Juncus arcticus var. mexicanus

(Willdenow ex Roemer & Schultes) Balslev

Brittonia 35: 308. 1983.

Common names: Mexican rush
Basionym: Juncus mexicanus Willdenow Syst. Veg. 7(1): 178. 1829
Synonyms: Juncus balticus var. mexicanus (Willdenow ex Roemer & Schultes) Kuntze
Treatment appears in FNA Volume 22.

Herbs, 2–8 dm. Culms usually compressed. Leaves: blade distinct, somewhat flattened, to 20 cm or more. Flowers: tepals usually brown or blackish, 3.5–4.5 (–5.5) mm; filaments 0.2–0.4 mm, anthers 1.2–2.2 mm.


Habitat: Intermittent or permanent water courses, around springs, and in meadows in sandy or gravelly soils
Elevation: 500–3200 m

Distribution

V22 416-distribution-map.jpg

Ariz., Calif., Colo., N.Mex., Nev., Utah, Mexico, Central America, South America

Discussion

Juncus arcticus var. mexicanus is the common phase of the species in the extreme southwest United States and Mexico; northward the variety becomes sporadic in its occurrence. Rare individuals having leaves with blades are sometimes found in otherwise bladeless populations in more northern areas but it is doubtful that these oddities represent an equivalent variant.

Selected References

None.

Lower Taxa

None.
persistent +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
acutish +  and obtuse +
Ralph E. Brooks* +  and Steven E. Clemants* +
(Willdenow ex Roemer & Schultes) Balslev +
Juncus mexicanus +
distinct +
flattened +
0 cm0 mm <br />0 m <br /> (20 cm200 mm <br />0.2 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
oblate;narrowly ovoid +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
Mexican rush +
compressed +
Ariz. +, Calif. +, Colo. +, N.Mex. +, Nev. +, Utah +, Mexico +, Central America +  and South America +
500–3200 m +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
arranged +  and cluster +
headlike +
Intermittent or permanent water courses, around springs, and in meadows in sandy or gravelly soils +
loose +  and congested +
3 +  and 1 +
green;brown or purplish black +
persistent +
parietal +  and axile +
dark amber +
oblate;ellipsoid +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
green;brown or purplish black +
persistent +
Illustrated +
generally longer +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (?) +  and 0.15 cm1.5 mm <br />0.0015 m <br /> (?) +
Juncus balticus var. mexicanus +
Juncus arcticus var. mexicanus +
Juncus arcticus +
variety +
0.45 cm4.5 mm <br />0.0045 m <br /> (0.55 cm5.5 mm <br />0.0055 m <br />) +
blackish +  and brown +
lanceolate +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +