Trisetum orthochaetum

Hitchc.
Common names: Bitterroot trisetum
Endemic
Treatment appears in FNA Volume 24. Treatment on page 746.
Please click on the illustration for a higher resolution version.
Illustrator: Cindy Roché

Copyright: Utah State University

Plants perennial, with both fertile and sterile shoots; shortly rhizomatous. Culms 80-110 cm, solitary, decumbent, often anthocyanic at the base, glabrous. Leaves evenly distributed; sheaths usually glabrous; ligules 3-5 mm, truncate or rounded, erose; blades 8-20 cm long, 3-7 mm wide, flat, lax, scabrous. Panicles 13-20 cm, narrow, moderately dense, nodding, pale green, slightly tinged with purple; branches loosely ascending, naked below for 1-2 cm, the spikelets closely and evenly distributed distally. Spikelets 7-9 mm, subsessile or on pedicels to 1 cm, oblong-ovate, with 2-3 (4) florets; rachilla internodes to 2 mm; rachilla hairs about 1 mm. Glumes lanceolate or oblanceolate; lower glumes about 5.5 mm long, about 1 mm wide, widest near the base, slenderly acuminate; upper glumes to 6.3 mm long, about 2 mm wide at or just above the middle, acuminate; callus hairs about 0.5 mm; lemmas 5-6.5 mm long, about 1/3 as wide as long, apices bifid, teeth shorter than 1 mm, awned, awns 4-6 mm, arising about 1 mm below the teeth, not twisted basally, straight or flexuous, exceeding the lemma apices; paleas almost equaling the lemmas; anthers minute or to 1 mm, appearing nonfunctional; ovaries pubescent. Caryopses to 2.5 mm, malformed. 2n = unknown.

Discussion

Trisetum orthochaetum is known only from Montana, in or near the edges of marshes, seeps, and creeksides, where it grows at about 1465 m. It may be a sterile hybrid between T. canescens and T. wolfii (Shelly 1987).

Selected References

None.

Lower Taxa

None.

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

... more about "Trisetum orthochaetum"
membranous +  and scarious +
0-1 mm +  and minute +
John H. Rumely +
Hitchc. +
1 (?) +  and 3 (?) +
flexuous +  and straight +
basal +  and terminal +
1 cm10 mm <br />0.01 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
keeled +  and rounded +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
8 cm80 mm <br />0.08 m <br /> (20 cm200 mm <br />0.2 m <br />) +
not evident +
3mm;7mm +
spikelike +
0.5 cm5 mm <br />0.005 m <br /> (?) +
Bitterroot trisetum +
anthocyanic +
ascending +  and erect +
extravaginal +  and basal +
80 cm800 mm <br />0.8 m <br /> (110 cm1,100 mm <br />1.1 m <br />) +
not woody +
0 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sometimes longer +
2 +  and 3 +
sterile +  and bisexual +
compressed +
reduced +
shorter or longer +
subtending +
oblanceolate +  and lanceolate +
unequal +  and subequal +
uncinate +
diffuse +  and dense +
distributed +
0.5 cm5 mm <br />0.005 m <br /> (0.65 cm6.5 mm <br />0.0065 m <br />) +
lanceolate +  and ovate +
rounded +  and truncate +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
membranous +
inconspicuous +
usually slenderly lobed +  and fimbriate +
5.5 cm55 mm <br />0.055 m <br /> (?) +
widest +  and 1 +
concealed +  and prominent +
2 +  and 1 +
well-developed +
2-keeled +
subequal +  and longer +
membranous +
tinged with purple +  and pale green +
spikelike +
13 cm130 mm <br />0.13 m <br /> (20 cm200 mm <br />0.2 m <br />) +
0 cm0 mm <br />0 m <br /> (1 cm10 mm <br />0.01 m <br />) +
dry +  and fleshy +
1 cm10 mm <br />0.01 m <br /> (?) +
sterile +  and fertile +
on pedicels +  and subsessile +
1 +  and 60 +
oblong-ovate +
0.7 cm7 mm <br />0.007 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
1 (?) +  and 3 (?) +
simple +  and compound +
2 (?) +  and 3 (?) +
Gramineae +
Trisetum orthochaetum +
Trisetum +
species +
bristlelike +
membranous +
1 cm10 mm <br />0.01 m <br /> (?) +
0 cm0 mm <br />0 m <br /> (0.63 cm6.3 mm <br />0.0063 m <br />) +
parallel +  and converging +
aquatic +  and terrestrial +