Art. XLIX.—Description of a New Native Grass.
[Read before the Auckland Institute, 9th October, 1905.]
Poa astoni, sp. nov.
A grass growing on coast cliffs, densely tufted, 15 in. high or less, with leaves equalling or exceeding the culms. Leaf-sheaths broad, compressed, thin, striate, glabrous, pale, continued at the edges and front into a rigid broadly triangular acute ligule. Leaf-blades filiform, involute, striate, glabrous, suddenly narrowed from the back of the sheath, the point of origin being marked by a joint; in age deciduous at the joint. In smaller forms the blades are shorter, more rigid, and almost acicular. Culms slender, few-jointed, striate, the joints short and constricted; uppermost leaf on culm long-sheathing. Panicle ovate or ovate-oblong, compact, 2½ in. long or less; panicle-branches 4 or fewer, terete, glabrous, swollen below the insertion of the spikelets. Spikelets crowded at the tips of the panicle-branches, pale, shining, shortly stalked, ¼ in. long, 5–6-flowered, flowers all sessile. Outer glumes half as long as the spikelets, pale and shining, nearly equal, broadly lanceolate, acuminate, glabrous, 3-nerved for two-thirds of their length. Flowering-glumes glabrous or finely pubescent, strongly 5-nerved, acuminate, the midrib delicately scabrid or almost glabrous, ciliate at the margins, with a scanty tuft of long hairs at the bottom of the back; this tuft sometimes absent. Palea 2-nerved, nerves ciliate, bifid at the top.
Hab. Rocky cliffs and reefs on the coast of Otago and Stewart Island—at Brighton, Taieri Mouth, Catlin's River, Waikawa, Bluff, and Paterson's Inlet; also at the Auckland Islands (fide T. Kirk, who contributed specimens from there to Mr. Cheeseman's herbarium).
Sir J. D. Hooker's Festuca scoparia, described in the “Flora Antarctica,” appears to include two distinct grasses, the present grass and one that is confined to the southern off-islands, where it forms the principal coastal and upland tussock-grass on the Auckland, Campbell, and Antipodes Islands. As many of the characters contained in Hooker's description apply only to the latter, I conclude that it was the off-island tussock-grass that be meant to distinguish as Festuca scoparia.
Hackel recognised that Festuca scoparia was a true Poa. Cheeseman, who agreed with this view, has accordingly named
it Poa litorosa, the name Poa scoparia being preoccupied. I assume that Poa litorosa is the off-island grass, which is not known to extend to the main islands of New Zealand, and cut out of Hooker's original species, the one here described.
I formerly referred specimens of the true Poa litorosa, Cheesm., given to me by the late Mr. T. Kirk, F.L.S., under the name of Festuca scoparia, Hook. f., and collected by him on the Auckland Islands, to my Poa chathamica. This mistake was due to misunderstanding the true relations of Poa litorosa, Cheesm., and the species here described.
An accurate description of Poa litorosa is much needed, but at present the material in the possession of colonial botanists is insufficient for the purpose.