Flora of New Zealand Series

≡Agrostis lyallii Hook.f., Fl. N.Z. 1: 297 (1853)

≡Deyeuxia forsteri var. lyallii (Hook.f.) Hack. in Cheeseman Man. N.Z. Fl. 869  (1906) comb. illeg., varietal epithet legit.; 

Holotype: K! Dr Lyall Milford Sound, New Zealand.

=D. forsteri var. semiglabra Hack. in Cheeseman Man. N.Z. Fl. 869  (1906) comb. illeg., varietal epithet legit.

≡Lachnagrostis filiformis var. semiglabra (Hack.) Zotov, Rec. Dom. Mus. 5: 142 (1965); 

Holotype: AK 1449! T. F. C[heeseman] Broken River, Canterbury Alps, 2000 ft (No 1131 to Hackel).

Lax, sometimes stoloniferous, perennial tufts, (5)-10-50 cm, with wide, flat, or narrow and folded, light or dull green leaves, and lax panicles often large in proportion to the plant; branching extravaginal; short plants with narrow involute leaves may be more densely tufted. Leaf-sheath submembranous, distinctly ribbed, smooth, or minutely scabrid above, green to creamy brown, sometimes purplish. Ligule 0.6-4 mm, ovate-oblong, ± truncate, denticulate to later ± lacerate, abaxially minutely scabrid. Leaf-blade 2-15 cm × 0.3-3.5-(6) mm, flat or folded, abaxially smooth to finely scabrid on ribs throughout or near tip, adaxially finely scabrid on ribs; margins minutely scabrid, tip subacute. Culm 3-25-(45) cm, erect or geniculate at base, longer culms projecting beyond uppermost sheaths, internodes usually finely scabrid below panicle. Panicle 4-25 × 1-16 cm, very lax or sometimes contracted after flowering, with widely spreading, finally horizontal branches; branches rather few, very finely, ± sparsely scabrid, with 1-2-several spikelets at branchlet-tips. Spikelets 2.3-4.5-(5) mm, pale green to light straw-coloured, greenish brown or purplish. Glumes subequal, ovate-elliptic or narrowly elliptic-lanceolate, acute, midnerve and hyaline margins scabrid near tip or in upper ½. Lemma (1.5)-2-2.5-(2.8) mm, ½-¾ length of glumes, 5-nerved, with numerous to scattered short fine hairs, sometimes almost completely glabrous, or the upper ⅓ ± glabrous, elliptic-oblong, truncate, lateral nerves slightly to obviously excurrent; awn (1.7)-2-6 mm, geniculate, ± middorsal. Palea c. ½ length to ≈ lemma, keels very faint, 0.1-0.2 mm apart, apex truncate, or obtuse, or shallowly notched. Callus hairs moderately dense, to 1 mm, to ⅓ length of lemma. Rachilla prolongation 0, or up to 1 mm, tipped by a few equally long, or longer hairs. Lodicules 0.7-0.9 mm, linear, acute. Anthers (0.3)-0.6-1.2-(1.5) mm. Caryopsis 1.2-2 × 0.4-0.8 mm. Plate 6B.

N.: one collection from Kaihu (north of Dargaville) and south from East Cape, Rotorua and Kawhia Harbour; S.: throughout; Ch. Open ground in tussock grassland and in other open sites; lowland to alpine.

Endemic.

In many specimens of L. lyallii there is no rachilla prolongation but it can be well-developed in others; in CHR 285393 M. J. A. Simpson 7326 The Monument, Banks Peninsula, some rachillas were tipped by a rudimentary second floret.

Two forms can be distinguished within L. lyallii. Plants throughout North Id and in northern South Id are lax, with flat leaves, spikelets c. 4-5 mm, the lemma often almost glabrous c. 2.5 mm, the palea c. ½ the length of the lemma and the anthers usually 0.8-1.2 mm. The type of Deyeuxia forsteri var. semiglabra belongs here. In central North Id and in South Id, especially in southern and western regions, plants have inrolled leaves, smaller spikelets c. 2.5-3.5 mm, smaller, more densely hairy lemmas c. 1.8-2.2 mm, with the palea c. ¾ to ≈ lemma and anthers often rather short (0.3)-0.6-0.8 mm. In inland central to South Canterbury and in Otago, plants are small and densely tufted, but in western areas plants with inrolled leaves are taller and more lax, as in the type of L. lyallii. However no satisfactory geographical separation can be found, and it is even more difficult to separate the forms morphologically because so many intermediates occur.