keys to the vascular plants of east texas - Botanical Research ...

974 POACEAE/LOLIUM
fungus (Neotyphodium lolii, previously in genus Acremonium) that produces toxic alkaloids
(Clay 1988; Yatskievych 1999; Burrows & Tyrl 2001); see detailed discussion of a similar problem
under Festuca arundinacea. In addition, a different fungus can cause a type of photosensitization
in livestock (Burrows & Tyrl 2001). This species is a major cause of hay fever in some
individuals. It has also been pointed out (Myers 2003) that PERENNIAL RYE GRASS is an invasive
exotic that takes over the habitat of native TX wildflowers and reduces their numbers. It is reported
to be cross-pollinated, with only a low degree of self-fertility (Terrell 1966). � I
1. Leaf auricles long, slender, pointed; lemmas usually all with awns to 15 mm long, rarely all awnless
or occasionally only a few in upper spikelets awned; spikelets usually with 10–15(–22)
florets ________________________________________________________________________ var. aristatum
1. Leaf auricles mostly short, rounded; lemmas usually awnless, rarely with awns to 8 mm long;
spikelets with (2–)5–10 florets ______________________________________________________ var. perenne
var. aristatum Willd., (with a stiff awn or bristle), ITALIAN RYE GRASS, ANNUAL RYE GRASS. Annual
or biennial, not producing sterile shoots at base; leaf blades (2–)3-8(–13) mm wide, rolled in
bud. Widespread in TX; throughout most of Canada and the U.S. Native of Europe. [L.
multiflorum Lam., L. perenne var. italicum sensu D.R. Parn., L. perenne var. multiflorum (Lam.)
Thuill. ex Bastard, L. perenne subsp. multiflorum (Lam.) Husn.] This variety is more common in
cultivation than var. perenne. I
var. perenne, PERENNIAL RYE GRASS, ENGLISH RYE GRASS. Perennial but grown as winter annual,
producing sterile shoots at base; usually shorter than var. aristatum and with narrower leaf
blades ((1–)2–4(–6) mm wide) that are folded in bud (Terrell ined.). Widespread in TX; throughout
most of Canada and the U.S. Native of Eurasia. This taxon and var. aristatum are “interfertile
and intergrade” (Terrell ined.). I
Lolium rigidum Gaudin, (rigid, stiff), STIFF RYE GRASS, WIMMERA RYE GRASS. Annual; culms (45–)70
cm or less tall tall; inflorescence to 25(–30) cm long; spikelets 5–18 mm long excluding awns, with
(2–)5–8(–11) florets; glume typically 3/4 as long as spikelet to slightly longer; lemmas usually
awnless, or sometimes with an awn 3(–10) mm or less long. Roadsides and waste places; reported
for Trinity and Walker (Barkworth et al. 2002) cos.; however, we have seen no TX material and
only tentatively consider this species a member of the East TX flora; sc Canada and scattered
locations mostly in the s U.S. (AZ, CA, LA, MO, MS, OR, TX). Spring–summer. [L. perenne L. var.
rigidum (Gaudin) Coss. & Durieu, L. perenne subsp. rigidum (Gaudin) Á & D. Löve, L. strictum
C. Presl, L. subulatum Vis.] Native of the Old World. This species is reported to intergrade with
both L. temulentum and L. perenne and to hybridize with L. perenne var. aristatum (Terrell
ined.). According to Terrell (ined.), “Cattle grazing on L. rigidum that has been infected by a
nematode often develop staggers, but the species is so uncommon in North America that this is
not a serious problem.” The species was also reported as toxic by Kartesz (1999). � I
Lolium temulentum L., (drunken), DARNEL, DARNEL RYE GRASS, BEARDLESS DARNEL RYE GRASS, POI-
SON DARNEL. Annual, forming tufts; culms 30–90(–120) cm tall; ligule 0.5–2.5 mm long; inflorescence
7–28(–40) cm long; spikelets (5–)10–28 mm long excluding awns, with 4–10 florets;
glume (7–)10–25 mm long; lemmas awnless or with an awn usually 5–18(–23) mm long. Roadsides,
sandy weedy areas; widely scattered in East TX; scattered elsewhere in the state; s Canada
and throughout most of the U.S. May–Jun. Native of Eurasia. [L. temulentum var. leptochaeton A.
Braun] This species is reported to be self-pollinating (Terrell 1966; Loos 1993a; Charmet et al.
1996). Gould (1975b) separated awned and awnless forms as varieties; this single character does
not seem worthy of formal recognition, and we are thus here including var. leptochaeton (the
awnless form). This species is poisonous due to alkaloids produced by an endophytic fungus
(probably Endoconidium temulentum Prill. & Delacr.) living intercellularly in the plant tissues,
including the grains. Livestock can be affected with various symptoms, including “rye-grass