Sorghastrum nutans (L.) Nash
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TAXONOMY
 
Family: Poaceae
Genus: Sorghastrum
 
Species Synonyms: Andropogon nutans L.
Sorghastrum avenaceum (Michx.) Nash
Common Names: yellow Indian-grass
wood grass
 
DISTRIBUTION
 
Canada: southeastern Saskatchewan – southern Manitoba, southern Ontario – southern Quebec
Saskatchewan: southeastern Saskatchewan; Souris River Valley
Ecoregion: Moist Mixed Grassland
 
HABITAT
 
Saskatchewan: sandstone outcrops and south-facing grassland slopes of river valley bluffs
Associated Species: big bluestem, little bluestem, prairie goldenrod, switchgrass, wild licorice
 
RARITY STATUS
 
Provincial Status According
to Harms (2003):
Endangered
Nature Conservancy Status:
G5 S3
Saskatchewan Species at
Risk Status:
None
COSEWIC Status:
None
 
Yellow Indian-grass is endangered because it is extremely rare in Saskatchewan and is restricted to a small area of the province. It is almost always locally sparse. Immediate or probable threats have been identified.
 
SPECIES DESCRIPTION
 
Height: 50 – 240 cm
Roots: roots fibrous; rhizomes long to short, stout, scaly
Stems: loosely tufted, 1.5 – 4.5 mm wide, erect, internodes hairless, nodes somewhat hairy
Leaves: blades 10 – 70 cm long, 1 – 4 mm wide, usually hairless; sheaths round, distinctly veined, dull green to bluish, hairless or sparsely stiff hairy; ligules 2 – 6 mm long; ear-like lobes thick, pointed
Inflorescence: 20 – 70 cm, loosely contracted, yellowish to brownish
Spikelets: 5 – 9 mm long, fertile florets 1
Florets: glumes 5 – 8 mm long, lower hairy and 7 – 9-veined, upper hairless and 5-veined; thickened hardening blunt, long-hairy; lemmas dry and membranous; lemma awns 10 – 22 mm long, bent, twisted at the base; stamens 3, ovary hairless
Fruits: grain 2 – 3 mm long
 
POACEAE KEY FOR GENERA FOUND IN SASKATCHEWAN
 
1 Spikelets with one fertile floret, may have one sterile or male floret below the fertile floret; spikelets dorsally compressed; separation below the glumes
2
1 Spikelets with one or more fertile florets; sterile florets if present above the fertile florets; spikelets laterally compressed; separation usually above the glumes (except Beckmannia, Leersia, Spartina, and Sphenopholis) OR with two sterile or male florets below the single perfect floret
10
   
2 Spikelets in pairs; glumes leathery; palea membranous
3
2 Spikelets not in pairs; glumes membranous; palea hardened
5
   
3 Each stem terminating in a single spike
Schizachyrium
3 Each stem terminating in panicles with 2 to many branches
4
 
4 Tufted perennials; inflorescences terminal and axillary, composed of finger-like clusters; inflorescences subtended by a modified leaf; central axis and flower stalks white or yellow hairy
Andropogon
4 Rhizomatous perennials; inflorescences terminal, composed of elongate central axes and branched branches; central axis and flower stalks yellow-brown hairy
Sorghastrum
 
5 Spikelets subtended by a whorl of one to many rough bristles (inserted below the ovary)
Setaria
5 Spikelets without a whorl of rough bristles
6
 
6 Glumes or lower (sterile) lemmas awned
Echinochloa
6 Glumes and lemmas without awns
7
 
7 Inflorescence a slender, spike-like raceme; upper lemmas and paleas cartilaginous; ligule membranous
Digitaria
7 Inflorescence an open, branched cluster; upper lemmas and paleas dry and membranous to hardened; ligule, when present, a ring of hairs
8
   
8 At least some leaves without ligules
Echinochloa
8 All leaves with ligules
9
 
9 Basal leaves (winter rosette) different from stem leaves; spikelets obtuse to acute; second glume and sterile lemma long-hairy
Dichanthelium
9 Basal and stem leaves similar; spikelets tapered to a long or short point; second glume and sterile lemma slightly rough-hairy
Panicum
 
