5. Juncus brachycarpus Engelm.
Pl.
94 d, e; Map 362
Aerial stems 30–80 cm tall, closely spaced along tuberous rhizomes. Leaves with
the auricles at the top of the sheaths 0.5–3.0 mm long, papery, rounded, the
leaf blades 3–50 cm long, 1–2 mm wide, tubular and hollow, circular in
cross-section, with cross-partitions at regular intervals. Basal leaves few, 1
of the sheaths sometimes lacking a leaf blade. Leaves of the aerial stems 2–4.
Inflorescences racemes or few-branched panicles, the branches mostly ascending,
the leaflike bract at the base shorter than the inflorescence. Flower clusters
mostly 2–10(–20) per inflorescence, mostly spherical, each with 30–100 flowers.
Flowers lacking a pair of closely subtending bracts. Perianth 2.2–3.8 mm long,
the sepals longer than the petals, linear-lanceolate, the tips attenuate.
Stamens 3 per flower. Fruits 1.5–2.7 mm long, 1/2–3/4 as long as the perianth,
narrowly ovate to obconical in outline, the tip abruptly pointed with a small
mucro, 1-locular. Seeds 0.3–0.4 mm long, both ends acute with asymmetrically
darkened points. 2n=44. May–September.
Scattered in the state, mostly south of the Missouri River (eastern U.S. and
adjacent Canada west to Texas). Moist bottomland prairies and along margins of
streams.
The strongly unequal perianth whorls that nearly conceal the relatively short
capsules serve to distinguish this species from morphologically similar taxa,
such as J. nodosus, J. scirpoides, and J. torreyi.