familyPoaceae
subfamilyPoaceae subfam. Pooideae
tribePoaceae tribe Poeae
genusAvenula
speciesAvenula hookeri

Avenula hookeri

(Scribn.) Holub
Gordon C. Tucker
Common names: Spike oatgrass
Synonyms: Helictotrichon hookeri
Treatment appears in FNA Volume 24. Treatment on page 698.
Please click on the illustration for a higher resolution version.
Illustrator: Linda Ann Vorobik, Hana Pazdírková

Copyright: Utah State University

Plants cespitose, not stoloniferous. Culms 10-75 cm, erect. Sheaths closed for less than 1/3 their length, smooth to scabridulous; ligules 3-7 mm, acute, usually lacerate; blades usually 4-20 cm long, 1-4.5 mm wide, smooth to scabridulous, margins cartilaginous and whitish. Panicles (4) 6-11 (13) cm long, usually 0.8-2.5 cm wide, erect or ascending; branches 10-25 mm, usually straight, stiff, usually with 1-2 spikelets. Spikelets 12-16 mm, with 3-6 florets; rachilla internodes usually 1.5-2.5 mm, hairs 0.2-1.5 mm. Glumes thin, acute; lower glumes 9-13 mm, 3-veined; upper glumes 9-14 mm, 3-5-veined; calluses bearded, hairs usually shorter than 1 mm; lemmas 10-12 mm, awned, awns 10-17 mm, flattened below the bend; paleas 6-8.75 mm; anthers 2.5-5 mm. 2n = 14.

Distribution

Colo., N.Mex., Minn., N.Dak., Alta., B.C., Man., N.W.T., Que., Sask., Yukon, Mont., Vt., Wyo., S.Dak.

Discussion

Avenula hookeri grows on mesic to dry, open prairie slopes, hillsides, forest openings, and meadows, in montane to subalpine zones, from the Yukon and Northwest Territories to northern New Mexico.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number.