10 Spikelets with one floret; lemmas terminating in a 3-branched awn
Aristida
10 Spikelets with one or more florets; lemmas not terminating in a 3-branched awn
11
 
11 Spikelets with 2 male or sterile florets below the single perfect floret
12
11 Spikelets not as above
13
 
12 Spikelets with 2 male florets below the single perfect floret; florets brown; plant sweet smelling
Hierochloë
12 Spikelets with 2 sterile florets below the single perfect floret; florets pale or green; plants not sweet smelling
Phalaris
 
13 Spikelets unisexual, inflorescence with spikelets of two kinds borne in distinct regions; large aquatic annuals
Zizania
13 Spikelets unisexual or bisexual, spikelets all appearing similar; annual or perennial, mostly terrestrial
14
 
14 Spikelets sessile or nearly so in a spike, usually 2-ranked (spikes may be arranged in branched clusters)
15
14 Spikelets distinctly stalked, in branched or unbranched clusters
36
 
15 Spikelets on one side of the central axis; spikes solitary or in heads, spikes, or panicles
16
15 Spikelets in rows on opposite sides of the central axis; spikes solitary and elongate
21
   
16 Spikelets unisexual (the two sexes on the same or on separate plants); female spikelets in bur-like clusters
Buchloë
16 Spikelets bisexual; spikes not in bur-like clusters
17
 
17 Plants with runners and hairy stems; leaves in bundles; inflorescence head-like and hidden among the leaves
Munroa
17 Plants not both with runners and hairy stems, but may be with one or the other; leaves not in bundles; inflorescence not head-like and hidden among the leaves
18
 
18 Spikes comb-like, solitary or in unbranched clusters; spikelets more than 4 mm long
19
18 Spikes not comb-like, in simple clusters; spikelets less than 4 mm long
20
 
19 Stems 20 – 40 cm tall; leaves 1 – 7 mm wide; spikes 1 – 2; fertile lemma 3-cleft at apex, teeth short awned or at least sharp-pointed; plants of dry ground
Bouteloua
19 Stems 30 – 150 cm tall; leaves 2 – 15 mm wide; spikes more than 3; fertile lemma entire or with two rounded teeth; plants of moist or saline soil
Spartina
 
20 Leaves flat, 5 – 10 mm wide; inflorescence narrow; spikelets nearly round, about 3 mm long; glumes unequal, narrow; plants of wet ground
Beckmannia
20 Leaves twisted, 1 – 2 mm wide; inflorescence open; spikelets lance-shaped, about 4 mm long; glumes equal, broad; plants of dry ground
Schedonnardus
 
21 Spikelets solitary at each node of the central axis
22
21 Spikelets 2 or more at each node of the central axis
29
 
22 Spikelets oriented with the edge towards the central axis; usually with only one glume
Lolium
22 Spikelets oriented with the broad side towards the central axis; 2 glumes usually present
23
 
23 Plants annual, cultivated (usually found near the cultivated fields); lemmas eccentrically keeled, nerves converging to form an awn, or not converging at apex
24
23 Plants perennial or weedy annuals; lemmas rounded or obscurely keeled, nerves converging toward apex
25
   
24 Glumes broad, 3-nerved; lemma nerves not converging at apex
Triticum
24 Glumes linear-narrowly triangular, 1-nerved; lemma nerves converging to form an awn
Secale
 
25 Spikes strongly flattened and comb-like; spikelets divergent; leaves relatively short and rigid; tufted annuals
Agropyron
25 Spikes not flattened and comb-like, round or nearly so; spikelets ascending; leaves longer, not rigid; perennials
26
 
26 Glumes and lemmas blunt at apex, occasionally with a sharp point; stems solid
Thinopyrum
26 Glumes and lemmas acute to awned at apex; stems hollow
27
 
27 Rhizome short or absent; spike open; spikelets distant, generally shorter than internodes; glumes 4 – 6-nerved; lemma awns 1 – 2 cm long, divergent
Pseudoroegneria
27 Plants not as above
28
 
28 Glumes rigid; ear-like lobes at base of leaf often purplish; plants bluish green
Pascopyrum
28 Glumes not rigid; ear-like lobes at base of leaf yellowish-green; plants green or gray-green
Elymus
 
