Xyris montana
Xyris stricta
northern yellow-eyed-grass, xyris de montagne, xyris des montagnes
pineland yelloweyed grass
compact.
compact.
in narrow fans, 4–15 cm;
sheaths reddish, soft, papillate;
blade deep green, narrowly linear, 0.8–2(–3) mm wide, smooth, margins smooth to papillate.
in narrow fans, 10–60 cm;
sheaths smooth to papillate, base maroon;
blade deep green with red or strong maroon tints, linear-tapering, flat, (2–)4–10 mm wide, smooth or papillate, margins smooth or minutely scabrous, smooth, or papillate.
scape sheaths exceeded by leaves;
scapes linear, wiry, terete, (0.25–)0.5–0.8(–1) mm wide, distally with 2–4 ribs, ribs papillate;
spikes broadly to narrowly ellipsoid or ovoid, 4–8 mm;
fertile bracts 3–4(–4.5) mm, margins erose or minutely fimbriolate, sometimes with narrow reddish border, apex very slightly to slightly keeled.
scape sheaths much exceeded by leaves;
scapes linear, distally oval to ancipital 2-edged, 1.5–3 mm wide, 2–several-ribbed, ribs papillate or minutely scabrous;
spikes ellipsoid to ovoid or cylindric, (10–)15–30 mm, apex blunt to acute;
fertile bracts 5–7 mm, margins entire, apex slightly keeled, convex.
lateral sepals slightly exserted, straight, 4.2–4.7 mm, keel scarious, entire or apically lacerate, apex red, narrow, firm;
petals unfolding in morning, blade obovate, 3–4 mm;
staminodes bearded.
lateral sepals included, reddish brown, curved, 5–7 mm, keel firm, ciliate;
petals unfolding in morning, blade obtriangular, 3–4 mm;
staminodes bearded.
translucent, narrowly ellipsoid, (0.6–)0.7–0.9(–1) mm, finely lined.
mealy, cylindro-fusiform, 0.6–0.8 mm, lined longitudinally with papillae, less distinctly cross-lined.
= 18.
Xyris montana
Xyris stricta
Most or all known populations of this species fall within the boundaries of Wisconsin glaciation. The long stems (a trait not known for other North American species) are a response to the burial of the clump bases in deep sphagnum.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Xyris stricta forms a complex with X. ambigua and possibly arose as an independently breeding hybrid of X. ambigua and X. laxifolia within whose ranges it grows. I have labored since 1966 to determine its taxonomic status and at first believed it to be an extreme of X. ambigua with farinous seeds and smaller petals; then later I determined it to be a distinct species (X. obscura Kral, nom. nud.). Since then I have continued to make field observations and collections of the plant and have arrived at a different conclusion, allowing a more accurate and consistent taxonomy. On the one hand, the plant recently described as X. louisianica ranges to drier habitat than is usual for X. stricta and there commonly mingles with X. ambigua. But in character the plant overlaps most strongly with X. stricta, certainly in habit, pigmentation, leaf shape, bract and sepal character, corolla, and seed. The morphometrics are an indication that these plants have evolved in the Gulf Coastal Plain from X. stricta and are backcrossing with it.
Varieties 2 (2 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Plants 50–90(–104) cm high; leaves 20–60 cm; blade 3–8 mm wide, edges smooth to ciliolate or papillate; scapes distally sharply 2-ribbed, these making edges, but with no or few additional low ribs; ribs smooth, scabrous, or cilioltate; spikes lance-cylindric, or cylindric, 2–3 cm; fertile bracts 6–7 mm; sepals averaging 5–6.5 mm | var. stricta |
1. Plants mostly 40–80 cm high; leaves 20–40 cm; blade (2–)2.5–3(–4) mm wide, edges scabrous or scabro-ciliolate; scapes distally strongly 2-ribbed, these making edges, but with several additional ribs between; all ribs minutely scabrous or papillate; spikes narrowly ovoid, lanceoloid, or ellipsoid, under 2 cm; fertile bracts 5–6.5 mm; sepals averaging 5–6 mm | var. obscura |
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