1″ long. Pinnules pinnate at base, not coriaceous. Segments entire, or lobed, or crenate, often contracted. Sori scattered, rarely continuous, and never projecting beyond the margin of the pinnule. Involucre small, roundish, not apparently toothed.