29 Spikelets in threes at each node of central axis, 1-flowered, the lateral pair of spikelets usually reduced to awns
Hordeum
29 Spikelets in pairs at least at some nodes of central axis, 2 – 6-flowered, spikelets all similar
30
 
30 Spikelets paired at lower nodes, solitary at middle and upper nodes
X Elyhordeum
30 Spikelets paired at all nodes
31
 
31 Rhizomes long, creeping and stout; spikelets mostly hairy
32
31 Rhizomes short or absent; spikelets hairy or hairless
35
   
32 Glumes lance-shaped
Leymus
32 Glumes narrowly triangular
33
 
33 Glumes purplish; lemmas densely hairy with long, silky hairs
Leymus
33 Glumes greenish; lemmas hairless or otherwise hairy
34
 
34 Lemmas awnless
Leymus
34 Lemmas awned
Elyleymus
 
35 Glumes narrowly triangular, not broadened above the base, not awned; lemmas awnless or with a short awn
Psathrostachys
35 Glumes narrowly lance-shaped, somewhat broadened above the base, commonly awned; lemmas frequently long-awned (0.5 – 4 cm)
Elymus
 
36 Spikelets very flat and 1-flowered; glumes absent or small; stamens 6
Leersia
36 Spikelets more or less compressed but not flattened, one or more flowered; one or two glumes present; stamens 3
37
 
37 Spikelets with one perfect floret
38
37 Spikelets with two or more perfect florets
55
 
38 Lemma hardened, enclosing palea and caryopsis
39
38 Lemma thin, commonly membranous, not enclosing palea and caryopsis
45
 
39 Lemma awnless
Milium
39 Lemma awned
40
 
40 Florets plump; lemma awn weak and deciduous
41
40 Florets slender; lemma awn firm and persistent
43
 
41 Inflorescence diffusely branched; glumes sharp-pointed; lemma long, silky hairy
Achnatherum
41 Inflorescence not diffusely branched; glumes blunt to soft-pointed; lemma hairless to short hairy
42
 
42 Leaves flat, to over 1 cm broad; spikelets 6 – 8 mm long, not including the awn; glumes distinctly 7-nerved
Oryzopsis
42 Leaves rolled, to 2 mm broad; spikelets 3 - 5 mm long, not including awn; glumes obscurely 5-nerved
Piptatherum
   
43 Glumes at least 1.5 cm long; lemma 8 – 20 mm long, awn 10 – 20 cm long
Hesperostipa
43 Glumes 1.5 cm long or less; lemma 4 – 6 mm long, lemma awn less than 6 cm long
44
 
44 Inflorescences open, branches spreading or drooping (if narrow and ascending, then lower nodes of inflorescence hairless and hardened thickening below lemma sharp-pointed)
Achnatherum
44 Inflorescence narrow, branches ascending to erect, lower nodes of inflorescence always long hairy and hardened thickening below lemma short and broad
Nasella
 
45 Florets stalked; stamens 1
Cinna
45 Florets not stalked; stamens usually 3
46
 
46 Lemmas awned
47
46 Lemmas awnless
51
   
47 Separation below the glumes; inflorescence dense and spike-like
48
47 Separation above the glumes, glumes persisting on mature inflorescence; inflorescences various
49
 
48 Glumes long-awned
Polypogon
48 Glumes awnless
Alopecurus
 
49 Hardened thickening below lemma bearing a tuft of long, straight hairs; lemma awned from the back below the middle
Calamagrostis
49 Hardened thickening below lemma hairless; lemma awned from tip or near tip
50
 
50 Delicate annuals; lemma awned on back, but above the middle
Agrostis
50 Perennials; lemma awned from tip
Muhlenbergia
 
51 Inflorescence cylindrical, dense, spike-like; glumes prominently boat-shaped or folded
Phleum
51 Inflorescence condensed to open but not cylindrical; glumes not conspicuously boat-shaped or folded
52
 
52 Hardened thickening below lemma with a prominent tuft of hairs; lemma 1-nerved
Calamovilfa
52 Hardened thickening below lemma without a prominent tuft of hairs; lemma 3 – 5-nerved
53
 
53 Ligule a fringe of hairs; grain plump, nearly round
Sporobolus
53 Ligule membranous; grain not plump and not round
54
 
54 Inflorescences open; glumes surpassing the lemmas
Agrostis
54 Inflorescences narrow and/or glumes shorter than lemmas
Muhlenbergia
 
