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thread-leaf sedge

Culms

round or trigonous, filiform, wiry, angles proximal to spike blunt or sharp, 5–35 cm, shorter than or longer than leaves.

Leaves

basal leaf sheaths fibrillose when old;

blades yellow-green or bright green, involute-cylindric, quill-shaped, 6–25 cm, 0.3–0.7 mm wide near base.

Spike

7–30 × 3–7 mm, staminate portion 4–14 mm.

Perigynia

(2–)5–18, appressed to ascending, white to gold, obovate to orbiculate, 1.9–4.8 × 1.3–2 mm, body conspicuously hirsute or pubescent, at least distal 1/4 (occasionally only proximal to beak);

beak 0–0.8 mm, style base often conspicuously exserted from beak;

rachilla present.

Achenes

obovate to elliptic, 1.5–3.3 × 1.1–1.9 mm.

Proximal

pistillate scales pale red-brown with white or gold margins, broadly obovate, 2.3–4.5(–6.5) × 1.7–4 mm, shorter or longer than perigynia, apex obtuse to short-awned.

Staminate

scales red-brown with broad, white margins, broadly obovate, apex obtuse.

Stigmas

± black.

Carex filifolia

Distribution
from FNA
AK; AZ; CA; CO; ID; KS; MN; MT; ND; NE; NM; NV; OR; SD; UT; WA; WY; AB; BC; MB; NT; SK; YT
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

