Achnatherum coronatum

(Thurb.) Barkworth
Common names: Crested needlegrass
Synonyms: Stipa coronata
Treatment appears in FNA Volume 24. Treatment on page 127.
Please click on the illustration for a higher resolution version.
Illustrator: Cindy Roché

Copyright: Utah State University

Plants loosely cespitose, shortly rhizomatous, bases knotty. Culms 55-210 cm tall, 3-6 mm thick, internodes usually glabrous, lower internodes sometimes puberulent; nodes 1-2, glabrous. Basal sheaths mostly glabrous, often puberulent on the lower portion, flat, ribbon¬like with age, margins hairy distally, hairs 1-2.5 mm; collars mostly glabrous; ligules 0.4-1.6 (3) mm, truncate to slightly rounded, abaxial surfaces pubescent, ciliate, cilia about 0.5 mm; blades usually flat, 2.5-7 mm wide, both surfaces scabrous. Panicles 15-60 cm long, 2-4 cm wide; branches widely spreading to ascending, longest branches 4-13 cm. Glumes lanceolate, glabrous, tapering to awnlike apices; lower glumes 16-21 mm long, 1-1.3 mm wide, midveins scabrous; upper glumes 11-18 mm; florets 6.5-10 mm long, about 1 mm thick, fusiform, terete; calluses 0.5-2 mm, blunt to acute; lemmas densely hairy, hairs at midlength 1.5-4 mm, apical hairs 2-5 mm; awns 25-45 mm, persistent, twice-geniculate, all segments scabrous, terminal segment straight; paleas 3.5-5.5 mm, 3/5 – 9/10 as long as the lemmas, sparsely hairy between the veins, apices flat, rounded; anthers 3-4 mm, dehiscent, not penicillate. Caryopses 5-7 mm, fusiform. 2n = 40.

Discussion

Achnatherum coronatum grows on gravel and on rocky slopes, mostly in chaparral associations of the Coast Range from Monterey County, California, to Baja California, Mexico. It is similar in size to A. diegoense, but differs in its mostly glabrous internodes and longer paleas. It differs from A. parishii, an inland species, in its twice-geniculate awns, more robust habit, and more sparsely pubescent paleas. Occasional plants combine the characteristics of both species.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number."prolonged" is not a number.

... more about "Achnatherum coronatum"
membranous +  and scarious +
not penicillate +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
awned +, bifid +, bilobed +  and entire +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Mary E. Barkworth +
(Thurb.) Barkworth +
1 (?) +  and 3 (?) +
flexuous +
subterminal +  and eccentric +
usually scabrous +  and scabridulous +
not once-geniculate +
2.5 cm25 mm <br />0.025 m <br /> (4.5 cm45 mm <br />0.045 m <br />) +
keeled +  and rounded +
puberulent +  and glabrous +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
not evident +
involute +, convolute +  and flat +
2.5mm;7mm +
flexuous +  and straight +
widely spreading;ascending +
spikelike +
well-developed +
blunt +  and acute +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (?) +
Crested needlegrass +
branching +  and not branching +
perennial +  and annual +
55 cm550 mm <br />0.55 m <br /> (210 cm2,100 mm <br />2.1 m <br />) +
intravaginal +  and basal +
10 cm100 mm <br />0.1 m <br /> (250 cm2,500 mm <br />2.5 m <br />) +
not woody +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
1/5 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
0.65 cm6.5 mm <br />0.0065 m <br /> (1 cm10 mm <br />0.01 m <br />) +
sometimes longer +
terete +  and fusiform +
1-10-veined +
subtending +
tapering +  and awnlike +
membranous +
divergent +  and distributed +
uncinate +
0.1 cm1 mm <br />0.001 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
solid +  and hollow +
basally concentrated +  and evenly distributed +
0 cm0 mm <br />0 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
ovate +, rectangular +  and lanceolate +
stiffly membranous +  and coriaceous +
pubescent +  and glabrous +
truncate +  and slightly rounded +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.16 cm1.6 mm <br />0.0016 m <br />) +
membranous +
membranous +
inconspicuous +
not lobed +
4 cm40 mm <br />0.04 m <br /> (13 cm130 mm <br />0.13 m <br />) +
1.6 cm16 mm <br />0.016 m <br /> (2.1 cm21 mm <br />0.021 m <br />) +
1mm +  and 1.3mm +
concealed +  and prominent +
1 +  and 2 +
2 +  and 1 +
pubescent +  and glabrous +
well-developed +
3/5 +  and 9/10 +
not keeled +
reduced +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.55 cm5.5 mm <br />0.0055 m <br />) +
15cm +  and 60cm +
2 cm20 mm <br />0.02 m <br /> (4 cm40 mm <br />0.04 m <br />) +
dry +  and fleshy +
not prolonged +
1 +  and 60 +
unisexual +  and bisexual +
laterally compressed +  and terete +
1 (?) +  and 3 (?) +
simple +  and compound +
Stipa coronata +
Achnatherum coronatum +
Achnatherum +
species +
membranous +
1.1 cm11 mm <br />0.011 m <br /> (1.8 cm18 mm <br />0.018 m <br />) +
inconspicuous +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
plant +  and cespitose +
aquatic +  and terrestrial +