Part 7 - UNC Herbarium

XYRIDACEAE 947
5 Plants perennial; leaves ascending, green with a distinct brown patch at the base; fruiting spikes ovoid,
blunt, somewhat 2-edged from the strongly keeled outer bracts .........................................X. drummondii
5 Plants annual; leaves flabellate arranged, spreading to recurved against the substrate, usually maroon;
fruiting spikes often elongated and acute, not 2-edged......................................................X. flabelliformis
2 Plants large, usually > 30 cm tall; principal leaves > 10 cm long; mature spikes > 1 cm long when mature.
6 Leaves ascending, twisted, strongly grooved; spikes ovoid, the bracts and lateral sepals with a small tuft of short,
reddish-brown hairs; bases of leaves abruptly expanded, pinkish or purplish (dark brown in age), the outermost
leaves often scale-like, the plant base therefore appearing bulbous; [of the Mountains, Piedmont, and Coastal
Plain]............................................................................................................................................................... X. torta
6 Leaves spreading, not twisted or only slightly so; spikes narrowly ovoid, ellipsoidal, or oblong; bracts and sepals
without a small apical tuft of hairs; bases of leaves whitish, tan, pink, purplish, maroon, or dark brown, the
outermost leaves not scale-like, the plant base not appearing bulbous; [typically of the Coastal Plain, rarely
disjunct inland].
7 Seeds lustrous, translucent, broadly ovoid; spike pale brown or tan, the scales loosely imbricate; plant bases
pinkish, purplish, or tan, with dark longitudinal striations on the inner leaf bases; leaves 3-20 mm wide; petal
blades obovate, 6-7 mm long, opening in early morning, usually closing by mid-day..................... X. ambigua
7 Seeds farinose, dark brown (X. stricta) or pale (X. louisianica) at maturity, narrowly ellipsoid to ovoid; spike
dark brown, the scales tightly imbricate; plant bases maroon, purplish, dark-brown, or reddish-brown; leaves
2-5 mm wide; petal blades triangular-cuneate, 3-5 mm long, opening at mid-day.
8 Seeds pale when mature; plant bases maroon to maroon-brown, solitary or in small clumps; upper end of
scape somewhat flattened, but not nearly as broad as the spike; spike narrowly ovoid to ellipsoid,
slightly pointed......................................................................................................................X. louisianica
8 Seeds dark brown when mature; plant bases dark maroon to dark brown, desnely cespitose; upper end of
the scape conspicuously flattened, almost as broad as the spike; spike oblong-cylindrical, obtuse.............
......................................................................................................................................................X. stricta
1 Keel of the lateral sepals irregularly lacerate or fimbriate, or if entire then the the bract tips not purplish.
9 Leaves narrowly linear to filiform, 0.5-2.0 (-2.5) mm wide, not twisted (or scarcely so); leaf bases expanded, lustrous,
hard, tan to brown, neither bulbous nor deeply set in the substrate; spikes ovoid or ellipsoid, 4-15 mm long.
10 Leaves filiform, terete or elliptic in cross-section, 0.5-1.0 mm wide, without a paler, hardened margin; scape as
broad as or broader than the leaf blades; scales smooth-edged to denticulate, not curled away from the head, the
head thus appearing smooth; staminodia beardless.............................................................................X. baldwiniana
10 Leaves linear, flattened in cross-section, 1-2 (-2.5) mm wide, with a pale, hardened margin; scape usually
narrower than the leaf blades; scales ragged-lacerate, the tips curling away from the head, giving it a ragged
appearance; staminodia bearded.................................................................................................................. X. elliottii
9 Leaves broader, (1.5-) 2.0-25 mm wide, strongly twisted to straight, the leaf bases either not expanded, lustrous, hard,
and tan to brown, or, if so, then the base also either bulbous and/or deeply seated in the substrate; spikes narrowly
lanceolate, ellipsoid, to broadly ovoid, 4-40 mm long.
11 Keel of the lateral sepals long-fimbriate toward its apex, the fimbriate tip conspicuously exserted from the
subtending bract (sometimes eroded and less conspicuous on older spikes).
12 Leaves strongly twisted, 2-5 mm wide; leaf bases hardened, swollen, bulbous, dark lustrous brown; scape
ridges smooth; petal blades white or yellow; [of moist to dry pinelands] ....................................X. caroliniana
12 Leaves not twisted, 5-25 mm wide; leaf bases soft, not swollen, not bulbous, pale; scape ridges strongly
scabrous; petal blades yellow; [of aquatic to very wet peaty, mucky, or sandy ponds, marshes, or other
wetlands]..........................................................................................................................................X. fimbriata
11 Keel of the lateral sepals lacerate, or if very shortly fimbriate, then not conspicuously exserted from the
subtending bract.
13 Lateral sepals longer than and exserted from the subtending bracts; scapes 5-15 dm tall.
14 Leaf blades 1-2 (-3) mm wide, 6-30 cm long; spikes 10-16 mm long; seeds 0.4-0.6 mm long; [endemic
to Panhandle FL and s. AL]............................................................................................... [X. longisepala]
14 Leaf blades 5-15 mm wide; (20-) 30-50 (-60) cm long; spikes 10-20 (-25) mm long; seeds (0.6-) 0.7 (-
0.8) mm long; [more widespread in our area] .........................................................................X. smalliana
13 Lateral sepals shorter than the subtending bracts, and therefore hidden (except when the spikes open to shed
seeds); scapes 1.5-12 dm tall.
15 Scapes flexuous, usually spirally twisted; upper portion of leaf blades conspicuously twisted; plant bases
pinkish, purplish, or dark brown, bulbous or deeply set in the substrate.
16 Base of plant deeply set in the substrate, without distinct outer scale leaves; leaf bases not
noticeably expanded, the plant base therefore not bulbous; leaves smooth, 2-4 mm wide; petal
blades ca. 3 mm long..................................................................................................... X. chapmanii
16 Base of plant shallowly set on the substrate, often with short, black outer scale leaves; leaf bases
noticeably expanded, the plant base therefore appearing bulbous; leaves either smooth and 5-10
mm wide, or scabrous and 2-10 mm wide; petal blades ca. 5 mm long.
17 Leaf and scape surfaces prominently papillose or tuberculate-scabrid; petal blades
suborbicular, yellow; seeds narrowly ovoid or narrowly ellipsoidal, ca. 1.0 mm long................
............................................................................................................................... X. scabrifolia