Hygroryza aristata

(Retz.) Nees
Common names: Asian watergrass Water stargrass
Treatment appears in FNA Volume 24. Treatment on page 46.
Please click on the illustration for a higher resolution version.
Illustrator: Sandy Long

Copyright: Utah State University

Culms 50-150 cm, floating, branched, flexuous; nodes rooting, roots feathery, whorled. Sheaths glabrous, open, inflated; ligules absent or 0.5-0.8 mm, hyaline, truncate; pseudopetioles shorter than 1 mm; blades 2-8 cm long, 5-20 mm wide, flat, bases rounded to cordate, apices blunt to rounded. Panicles 3-8 cm, pyramidal, with 4-9 branches; lower branches 2-4 cm, whorled, spreading or deflexed, glabrous; pedicels 0.2-2 mm, sometimes absent. Florets (6) 7-18 mm (including the stipelike callus), narrowly lanceolate; calluses (1) 2-10 mm, stipelike; lemmas 5-8 mm, chartaceous, keeled, veins and margins with hairs, glabrous or pubescent between the veins, awns 5-14 mm; paleas as long as the lemmas, chartaceous, glabrous, keels ciliate or scabrous; anthers 6, about 3.5 mm. Caryopses about 3.5 mm. 2n = 24.

Discussion

Hygroryza aristata is native to tropical Asia, where it has occasionally been used as forage for cattle (Bor 1960). It is sold for ponds and aquaria, where its long, feathery, adventitious roots have a decorative effect, but it has the potential to become a significant weed problem in the southern United States.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number.

... more about "Hygroryza aristata"
3.5 cm35 mm <br />0.035 m <br /> (?) +
blunt +  and rounded +
J.K. Wipff +
(Retz.) Nees +
1 (?) +  and 3 (?) +
scabridulous +
0.5 cm5 mm <br />0.005 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
keeled +  and rounded +
pseudopetiolate +  and branching +
divergent +  and parallel +
not fused +
intravaginal +, extravaginal +, branching +  and basal +
rounded +  and cordate +
swelling +
2 cm20 mm <br />0.02 m <br /> (8 cm80 mm <br />0.08 m <br />) +
not evident +
oblong +, ovatelanceolate +, ovate +  and elliptic +
0.5 cm5 mm <br />0.005 m <br /> (2 cm20 mm <br />0.02 m <br />) +
spikelike +
stipelike +
0.2 cm2 mm <br />0.002 m <br /> (1 cm10 mm <br />0.01 m <br />) +
Asian watergrass +  and Water stargrass +
flexuous +
20 cm200 mm <br />0.2 m <br /> (500 cm5,000 mm <br />5 m <br />) +
ascending +  and erect +
50 cm500 mm <br />0.5 m <br /> (150 cm1,500 mm <br />1.5 m <br />) +
0 +  and 1/3 +
capillary +
sometimes longer +
sterile +, fertile +, sexual +, unisexual +  and bisexual +
lanceolate +
7mm +  and 18mm +
cylindrical +, oblong +  and ovoid +
subtending +
reduced +
uncinate +
solid +  and hollow +
scabrous +  and ciliate +
aerenchymatous +
0.5 cm5 mm <br />0.005 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
coriaceous +  and membranous +
scarious +  and membranous +
annular +
inconspicuous +
fleshy +  and membranous +
deflexed +  and spreading +
2 cm20 mm <br />0.02 m <br /> (4 cm40 mm <br />0.04 m <br />) +
pubescent +  and glabrous +
complex +  and simple +
concealed +  and prominent +
2 +  and 1 +
well-developed +
acute-acuminate +  and 1-keeled +
pyramidal +
3 cm30 mm <br />0.03 m <br /> (8 cm80 mm <br />0.08 m <br />) +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
dry +  and fleshy +
1 cm10 mm <br />0.01 m <br /> (?) +
not prolonged +
inflated +
[9/10] +, /2 +  and 1 +
compressed +
1 +  and 3 +
simple +  and compound +
2 (?) +  and 3 (?) +
triangular +  and dome--shaped +
Gramineae +
Hygroryza aristata +
Hygroryza +
species +
membranous +
pubescent +  and glabrous +