Juncus rugulosus Engelmann

Herbs, perennial, rhizomatous, 3--7.5 dm. Rhizomes 2--3 mm diam., not swollen. Culms erect, terete, 2--4 mm diam., smooth or rugulose. Cataphylls 1--2, pink to straw-colored, apex acute. Leaves: basal 1--2, cauline 1--2; auricles 1--4.9 mm, , apex rounded, membranaceous; blade green to straw-colored, terete, 20--30 cm x 1.5--4 mm, rugulose or smooth. Inflorescences terminal panicles of 25--66 heads, 7--13 cm, branches spreading; primary bract erect; heads 6--10-flowered, hemispheric to obovoid, 5--10 mm diam. Flowers: tepals straw-colored to brown, lanceolate, apex acuminate; outer tepals (2--)2.5--3.4 mm; inner tepals (2--)2.6--3.6 mm; stamens 6, anthers 1.5--2 times filament length. Capsules exserted, chestnut brown, 1-locular, subuloidsubulate, (2.4--)3--3.9 mm, apex tapering to subulate tip, valves separating at dehiscence. Seeds obovoid, 0.3--0.4 mm, not tailed. 2n = 40.

Fruiting early summer--late fall. Montane meadows, riverbeds, canyons, aroyos; 100--1600 m; Calif.

Juncus dubius has rugulose stems and leaves throughout most of its range, but on the periphery (in Mariposa, San Diego, and Sonoma counties, California) the plants are smooth.