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Vahl's fimbristylis, Vahl's fimbry

ditch fimbry

Habit Plants annual, cespitose, delicate, 4–15 cm, bases soft; rhizomes absent. Plants annual, cespitose, 10–35(–40) cm, glabrous; rhizomes absent.
Leaves

polystichous, mostly spreading or excurved, often exceeding culms;

sheaths entire, abaxially smooth or sparsely hirtellous;

ligule absent;

blades filiform, to 0.5 mm wide, somewhat involute, abaxially glabrous or ascending-strigillose.

polystichous, mostly spreading to ascending;

sheath margins entire;

ligule present, complete;

blades narrowly linear, to 1 mm wide, flat to shallowly involute, margins distantly scabrid, surface glabrous.

Inflorescences

terminal;

spikelets sessile or subsessile in single capitate leafy-involucrate cluster;

scapes filiform;

involucral bracts leafy, setaceous, greatly overtopping inflorescence.

spikelets 1, terminal or 2–3 in simple anthela longer than broad, laterals subsessile;

scapes narrowly linear, coarsely ribbed, distally compressed;

involucral bracts usually 1 per spikelet, exceeding or exceeded by it.

Spikelets

greenish, cylindric to lanceoloid-cylindric, 5–10 mm;

fertile scales narrowly ovate to lanceolate, 1–1.5 mm, acute, glabrous, midrib strong, excurrent as cusp.

yellowish, mostly turgidly ovoid, 5–8 mm;

fertile scales broadly ovate, 2–3 mm, apex obtuse, entire, midrib excurrent or not.

Flowers

stamens 1;

styles 2-fid, slender, bulbous-based, smooth or papillate.

stamens 3, styles 2-fid, flattened, fimbriate.

Achenes

pale, tumidly obovoid, 0.5–0.7 mm, cancellate, pits horizontally rectangular in 5–7 vertical rows per side.

near white to pale brown, lenticular-obovoid to obpyriform, 2 mm, appearing smooth under 10–20X magnification, under higher power finely longitudinally ribbed, with fine, isodiametric pits in vertical lines.

2n

= 20.

= 10.

Fimbristylis vahlii

Fimbristylis schoenoides

Phenology Fruiting summer–fall. Fruiting summer–fall, all year in south.
Habitat Moist to wet, alluvial or mineralized banks, shores, fluctuating pond and lake edges, often a “drawdown” plant around stock tanks and reservoirs Moist sands or sandy peats of roadsides, ditches, flatwoods clearings, savanna, and particularly, disturbed low, open areas
Elevation 0–500 m (0–1600 ft) 1–100 m (0–300 ft)
Distribution
from FNA
AL; AR; AZ; CA; FL; GA; IL; KS; KY; LA; MO; MS; NE; OK; SC; TN; TX; Mexico; Central America; South America
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; LA; MS; tropical Asia; Africa [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
Discussion

Fimbristylis schoenoides is an unusual Fimbristylis for us, with a smooth, “eleocharis-like” appearance. The plants are mostly low and spreading-culmed, glabrous annuals of Asian origin.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 23, p. 127. FNA vol. 23, p. 124.
Parent taxa Cyperaceae > Fimbristylis Cyperaceae > Fimbristylis
Sibling taxa
F. annua, F. autumnalis, F. brevivaginata, F. caroliniana, F. castanea, F. cymosa, F. decipiens, F. dichotoma, F. miliacea, F. perpusilla, F. puberula, F. schoenoides, F. squarrosa, F. thermalis, F. tomentosa
F. annua, F. autumnalis, F. brevivaginata, F. caroliniana, F. castanea, F. cymosa, F. decipiens, F. dichotoma, F. miliacea, F. perpusilla, F. puberula, F. squarrosa, F. thermalis, F. tomentosa, F. vahlii
Synonyms Scirpus vahlii, F. apus, F. congesta, F. vincentii, Isolepis vahlii, Scirpus apus Scirpus schoenoides, F. inconstans
Name authority (Lamarck) Link: Hort. Berol. 1: 287. (1827) (Retzius) Vahl: Enum. Pl. 2: 286. (1805)
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