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Volume V (2000) - Flora of New Zealand Gramineae
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Agrostis L.

Agrostis L., 1753

Type species: Agrostis canina L.

Annuals or perennials, tufted, or widely creeping and rhizomatous or stoloniferous. Leaf-sheath rounded. Ligule membranous. Leaf-blade flat or involute. Culm of various height, erect, or decumbent and geniculately ascending; nodes glabrous. Inflorescence a diffuse and often delicately branched or contracted panicle, sometimes spike-like, rarely much reduced and hidden among leaves; rachis persistent at maturity. Spikelets small, numerous to few, 1-flowered; disarticulation above glumes; rachilla usually not prolonged. Glumes equal to subequal, lanceolate, acute to acuminate, sometimes subobtuse, membranous, shining, 1-nerved, keel ± scabrid. Lemma usually < glumes, thinner in texture than glumes, hyaline to firmly membranous, broadly ovate, usually truncate to dentate, rounded, 3-5-(7)-nerved with nerves sometimes excurrent, awnless or with a dorsal awn. Palea hyaline, 2-keeled or nerveless, usually < lemma, sometimes very small or obsolete, almost covered by inrolled margins of lemma. Callus short or minute, blunt, glabrous, or with ± minute lateral tufts of hairs. Lodicules 2, lanceolate, hyaline. Stamens 3. Ovary glabrous; styles distinct, free to base, short; stigmas 2, plumose. Caryopsis ovoid or fusiform, ± dorsally compressed, longitudinally grooved or rarely terete; embryo small; hilum punctiform or elongate; endosperm sometimes liquid. Chasmogamous (N.Z. spp.).

Key

1
Palea c. ⅓ length of lemma or shorter (indigenous)
2
Palea ½-⅔ length of lemma (naturalised)
13
2
Panicle contracted with branches hidden, narrow-linear, or densely oblong to lanceolate, or a minute (< 7 mm) dense ovate head
3
Panicle loose and often spreading with obvious branches, ovate to pyramidal or laxly oblong to lanceolate, never contracted to a dense head
9
3
Lemma awn 3 mm or longer; spikelets 3.5-5 mm
6. magellanica
Lemma awnless, or with awn 0.5-2-(2.5) mm; spikelets < 3.3 mm, rarely to 4 mm
4
4
Panicles all < 4.5 cm
5
Panicles all, or at least some, > 4.5 cm
7
5
Plant forming rounded cushions or mat-like patches; panicle < 0.7 cm; leaves usually reflexed
8. muscosa
Plant forming ± stiff tufts; panicle 1-4.5 cm; leaves ± erect
6
6
Glumes finely scabrid on keel and sometimes near tip, otherwise smooth or papillose, usually tinged deep reddish purple, occasionally entirely green
7. muelleriana
Glumes minutely pubescent-scabrid except near base, light green, very rarely light purple-tinged
14. subulata
7
Panicle 2-3 mm wide
5. imbecilla
Panicle > 5 mm wide
8
8
Panicle oblong; lemma 1.4-2 mm
7. muelleriana
Panicle lanceolate; lemma 2.3-3.3 mm
3. dyeri
9
Leaf-blade strictly involute, wiry, abaxially very densely scabrid-papillose throughout; anthers 1.3-1.8 mm, rarely c. 1 mm
12. petriei
Leaf-blade flat or folded, or filiform-involute, not wiry, abaxially smooth, but scabrid near tip, or on nerves or very rarely throughout if flat; anthers 0.4-1.2 mm
10
10
Lemma 2.3-3.3 mm; spikelets usually 3-3.5 mm, rarely to 4 mm
3. dyeri
Lemma 1.2-2-(2.2) mm; spikelets usually 1.5-2.5 mm, rarely to 3 mm
11
11
Branching intravaginal at base; lemmas all awned; ligule abaxially smooth
9. oresbia
Branching extravaginal at base; lemmas awnless, or occasionally awned and then ligule abaxially finely scabrid
12
12
Tufts 6.5-30-(60) cm; panicle (2)-4.5-8.5-(16) cm; spikelets usually 2-2.5 mm; glumes acute, > lemma
11. personata
Tufts 3-5-(20) cm; panicle 0.6-2-(3) cm; spikelets usually 1.5-2 mm; glumes subobtuse, usually ≈ lemma
10. pallescens
13
Ligule 0.6-2 mm, shorter than wide; plants tufted or very shortly rhizomatous or stoloniferous; lemma usually 3-nerved
1. capillaris
Ligule 0.7-6 mm, taller than wide; plants long-rhizomatous or with long stolons; lemma usually 5-nerved
14
14
Plant with long stolons; panicle contracted after flowering, 0.5-2.5 cm wide
13. stolonifera
Plant long-rhizomatous; panicle remaining open and lax, or if contracted after flowering, then 4-8 cm wide
15
15
Leaf-blade 3-8 mm wide, bright green; panicle usually pyramidal, always very lax; spikelet pedicels always closely scabrid
4. gigantea
Leaf-blade 1.5-4 mm wide, grey-green; panicle usually linear-lanceolate, often contracted after flowering; spikelet pedicels glabrous to ± scabrid
2. castellana

c. 220 spp. of temperate regions throughout the world and in the tropics at high altitudes. Endemic spp. 8, indigenous spp. 2; naturalised spp. 4.

N.Z. spp. of Agrostis were revised by Edgar, E. and Forde, M. B. N.Z. J. Bot. 29: 139-161 (1991), with an assessment by M. B. Forde of the extent and taxonomic significance of hybridism among naturalised bent grasses.

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