Apera interrupta

(L.) P. Beauv.
Common names: Interrupted windgrass
Introduced
Synonyms: Agrostis interrupta
Treatment appears in FNA Volume 24. Treatment on page 789.

Culms (5) 10-50 (75) cm, weak, slender, solitary or with several shoots, sometimes sparingly branched above the base; internodes usually longer than the sheaths. Sheaths often purplish; ligules 1.5-5 mm, acute to truncate, erose, margins decurrent; blades usually 4-12 cm long, 0.3-4 mm wide, flat or convolute when dry. Panicles 3-15 (20) cm long, 0.4-1.5 (3) cm wide, contracted, somewhat interrupted below; branches erect to ascending, most spikelet-bearing to within 2 mm of the base; pedicels 0.5-2 mm. Spikelets 2-2.8 mm, green or purplish; rachillas prolonged 0.2-0.6 mm. Lower glumes 1-2.2 mm; upper glumes 2-2.5 (2.8) mm; lemmas 1.5-2.5 mm, slightly involute, awned, awns 4-10 (16) mm; anthers 0.3-0.5 mm, often purplish brown. Caryopses 1-1.5 mm. 2n = 14, 28.

Distribution

Wash., Oreg., Wis., Wyo., N.J., N.Mex., Pacific Islands (Hawaii), Ohio, N.Y., B.C., Ont., Nev., Colo., Calif., Ill., Ind., Ariz., Idaho, Maine, Mont., Mass., Utah, Mo., Mich.

Discussion

Apera interrupta grows as a weed in lawns, grain fields (especially winter wheat), sandy open ground, and roadsides. Introduced from Europe, it now grows from British Columbia south to Arizona and New Mexico, as well as in Ontario and at a few scattered locations in the eastern part of the Flora region.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number.

... more about "Apera interrupta"
membranous +  and scarious +
purplish brown +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
awned +  and entire +
Kelly W. Allred +
(L.) P. Beauv. +
1 (?) +  and 3 (?) +
16 cm160 mm <br />0.16 m <br /> (?) +
straight +
subterminal +
0.4 cm4 mm <br />0.004 m <br /> (1 cm10 mm <br />0.01 m <br />) +
keeled +  and rounded +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
4 cm40 mm <br />0.04 m <br /> (12 cm120 mm <br />0.12 m <br />) +
not evident +
convolute +  and flat +
0.3mm;4mm +
spikelike +
hairy +  and glabrous +
Interrupted windgrass +
with several shoots +  and solitary +
geniculate +
slender +
10 cm100 mm <br />0.1 m <br /> (50 cm500 mm <br />0.5 m <br />) +
not woody +
Wash. +, Oreg. +, Wis. +, Wyo. +, N.J. +, N.Mex. +, Pacific Islands (Hawaii) +, Ohio +, N.Y. +, B.C. +, Ont. +, Nev. +, Colo. +, Calif. +, Ill. +, Ind. +, Ariz. +, Idaho +, Maine +, Mont. +, Mass. +, Utah +, Mo. +  and Mich. +
1/4 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sterile +  and bisexual +
compressed +
reduced +
shorter or longer +
subtending +
lanceolate +
unequal +
uncinate +
folded +  and nearly terete +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
acute to truncate +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
membranous +
inconspicuous +
0.1 cm1 mm <br />0.001 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
decurrent +
concealed +  and prominent +
2 +  and 1 +
well-developed +
2-keeled +
3cm +  and 15cm +
spikelike +
0.4 cm4 mm <br />0.004 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
dry +  and fleshy +
rounded +  and slightly keeled +
Introduced +
purplish +  and green +
1 +  and 60 +
compressed +
0.2 cm2 mm <br />0.002 m <br /> (0.28 cm2.8 mm <br />0.0028 m <br />) +
1 (?) +  and 3 (?) +
simple +  and compound +
2 (?) +  and 3 (?) +
Agrostis interrupta +
Apera interrupta +
species +
membranous +
slightly shorter than to slightly longer than the florets +
0.2 cm2 mm <br />0.002 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
parallel +  and converging +
stoloniferous +  and rhizomatous +
aquatic +  and terrestrial +