1. Distichlis spicata (L.) Greene (salt grass)
Pl. 145
e–g; Map 586
Plants perennial, dioecious, with hard, white, scaly
rhizomes, forming colonies. Flowering stems 8–45 cm long, those of pistillate
plants usually somewhat shorter than those of staminate plants, erect from
usually spreading bases, glabrous. Leaves relatively numerous, strongly 2‑ranked
on opposite sides of the stem, the lowermost often reduced to bladeless
sheaths. Leaf sheaths glabrous or hairy toward the tip, the ligule a short
membrane 0.2–0.5 mm long, this minutely hairy along the margin and usually
associated with sparse, longer hairs at the ligule base. Leaf blades 2–12 cm
long, 2–4 mm wide, with loosely inrolled margins, glabrous or roughened to
hairy on the upper surface, narrowed to slender, sharply pointed tips.
Inflorescences dense, narrow panicles 2–8 cm long. Spikelets 8–20 mm long,
strongly flattened laterally, the staminate spikelets with 8–18 fertile florets,
usually not disarticulating, the pistillate spikelets with 4–12 florets,
disarticulating above the glumes, both types similar in morphology, but the
pistillate spikelets with slightly longer glumes, lemmas, and paleas. Lower
glume 1.7–5.0 mm long, lanceolate, sharply pointed at the tip, 5‑ or 7‑nerved
(but the lateral nerves faint), slightly keeled, glabrous. Upper glume 2.4–6.5
mm long, lanceolate, sharply pointed at the tip, 5‑ or 7‑nerved
(but the lateral nerves faint), slightly keeled, glabrous. Lemmas 3.5–7.5 mm
long, sharply pointed at the tip, 7–11‑nerved (but the lateral nerves
faint), awnless, rounded on the back or slightly keeled, thickened and somewhat
leathery, glabrous (including the base). Paleas about as long as the lemmas,
the 2 strong nerves winged. Stamens of staminate spikelets 3, the anthers 2–4
mm long. Fruits 1.8–3.0 mm long, ovate in outline, brown. 2n=40.
June–October.
Uncommon, sporadic in counties adjacent to the Missouri
River (U.S., Canada, Mexico, Central America, South America, Caribbean Islands). Saline marshes and seeps; also railroads and saline, disturbed areas.
Species of Distichlis are adapted to life in moist,
saline soils, where few other plant species can grow. The plants are relatively
unpalatable to livestock, but the fruits (not produced often in some
populations) presumably provide food for waterfowl. Beetle (1943) divided D.
spicata into a series of seven varieties, most of which are no longer
accepted. However, his decision to treat the former D. stricta as a variety
of D. spicata has gained acceptance in much of the recent literature
(Sutherland, 1986; Gleason and Cronquist, 1991). These two taxa are virtually
indistinguishable when only vegetative material is present, except that in var.
spicata the tips of the leaf sheaths tend to be somewhat more hairy and
the tips of the leaf blades tend to be slightly blunted. These differences are
not readily interpretable unless both varieties are available for comparison in
the herbarium. The key and descriptions below are adapted from those in Gleason
and Cronquist (1991).