Agrostis hendersonii

Hitchc.
Common names: Henderson's bent
Endemic
Synonyms: Agrostis aristiglumis
Treatment appears in FNA Volume 24. Treatment on page 658.
Please click on the illustration for a higher resolution version.
Illustrator: Sandy Long

Copyright: Utah State University

Plants annual. Culms 6-70 cm, erect, with 2-5 nodes. Sheaths smooth; ligules 0.5-5 mm, usually scabridulous, dorsal surfaces sometimes smooth, apices acute to obtuse, erose-lacerate, sometimes ciliolate; blades 1-4.5 cm long, 0.5-1 (2) mm wide, flat or weakly involute. Panicles 1-5 cm long, 0.5-1.5 cm wide, cylindrical, spikelike, dense, sometimes interrupted near the base, usually well exserted from the upper sheaths; branches scabridulous, ascending to appressed, mostly hidden by the spikelets, lower branches 0.5-2.5 cm; pedicels 0.5-4 (6.3) mm. Spikelets lanceolate, greenish to yellowish, tinged with purple. Glumes subequal, 5-7 mm, scabrous over the midvein, often sparsely scabridulous over the body, 1 (3) -veined, apices narrowly acuminate to awn-tipped to 2 mm; callus hairs to 0.7 mm, abundant; lemmas 2.5-4 mm, scabridulous over the veins and sometimes over the body, opaque to translucent, 5-veined, veins prominent distally, apices acute, veins extended into 2 teeth, teeth 0.2-1.5 mm, awned from about midlength, awns (5) 8-10 mm, more or less geniculate; paleas absent or to 0.9 mm; anthers 3, 0.4-0.7 mm. Caryopses 1.6-1.8 mm. 2n = 42.

Discussion

Agrostis hendersonii is a rare species that grows below 600 m in clay or adobe, sometimes rocky, soils around the edges of vernal pools in Oregon and California.

Agrostis aristiglumis Swallen, known only from its type locality on the Point Reyes Peninsula, Marin County, California, is included here in A. hendersonii. It differs from A. hendersonii in having a palea up to 0.9 mm long, and a barely exserted panicle. The relationship of these to each other and to A. microphylla merits investigation. Their differences may be the result of the founder effect on inbreeding annuals.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number.

... more about "Agrostis hendersonii"
membranous +  and scarious +
not penicillate +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.07 cm0.7 mm <br />7.0e-4 m <br />) +
awned +, truncate +  and entire +
Acute (?) +, Acuminate (?) +, Erose-lacerate (?) +  and Obtuse (?) +
0 cm0 mm <br />0 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
M.J. Harvey +
Hitchc. +
1 (?) +  and 3 (?) +
5 cm50 mm <br />0.05 m <br /> (?) +
straight +
basal +  and terminal +
geniculate +
0.8 cm8 mm <br />0.008 m <br /> (1 cm10 mm <br />0.01 m <br />) +
rounded +  and keeled +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
1 cm10 mm <br />0.01 m <br /> (4.5 cm45 mm <br />0.045 m <br />) +
not evident +
scabridulous +
involute +  and flat +
0.5mm;1mm +
ascending;appressed +
scabridulous +
spikelike +
0 cm0 mm <br />0 m <br /> (0.07 cm0.7 mm <br />7.0e-4 m <br />) +
hairy +  and glabrous +
Henderson's bent +
not branching +
6 cm60 mm <br />0.06 m <br /> (70 cm700 mm <br />0.7 m <br />) +
not woody +
Calif. +  and Oreg. +
1/4 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sometimes longer +
sterile +  and bisexual +
compressed +
reduced +
(1)1.3-2(4) times longer than +
subtending +
scabridulous +
subequal +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
uncinate +
diffuse +  and dense +
opaque +  and translucent +
pubescent +  and glabrous +
scabridulous +
lanceolate +  and ovate +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
membranous +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
membranous +
inconspicuous +
lanceolate +
0.5 cm5 mm <br />0.005 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
concealed +  and prominent +
2 +  and 5 +
2 +  and 1 +
well-developed +
2-keeled +
minute +  and subequal +
1cm +  and 5cm +
spikelike +  and cylindrical +
0.5 cm5 mm <br />0.005 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
6.3 cm63 mm <br />0.063 m <br /> (?) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
dry +  and fleshy +
not prolonged +
hairy +  and glabrous +
scabrous +  and scabridulous +
tinged with purple +, greenish +  and yellowish +
1 +  and 60 +
lanceolate +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
1 (?) +  and 3 (?) +
simple +  and compound +
2 (?) +  and 3 (?) +
Agrostis aristiglumis +
Agrostis hendersonii +
Agrostis +
species +
membranous +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
not convergent +
scabrous +  and scabridulous +
extended +
stoloniferous +  and rhizomatous +
aquatic +  and terrestrial +