... more about "Avenula hookeri"
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2n chromosome quantity
14 +
Abaxial ligule presence
absent +
Abaxial ligule quantity
common +
Adaxial cell presence
absent +
Adaxial cell shape
bulliform +
Adaxial ligule architecture or pubescence or shape
ciliate +
Adaxial ligule presence
absent +
Adaxial ligule texture
membranous +  and scarious +
Adaxial surface architecture
unribbed +
Anther quantity
3 +
Anther some measurement
0.25 cm2.5 mm <br />0.0025 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Apex architecture or shape
bifid +
Arm cell presence
absent +
Auricle presence
absent +
Author
Gordon C. Tucker +
Authority
(Scribn.) Holub +
Awn architecture
twisted +
Awn atypical quantity
1 (?) +  and 3 (?) +
Awn course
straight +
Awn orientation
arising +
Awn position
basal +  and terminal +
Awn quantity
single +
Awn shape
flattened +
Awn some measurement
1 cm10 mm <br />0.01 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
Back shape
keeled +  and rounded +
Basal floret quantity
1 +  and 2 +
Base architecture
pseudopetiolate +  and branching +
Base arrangement
close +
Base fusion
free +
Base position
intravaginal +, extravaginal +, branching +  and basal +
Base size
swelling +
Base texture
hard +
Base width
thick +
Blade arrangement
parallel +
Blade arrangement or course or shape
linear +
Blade length
4 cm40 mm <br />0.04 m <br /> (20 cm200 mm <br />0.2 m <br />) +
Blade prominence
not evident +
Blade relief
smooth +  and scabridulous +
Blade shape
folded +  and flat +
Blade width
0.1 cm1 mm <br />0.001 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
Branch course
straight +
Branch fragility
stiff +
Branch quantity
many +
Branch shape
spikelike +
Branch some measurement
1 cm10 mm <br />0.01 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
Callus development
developed +
Callus pubescence
bearded +
Callus shape
acute +
Common name
Spike oatgrass +
Culm architecture
not branching +
Culm architecture or arrangement or growth form
solitary +
Culm duration
annual +
Culm growth form
climbing +
Culm growth form or location
floating +
Culm orientation
erect +
Culm some measurement
10 cm100 mm <br />0.1 m <br /> (75 cm750 mm <br />0.75 m <br />) +
Culm texture
not woody +
Distal floret size
reduced +
Distribution
Colo. +, N.Mex. +, Minn. +, N.Dak. +, Alta. +, B.C. +, Man. +, N.W.T. +, Que. +, Sask. +, Yukon +, Mont. +, Vt. +, Wyo. +  and S.Dak. +
Embryo quantity
1/4 +  and 1/3 +
Endosperm texture
semiliquid +  and liquid +
Filament shape
capillary +
Floret architecture
pistillate +  and staminate +
Floret arrangement
adjacent +
Floret length or size
sometimes longer +
Floret position or shape
distal +
Floret quantity
3 +  and 6 +
Floret reproduction
sterile +  and bisexual +
Floret shape
compressed +
Floret size
reduced +
Glume architecture
1-3-veined +
Glume architecture or shape
awned +
Glume height or length or size
shorter +
Glume length or size
shorter or longer +
Glume position
subtending +
Glume presence
absent +
Glume quantity
2 +
Glume shape
acute +
Glume size
unequal +
Glume variability
equal +
Glume width
thin +
Hair shape
uncinate +
Hair some measurement
1 cm10 mm <br />0.01 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
Hilum arrangement or course or shape
linear +
Hilum coloration or relief
punctate +
Hilum shape
Ovate (?) +
Illustration
Present +
Illustration copyright
Utah State University +
Illustrator
Linda Ann Vorobik +  and Hana Pazdírková +
Inflorescence architecture
compound +
Inflorescence position or structure subtype
terminal +
Internode architecture
hollow +
Internode presence
absent +
Layer presence
absent +
Leaf arrangement
distichous +
Leaf margin arrangement
Overlapping (?) +
Lemma architecture
5-7-veined +
Lemma architecture or shape
awned +
Lemma arrangement
adjacent +
Lemma height or length or size
shorter +
Lemma length or size
longer +
Lemma shape
obtuse +
Lemma some measurement
1 cm10 mm <br />0.01 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
Ligule presence
absent +
Ligule shape
lacerate +  and acute +
Ligule some measurement
0.3 cm3 mm <br />0.003 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
Ligule texture
membranous +
Lodicule architecture
veined +
Lodicule architecture or pubescence or shape
ciliate +
Lodicule architecture or shape
entire +
Lodicule prominence
inconspicuous +
Lodicule quantity
2 +
Lodicule shape
unlobed +
Lodicule texture
membranous +
Lower glume architecture
3-veined +
Lower glume some measurement
0.9 cm9 mm <br />0.009 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
Margin architecture
sclerenchymatous +
Margin coloration
whitish +
Margin pubescence or texture
cartilaginous +
Midrib architecture
simple +
Node prominence
concealed +  and prominent +
Number of lower taxa
0 +
Other quantity
2 +  and 1 +
Ovary presence
absent +
Ovary pubescence
hairy +  and glabrous +
Palea development
well-developed +
Palea presence
absent +
Palea shape
2-keeled +
Palea size
minute +
Palea some measurement
0.6 cm6 mm <br />0.006 m <br /> (0.875 cm8.75 mm <br />0.00875 m <br />) +
Panicle length
6cm +  and 11cm +
Panicle orientation
ascending +  and erect +
Panicle shape
spikelike +
Panicle size
reduced +
Panicle width
0.8 cm8 mm <br />0.008 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
Papilla presence
absent +
Pericarp arrangement
separating +
Pericarp condition or texture
dry +
Pericarp texture
dry +  and fleshy +
Pericarp width
thin +
Pseudopetiole development
not developed +
Pseudopetiole presence
absent +
Rachilla length
prolonged +
Rachilla pubescence
hairy +  and glabrous +
Rachis prominence
evident +
Reference
None +
Sheath architecture
open +
Sheath condition
closed +
Sheath length
closed +
Sheath relief
smooth +  and scabridulous +
Side arrangement
adjacent +
Source xml
https://bibilujan@bitbucket.org/aafc-mbb/fna-fine-grained-xml.git/src/84153f6d59a0a91d69695978a64cee7560374f8e/V24/V24 988.xml +
Spike architecture
ebracteate +
Spikelet arrangement
mixed +
Spikelet fixation
attached +
Spikelet quantity
1 +  and 2 +
Spikelet reproduction
viviparous +
Spikelet shape
compressed +
Spikelet some measurement
1.2 cm12 mm <br />0.012 m <br /> (1.6 cm16 mm <br />0.016 m <br />) +
Stamen quantity
1 +  and 3 +
Starch-grain architecture
simple +  and compound +
Style-branch atypical quantity
4 +  and 1 +
Style-branch quantity
2 (?) +  and 3 (?) +
Style quantity
2 +
Subsidiary-cell architecture
parallel-sided +
Synonyms
Helictotrichon hookeri +
Taxon family
Poaceae +
Taxon name
Avenula hookeri +
Taxon parent
Avenula +
Taxon rank
species +
Terminal floret reproduction
sexual +
Tissue coloration
hyaline +
Tissue texture
membranous +
Upper glume architecture
3-5-veined +
Upper glume some measurement
0.9 cm9 mm <br />0.009 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
Vein arrangement
parallel +  and converging +
Vein presence
absent +
Vein quantity
2 (?) +
Vein size
major +
Volume
Volume 24 +
Whole organism architecture
not stoloniferous +
Whole organism arrangement or pubescence
tufted +
Whole organism duration
perennial +
Whole organism growth form
plant +  and cespitose +
Whole organism growth form or habitat
aquatic +  and terrestrial +
X chromosome quantity
7 +