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ballast sedge, inflated-scale flatsedge

fourangle flatsedge

Habit Herbs, perennial, cespitose, rhizomatous. Herbs, perennial, cespitose, rhizomatous.
Culms

trigonous, 20–100 cm × 0.8–2.5 mm, glabrous.

trigonous, (20–) 30–80 cm × 1–2.5 mm, glabrous or occasionally with scattered prickles on distal angles.

Leaves

5–10, V-shaped to flanged V-shaped, 10–70(–90) cm × 2–7 mm, margins and midribs scabridulous or glabrous.

9–11, flat to slightly V-shaped, 25–80 cm × 3.5–10 mm.

Inflorescences

spikes 1(–6), densely cylindric, 6–30 × 5–11 mm;

rays 3–12, 0.4–5(–7) cm;

rays and rachis glabrous; usually only 1–2 spikes of inflorescence on elongate rays, other spikes sessile or nearly so;

bracts 4–7, horizontal to slightly ascending, 1–16 cm × 0.5–4 mm;

rachilla deciduous, wings persistent, 0.5 mm wide.

spikes (1–)3–6, loosely cylindric or oblong with parallel sides, 1.5–4 cm × 10–17 mm;

rays 6–12, 2–25 cm, glabrous or rarely scabridulous proximal to spikes;

bracts 6–11, ascending at 45°, flat, (1–)10–20(–26) cm × 1–10 mm;

rachilla deciduous, wings persistent, 0.4–0.5 mm wide.

Spikelets

20–80, ellipsoid, roughly quadrangular, 3–5 × 1–1.4 mm;

floral scales 1–2(–4), appressed, stramineous to golden brown, often red-speckled, medially greenish, 9-ribbed, elliptic to ovate, 2.4–3.4 × 1.8–2.6 mm, apex obtuse.

10–60, narrowly ellipsoid, quadrangular, 5–8 × 1.5–2 mm;

floral scales persistent, (2–)3–7, appressed, clear at maturity, laterally reddish to purplish brown, medially greenish, often erose at maturity, laterally 3–5-ribbed, medially 3-ribbed, ovate-elliptic, 2.5–3.2 × 1.8–2.1 mm, apex obtuse.

Flowers

anthers 0.4–0.6 mm;

styles 0.7–1.1 mm;

stigmas 1.4–2.1 mm.

anthers 0.8–1 mm;

styles 0.3–0.5 mm;

stigmas 2–2.5 mm.

Achenes

dark brown to reddish brown, sessile, broadly ellipsoid, 1.8–2.1 × 0.8–1 mm, apex apiculate, surfaces glabrous to finely puncticulate.

brown to reddish brown, sessile, oblong-ovoid to broadly ellipsoid, slightly dorsiventrally flattened, 1.8–2 × 0.7–0.8 mm, apex obtuse, apiculate, surfaces papillose to puncticulate.

Cyperus aggregatus

Cyperus tetragonus

Phenology Fruiting mid summer–fall (Jul–Oct). Fruiting summer–fall (Jun–Nov).
Habitat Dry roadsides, pastures, thickets Open woods, thickets, barrier islands
Elevation 0–500 m (0–1600 ft) 0–1000 m (0–3300 ft)
Distribution
from FNA
AZ; LA; MS; NJ; NM; OR; PA; TX; Mexico; Central America; South America [Introduced, Australia]
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AZ; FL; GA; MS; NC; NM
[WildflowerSearch map]
[BONAP county map]
Discussion

The records of Cyperus aggregatus in New Jersey, Oregon, and Pennsylvania represent introductions from ballast.

The closely related Mexican and Central American Cyperus regiomontanus Britton has been collected once as an adventive or waif in southern California. It is distinguished from C. aggregatus by its silvery green, subulate-lanceolate spikelets and achenes that are only 0.4–0.6 mm wide.

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

The status of Cyperus pringlei from the southwestern United States requires further study.

