Common Name: Baltic rush
Duration: Perennial
Nativity: Native
Lifeform: Graminoid
General: Perennial rush, 20-100 cm tall, from long, stout, dark-colored rhizomes, 2-4 mm thick; stems arising singly and spaced up to 3cm apart, or occasionally a few clumped; stems wiry, round or slightly compressed in cross section, 1-6 mm diameter at the base.
Vegetative: Leaves present only as 3-6 bladeless sheaths (cataphylls) around each stem; sheaths straw-colored to rich brown, often shiny and longitudinally wrinkled, the upper sheath sometimes mucronate (abruptly pointed at the tip) or tipped with a delicate awn up to 3 mm long, usually broken off in herbarium specimens.
Inflorescence: Few to many-flowered panicles, 2-10 cm long, emerging laterally from a slit in the upper half of the stem; flowers borne singly on pedicels in the inflorescence, or several close together, with 2 bracteoles at the base of each flower, and often a third bract below these that is longer and narrower than the bracteoles; bracteoles 1-2 mm long, broadly ovate and membraneous, with an abruptly pointed tip. Flowers with 6 tepals (petal-like structures) 3-5 mm long, lanceolate, straw-colored with a green midvein, brown or hyaline margins, and a long-pointed tip. Capsules ovoid, 3-6 mm long and 1.5 mm wide, usually longer than the tepals, straw-colored to brown, smooth and shiny, with a broadly rounded or acute tip and short point (mucro) less than 1 mm long on top. Seeds greyish to dark amber, less than 1 mm long.
Ecology: Found in wet meadows, stream banks and lakeshores, marshy areas, ditches, and open wetlands, often in alkaline areas, tolerating soils that dry out seasonally; grows at middle to high elevations in the Southwest; flowers June-August.
Distribution: Throughout western N. Amer. from AK to the Rocky Mountains; south to MEX, C. and S. Amer; also in Europe, Asia.
Notes: This species is distinguished by being a rhizomatous perennial, with round or slightly compressed stems 2-4 mm thick at the base (J. mexicanus has compressed, twisted stems less than 2 mm thick); leaves represented only by sheaths around the stems with no true blades attached; the inflorescence emerging from the side of the stem several cm below the top; and each flower subtended by a pair of ovate, membranaous bracteoles (use your hand lens). There are 6 subspecies and 2 subspecies in North America. Arizona plants belong to subsp. ater. Look for this taxon under J. arcticus var. balticus or J. balticus var. montanus in older texts.
Ethnobotany: Unknown
Etymology: Juncus means to tie or bind in Latin, referring to uses for the stems; balticus refers to the Baltic Sea.
Editor: AHazelton 2017
