4. Lolium temulentum L. (darnel)
Pl. 178 e;
Map 724
L. temulentum var. macrochaeton A. Braun
L. temulentum f. arvense (With.) Junge
Plants annual, forming tufts. Flowering stems 30–100. Leaf
sheaths with the ligule 0.5–2.5 mm long. Leaf blades 3–27 cm long, 3–10 mm
wide. Inflorescences 10–40 cm long, the axis roughened along the angles.
Spikelets 8–25 mm long (excluding the awns, if present), with 4–9 florets.
Glume 8–30 mm long, as long as or somewhat longer than the rest of the spikelet,
relatively stiff. Lemmas with the body 4.5–8.5 mm long, 2.5–3.0(–3.5) times as
long as wide, oblong‑ovate to oblong‑obovate in outline, bluntly
pointed at the tip, awnless or with an awn 0.3–17.0 mm long. Anthers 2.0–3.5 mm
long. Fruits 4–7 mm long, relatively plump, 2–3 times as long as wide. 2n=14.
May–August.
Introduced, uncommon in western Missouri (native range
unknown; introduced in temperate and subtropical regions nearly worldwide).
Crop fields and open, disturbed areas.
This species is a weed of wheat and other cereal crops whose
origin and natural habitats remain a mystery. Nearly all plants are infected
with endophytic fungi that produce toxic alkaloids (see the paragraph on this
phenomenon at the introduction to the genus Festuca), which can poison
grain harvests if present in sufficient quantities. Infected seeds have been
documented in archaeological finds from ancient Egypt more than 4,000 years old
(Terrell, 1968). The species cannot be divided into varieties or forms based on
presence or absence of awns, as this character varies too much within
individual spikelets. Mühlenbach (1979) noted that the St. Louis record of this
species reported by Steyermark (1963) was based on a misdetermined specimen of L.
persicum.