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

Source FNA vol. 23. FNA vol. 23, p. 189.
Parent taxa Cyperaceae > Cyperus > subg. Cyperus Cyperaceae > Cyperus > subg. Cyperus
Sibling taxa
C. acuminatus, C. alopecuroides, C. amabilis, C. articulatus, C. bipartitus, C. cephalanthus, C. compressus, C. croceus, C. cuspidatus, C. dentatus, C. dentoniae, C. diandrus, C. difformis, C. digitatus, C. dipsaceus, C. distans, C. distinctus, C. drummondii, C. echinatus, C. elegans, C. entrerianus, C. eragrostis, C. erythrorhizos, C. esculentus, C. fendlerianus, C. filicinus, C. filiculmis, C. filiformis, C. flavescens, C. flavicomus, C. floribundus, C. fugax, C. fuligineus, C. fuscus, C. giganteus, C. gracilis, C. granitophilus, C. grayi, C. grayoides, C. haspan, C. hermaphroditus, C. houghtonii, C. hypopitys, C. hystricinus, C. involucratus, C. iria, C. laevigatus, C. lancastriensis, C. lanceolatus, C. lecontei, C. lentiginosus, C. ligularis, C. lupulinus, C. manimae, C. microiria, C. mutisii, C. niger, C. ochraceus, C. odoratus, C. onerosus, C. ovatus, C. owanii, C. oxylepis, C. pallidicolor, C. papyrus, C. parishii, C. pilosus, C. planifolius, C. plukenetii, C. polystachyos, C. prolifer, C. prolixus, C. pseudothyrsiflorus, C. pseudovegetus, C. pumilus, C. reflexus, C. refractus, C. retroflexus, C. retrofractus, C. retrorsus, C. rotundus, C. sanguinolentus, C. schweinitzii, C. serotinus, C. seslerioides, C. setigerus, C. spectabilis, C. sphacelatus, C. sphaerolepis, C. squarrosus, C. strigosus, C. surinamensis, C. tetragonus, C. thyrsiflorus, C. virens
C. acuminatus, C. aggregatus, C. alopecuroides, C. amabilis, C. articulatus, C. bipartitus, C. cephalanthus, C. compressus, C. croceus, C. cuspidatus, C. dentatus, C. dentoniae, C. diandrus, C. difformis, C. digitatus, C. dipsaceus, C. distans, C. distinctus, C. drummondii, C. echinatus, C. elegans, C. entrerianus, C. eragrostis, C. erythrorhizos, C. esculentus, C. fendlerianus, C. filicinus, C. filiculmis, C. filiformis, C. flavescens, C. flavicomus, C. floribundus, C. fugax, C. fuligineus, C. fuscus, C. giganteus, C. gracilis, C. granitophilus, C. grayi, C. grayoides, C. haspan, C. hermaphroditus, C. houghtonii, C. hypopitys, C. hystricinus, C. involucratus, C. iria, C. laevigatus, C. lancastriensis, C. lanceolatus, C. lecontei, C. lentiginosus, C. ligularis, C. lupulinus, C. manimae, C. microiria, C. mutisii, C. niger, C. ochraceus, C. odoratus, C. onerosus, C. ovatus, C. owanii, C. oxylepis, C. pallidicolor, C. papyrus, C. parishii, C. pilosus, C. planifolius, C. plukenetii, C. polystachyos, C. prolifer, C. prolixus, C. pseudothyrsiflorus, C. pseudovegetus, C. pumilus, C. reflexus, C. refractus, C. retroflexus, C. retrofractus, C. retrorsus, C. rotundus, C. sanguinolentus, C. schweinitzii, C. serotinus, C. seslerioides, C. setigerus, C. spectabilis, C. sphacelatus, C. sphaerolepis, C. squarrosus, C. strigosus, C. surinamensis, C. thyrsiflorus, C. virens
Synonyms Mariscus aggregatus, C. cayennensis, C. flavus, C. flavus var. aggregatus, C. flavus var. laevis, Kyllinga cayennensis, Kyllinga squarrosa, Mariscus flavus, Mariscus laevis C. pringlei, C. tetragonus var. pringlei, Mariscus tetragonus
Name authority (Willdenow) Endlicher: Cat. Horti Vindob. 1: 93. (1842) Elliott: Sketch Bot. S. Carolina 1: 71. (1821)
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