55 Glume shorter than first floret; spikelets with 2 – many perfect florets; lemmas, if awned, awned from the tip or two-toothed apex
56
55 Glume as long as first floret or longer; spikelets generally with 3 or fewer perfect florets; lemmas if awned, awned from the back
71
   
56 Inflorescence feathery, central axis with long silky hairs; tall reeds
Phragmites
56 Inflorescence not feathery, central axis hairless or otherwise hairy; not tall reeds
57
 
57 Spikelets subsessile in one-sided clusters, strongly compressed
Dactylis
57 Spikelets stalked or sessile but not in one sided clusters or strongly compressed
58
 
58 Lemmas 3-nerved, awnless; ligule of hairs or fringed
59
58 Lemmas 5 – 11-nerved, may be awned; ligules membranous
61
 
59 Glumes and lemmas rounded on back; spikelets with 2 fertile florets
Catabrosa
59 Glumes and lemmas boat-shaped; spikelets with more than 2 fertile florets
60
 
60 Spikelets with 3 to many florets; glumes and lemmas thin and membranous
Eragrostis
60 Spikelets with up to 5 florets; glumes and lemmas green
Poa
 
61 Inflorescence with a few solitary branches; glumes papery; lemmas dissimilar, spikelet terminating in a club-shaped rudiment
Melica
61 Inflorescence usually compound; glumes not papery; lemmas similar, spikelet reduced at top but not modified into club-shaped rudiment
62
 
62 Lemmas boat-shaped, awnless
63
62 Lemmas rounded (if keeled, only near tip), may be awned
34
   
63 Plants dioecious; lemmas 9 – 11-nerved, rigid, and leathery; leaves rolled to flat, stiff; habitats usually saline
Distichlis
63 Plants with bisexual florets; lemmas 5-nerved, green or membranous; leaves softer, commonly boat-shaped at tip; habitats various
Poa
 
64 Lemmas distinctly 2-lobed at apex, often awned from apical notch
65
64 Lemmas entire or toothed, awn terminal
66
 
65 Hardened thickening at base of lemma bearded; ligule sheathing the stem and continuous with front sheath
Schizachne
65 Hardened thickening at base of lemma not bearded; ligule not sheathing the stem
Bromus
 
66 Hardened thickening at base of florets bearded; lemmas toothed at apex
Scolochloa
66 Hardened thickening at base of florets not bearded; lemmas entire
67
 
67 Lemma nerves arced, converging to midrib; lemmas awned
68
67 Lemma nerves parallel, not converging; lemmas not awned
69
 
68 Anthers 1; stems < 50 cm tall, annual
Vulpia
68 Anthers 3; stems frequently taller than 50 cm, perennial
Festuca
 
69 Lemma nerves 5, faint; plants of saline habitats
Puccinellia
69 Lemma nerves 7, conspicuous; plants of moist habitats
70
 
70 Leaf sheaths open; second glumes 3-nerved
Torreyochloa
70 Leaf sheaths at least partially united; glumes 1-nerved
Glyceria
   
71 Lemma awnless or with a very short awn
72
71 Lemma distinctly awned
74
 
72 Inflorescence spike-like; glumes unequal in length but similar in shape; separation above the glumes
Koeleria
72 Inflorescence dense to open but not spike-like; glumes similar or dissimilar; separation below the glumes
73
 
73 Glumes dissimilar, the first linear, the second wider; leaves to 5 mm broad
Sphenopholis
73 Glumes similar in shape but unequal in length; leaves to 1 cm broad
Trisetum
 
74 Awn flattened, twisted, inserted in the notch between apical teeth; ligule a tuft of hairs
Danthonia
74 Awn not flattened, awn inserted dorsally; ligule membranous
75
 
75 Lemmas 4-nerved, apex nearly square, 2 – 4-toothed; spikelets less than 1 cm long
Deschampsia
75 Lemmas 5 – 9-nerved, apex tapering, 2-toothed; spikelets greater than 1 cm long
76
 
76 Glumes 2 – 3.5 cm long, usually 7-nerved
Avena
76 Glumes less than 1.5 cm long, usually 5-nerved
Avenula