Part 7 - UNC Herbarium

XYRIDACEAE 948
17 Leaf and scape surfaces smooth (or scabrous only along margins and ridges); petal blades
obovate, white or yellow; seeds ovoid or ellipsoid, 0.5-0.6 mm long.
18 Seeds translucent; leaf margins smooth; [plants of acidic sites of the Coastal Plain] ..........
......................................................................................................................... X. platylepis
18 Seeds opaque; leaf margins slightly scabrous; [plants of calcareous seeps and fens of the
Ridge and Valley]......................................................................................X. tennesseensis
15 Scapes usually not flexuous, usually not spirally twisted; upper portion of leaf blades not conspicuously
twisted; plant bases variously colored, flabellate or equitant and set at ground level.
19 Summit of the scape distinctly flattened and broad relative to the spike; scape ridges 2-3, the 2 most
prominent comprising the flattened edge of the scape.
20 The 2 principal scape ridges noticeably and abruptly flattened and winglike below the spike,
their combined width (on fresh material) broader than the scape proper; fruiting spikes mostly
8-15 mm long; seeds 0.4-0.6 mm long, translucent, ovoid or ellipsoidal, about 1.5× as long as
wide, with lines of very fine papillae, not farinose...................................................X. difformis
20 The 2 principal scape ridges not abruptly flattened and winglike below the spike, their
combined width < the scape proper, which is itself flattened (narrowly elliptic in crosssection);
fruiting spikes mostly (10-) 20-25 mm long; seeds 0.8-1.0 mm long, dark when ripe,
fusiform to narrowly elliptic, 2-3× as long as wide, with lines of very fine papillae, these
however obscured by a farinose covering................................................................. X. iridifolia
19 Summit of the scape nearly terete or somewhat flattened, much narrower than the spike; scape
ridges several (usually > 3), at least on the mid to lower portion of the scape.
21 Seeds farinose, very dark; surfaces of leaves tuberculate-scabrid, the leaves strongly
ascending, linear, generally > 10 cm long; leaves generally dull-colored.
22 Mature spikes ovoid, sharply acute; plants solitary or in small clumps; leaves 10-30 (-50)
cm long, 1.5-6.0 mm wide, dark maroon or purplish at the base ......................X. floridana
22 Mature spikes ovoid to ellipsoid, acute to obtuse; plants typically in large dense tufts;
leaves 20-50 cm long, 3-12 mm wide, the older ones with dark-brown to gray bases, the
younger with tan bases........................................................................................X. serotina
21 Seeds translucent, not farinose; surfaces of leaves smooth (or sparsely tuberculate-scabrid in
X. curtissii, which also has leaves linear-curvate and generally < 10 cm long); leaves generally
a bright yellowish-green above the base.
23 Leaves broadly linear-curvate, spreading, typically < 10 cm long, 2-4.5 mm wide; plants
perennial, in tufts (rarely solitary); mature spikes acute, with < 10 flowers; leaf bases
pinkish or purplish; old flowers fugacious, not persisting on spikes...................X. curtissii
23 Leaves linear, ascending, 10-60 cm long, 5-10 mm wide; plants annual, solitary or in
small tufts; mature spikes obtuse, many-flowered; leaf bases tan (very rarely pinkish); old
flowers often persistent on the spikes, drying blackish.........................................X. jupicai
Xyris ambigua Beyrich ex Kunth. Cp (GA, NC, SC, VA), Pd (NC), Mt (VA): wet savannas and flatwoods, pinelands,
edges of depression ponds; common. June-August. Se. VA south to FL, west to AL and ec. TX, primarily on the Coastal Plain.
[= RAB, C, F, FNA, G, K, W, X; < X. ambigua – GW, S, Z (also see X. louisianica)]
Xyris baldwiniana J.A. Schultes, Grassleaf Yellow-eyed Grass. Cp (GA, NC, SC), Pd (NC): wet savannas, seepage bogs,
sandhill seeps, wet savanna ecotones; rare (NC Watch List). June-July. Se. NC south to n. FL, west to s. AR and ec. TX,
primarily on the Coastal Plain. [= RAB, FNA, GW, K, S, X, Z]
Xyris brevifolia Michaux, Shortleaf Yellow-eyed Grass. Cp (GA, NC, SC): wet sands of pinelands, especially seasonally
wet, open, white sands of spodosol longleaf pine flatwoods (Leon series soils), margins of Carolina bay sandrims; rare (NC Rare,
SC Rare). June-August. Se. NC south to s. FL, west to s. AL and w. FL; West Indies and South America. [= RAB, FNA, GW,
K, S, X, Z]
Xyris caroliniana Walter, Pineland Yellow-eyed Grass. Cp (GA, NC, SC, VA): dry to moist pine flatwoods, moist
savannas, scrub oak sandhills; common (VA Rare). June-July. Se. VA south to FL, west to se. TX, and disjunct northward in s.
NJ. White-petaled populations of X. caroliniana occurring in the East Gulf Coastal Plain need additional study. [= RAB, C,
FNA, GW, K, X, Z; > X. flexuosa Muhlenberg ex Elliott – F, G, S; > X. pallescens (C. Mohr) Small – S]
Xyris chapmanii Bridges & Orzell, Chapman's Yellow-eyed Grass. Cp (GA?, NC, SC): sandhill seepage bogs in areas of
copious lateral seepage in deep muck soils; rare (NC Rare). Sc. NC south to panhandle FL, west to e. TX. This taxon is
abundantly distinct from X. scabrifolia. [= X; < X. scabrifolia – FNA, K, Z]
Xyris curtissii Malme, Curtiss's Yellow-eyed Grass. Cp (GA, NC, SC, VA), Pd (SC): savannas; rare (NC Watch List, VA
Rare). July-August. Se. VA south to n. FL and west to s. AR and ec. TX, primarily on the Coastal Plain; disjunct in s. NJ. [=
RAB, G; = X. difformis Chapman var. curtissii (Malme) Kral – C, FNA, GW, K, X, Z; > X. bayardii Fernald – F; > X. curtissii –
F; ? X. neglecta Small – S]
Xyris difformis Chapman. Cp (GA, NC, SC, VA), Pd (GA, NC, SC), Mt (NC): savannas, roadside ditches, pond margins,
other wet habitats; common (VA Watch List). August-October. New England and s. Canada south to n. FL and ec. TX. [= X; =
X. difformis Chapman var. difformis – C, FNA, GW, K, Y, Z; < X. difformis – RAB, F, G, S, W (also see X. curtissii)]
Xyris drummondii Malme, Drummond's Yellow-eyed Grass. Cp (GA): wet pine flatwoods, ditches; uncommon. Se. GA
south to Panhandle FL, west to s. MS. [= FNA, GW, K, X, Z]