6. Juncus brachyphyllus Wiegand (small-headed rush)
Pl.
93 c, d; Map 363
J. kansanus F.J. Herm.
Aerial stems 25–70 cm tall, caespitose, lacking noticeable rhizomes. Leaves
2–7, all basal, 1 or 2 sometimes lacking leaf blades, the auricles at the top
of the sheaths 0.5–1.0 mm long, papery, broadly pointed, the leaf blades 7–35
cm long, 1–2 mm wide, flat or folded longitudinally, lacking cross-partitions.
Inflorescences condensed or less commonly diffuse panicles, the branches mostly
flexuous and ascending, the longest leaflike bract at the base longer than the
inflorescence. Flowers mostly occurring singly or in loose clusters of 2 or 3
near the branch tips, 20–90 per inflorescence, each with a pair of small, ovate
to triangular, rounded or bluntly pointed, closely subtending bracts. Perianth
3.5–6.0 mm long, the sepals as long as or slightly shorter than the petals,
lanceolate, the tips attenuate. Stamens 6 per flower. Fruits 3.0–4.7 mm long,
slightly shorter than the perianth, ovate to broadly oblong in outline, the tip
rounded, 3-locular. Seeds 0.3–0.5 mm long, both ends abruptly tapered to
darkened or translucent points. 2n=ca. 80. June–August.
Uncommon, known only from a few historical collections along the eastern edge of
the Unglaciated Plains Division and the Lincoln Hills (Missouri and Arkansas to
Nebraska and Texas, disjunctly to Washington and California). Sandstone glades
and dry upland prairies on sandstone.
The status of this taxon in Missouri requires further study. It has not been
located in recent years. The report by Steyermark (1963) of a collection from
Pike County is disjunct from the main center of distribution for the species.
Collections from farther west in the Great Plains occur in a variety of
habitats ranging from dry to wet prairies, and even in saline soils.