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

Key
1. Perigynia (2.8–)3–4.8 mm, beak 0.2–0.8 mm; achene 2.2–3.3 mm; longest pistillate scales (excluding awns) usually equaling or longer than perigynia.
var. filifolia
1. Perigynia 1.9–3 mm, beak absent or less than 0.2(–0.3) mm; achene 1.5–2.3 mm; longest pistillate scales (excluding awns) often shorter than perigynia.
var. erostrata
Source FNA vol. 23, p. 567.
Parent taxa Cyperaceae > Carex > sect. Filifoliae
Sibling taxa
C. aboriginum, C. abrupta, C. abscondita, C. acidicola, C. acutiformis, C. adelostoma, C. adusta, C. aestivalis, C. aggregata, C. alata, C. albicans, C. albida, C. albolutescens, C. albonigra, C. albursina, C. alma, C. alopecoidea, C. amphibola, C. amplectens, C. amplifolia, C. angustata, C. annectens, C. anthoxanthea, C. aperta, C. appalachica, C. aquatilis, C. arapahoensis, C. arcta, C. arctata, C. arctiformis, C. arenaria, C. argyrantha, C. arkansana, C. assiniboinensis, C. atherodes, C. athrostachya, C. atlantica, C. atrata, C. atratiformis, C. atrofusca, C. atrosquama, C. aurea, C. aureolensis, C. austrina, C. austrocaroliniana, C. backii, C. baileyi, C. baltzellii, C. barbarae, C. barrattii, C. basiantha, C. bebbii, C. bella, C. bicknellii, C. bicolor, C. bigelowii, C. biltmoreana, C. blanda, C. bolanderi, C. bonanzensis, C. brainerdii, C. brevicaulis, C. brevior, C. breweri, C. bromoides, C. brunnescens, C. brysonii, C. bulbostylis, C. bullata, C. bushii, C. buxbaumii, C. calcifugens, C. californica, C. canescens, C. capillaris, C. capitata, C. careyana, C. caroliniana, C. caryophyllea, C. castanea, C. cephaloidea, C. cephalophora, C. chalciolepis, C. chapmanii, C. cherokeensis, C. chihuahuensis, C. chordorrhiza, C. circinata, C. collinsii, C. communis, C. comosa, C. complanata, C. concinna, C. concinnoides, C. congdonii, C. conjuncta, C. conoidea, C. constanceana, C. cordillerana, C. corrugata, C. crawei, C. crawfordii, C. crebriflora, C. crinita, C. cristatella, C. crus-corvi, C. cryptolepis, C. cumberlandensis, C. cumulata, C. curatorum, C. cusickii, C. dasycarpa, C. davisii, C. davyi, C. debilis, C. decomposita, C. deflexa, C. densa, C. deweyana, C. diandra, C. digitalis, C. diluta, C. disperma, C. distans, C. disticha, C. divisa, C. divulsa, C. douglasii, C. duriuscula, C. ebenea, C. eburnea, C. echinata, C. edwardsiana, C. egglestonii, C. eleusinoides, C. elliottii, C. elynoides, C. emoryi, C. endlichii, C. engelmannii, C. epapillosa, C. exilis, C. exsiccata, C. extensa, C. festucacea, C. feta, C. fissa, C. fissuricola, C. flacca, C. flaccosperma, C. flava, C. floridana, C. foenea, C. folliculata, C. formosa, C. fracta, C. frankii, C. fuliginosa, C. garberi, C. geophila, C. geyeri, C. gholsonii, C. gigantea, C. glacialis, C. glareosa, C. glaucescens, C. glaucodea, C. globosa, C. gmelinii, C. godfreyi, C. gracilescens, C. gracilior, C. gracillima, C. granularis, C. gravida, C. grayi, C. grisea, C. gynandra, C. gynocrates, C. gynodynama, C. halliana, C. hallii, C. harfordii, C. hassei, C. haydeniana, C. haydenii, C. heleonastes, C. helleri, C. hendersonii, C. heteroneura, C. heterostachya, C. hirsutella, C. hirta, C. hirtifolia, C. hirtissima, C. hitchcockiana, C. holostoma, C. hoodii, C. hookeriana, C. hormathodes, C. hostiana, C. houghtoniana, C. hyalina, C. hyalinolepis, C. hystericina, C. idahoa, C. illota, C. impressinervia, C. incurviformis, C. infirminervia, C. inops, C. integra, C. interior, C. interrupta, C. intumescens, C. jamesii, C. jonesii, C. joorii, C. juniperorum, C. kobomugi, C. kraliana, C. krausei, C. lachenalii, C. lacustris, C. laeviconica, C. laeviculmis, C. laevivaginata, C. lapponica, C. lasiocarpa, C. latebracteata, C. lativena, C. laxa, C. laxiculmis, C. laxiflora, C. leavenworthii, C. lemmonii, C. lenticularis, C. leporinella, C. leptalea, C. leptonervia, C. leptopoda, C. limosa, C. livida, C. loliacea, C. lonchocarpa, C. longii, C. louisianica, C. lucorum, C. lupuliformis, C. lupulina, C. lurida, C. lutea, C. luzulifolia, C. luzulina, C. lyngbyei, C. mackenziei, C. macloviana, C. macrocephala, C. macrochaeta, C. magellanica, C. manhartii, C. marina, C. mariposana, C. maritima, C. mckittrickensis, C. meadii, C. media, C. melanostachya, C. membranacea, C. mendocinensis, C. merritt-fernaldii, C. mertensii, C. mesochorea, C. michauxiana, C. microchaeta, C. microdonta, C. microglochin, C. micropoda, C. microptera, C. misera, C. missouriensis, C. mitchelliana, C. molesta, C. molestiformis, C. muehlenbergii, C. multicaulis, C. multicostata, C. muricata, C. muriculata, C. muskingumensis, C. nardina, C. nebrascensis, C. nelsonii, C. nervina, C. neurophora, C. nigra, C. nigricans, C. nigromarginata, C. normalis, C. norvegica, C. nova, C. novae-angliae, C. nudata, C. obispoensis, C. obnupta, C. obtusata, C. occidentalis, C. oklahomensis, C. oligocarpa, C. oligosperma, C. opaca, C. oreocharis, C. ormostachya, C. oronensis, C. ouachitana, C. ovalis, C. oxylepis, C. ozarkana, C. pachystachya, C. paeninsulae, C. paleacea, C. pallescens, C. panicea, C. pansa, C. parallela, C. parryana, C. pauciflora, C. paysonis, C. peckii, C. pedunculata, C. pellita, C. pelocarpa, C. pendula, C. pensylvanica, C. perdentata, C. perglobosa, C. petasata, C. petricosa, C. phaeocephala, C. picta, C. pigra, C. pityophila, C. planispicata, C. planostachys, C. plantaginea, C. platyphylla, C. pluriflora, C. podocarpa, C. polymorpha, C. praeceptorum, C. praegracilis, C. prairea, C. prasina, C. praticola, C. preslii, C. projecta, C. proposita, C. pseudocyperus, C. pumila, C. purpurifera, C. radfordii, C. radiata, C. ramenskii, C. rariflora, C. raynoldsii, C. recta, C. reniformis, C. retroflexa, C. retrorsa, C. richardsonii, C. roanensis, C. rosea, C. rossii, C. rostrata, C. rotundata, C. rufina, C. rupestris, C. ruthii, C. sabulosa, C. salina, C. sartwelliana, C. sartwellii, C. saxatilis, C. saximontana, C. scabrata, C. scabriuscula, C. schottii, C. schweinitzii, C. scirpoidea, C. scoparia, C. scopulorum, C. senta, C. seorsa, C. serpenticola, C. serratodens, C. sheldonii, C. shinnersii, C. shortiana, C. siccata, C. silicea, C. simulata, C. socialis, C. sparganioides, C. specifica, C. spectabilis, C. specuicola, C. spicata, C. spissa, C. sprengelii, C. squarrosa, C. stenoptila, C. sterilis, C. stevenii, C. stipata, C. straminea, C. straminiformis, C. striata, C. striatula, C. stricta, C. styloflexa, C. stylosa, C. subbracteata, C. suberecta, C. subfusca, C. subnigricans, C. subspathacea, C. superata, C. supina, C. swanii, C. sychnocephala, C. sylvatica, C. tahoensis, C. tenax, C. tenera, C. tenuiflora, C. tetanica, C. tetrastachya, C. texensis, C. thornei, C. thurberi, C. timida, C. tincta, C. tompkinsii, C. tonsa, C. torreyi, C. torta, C. triangularis, C. tribuloides, C. trichocarpa, C. triquetra, C. trisperma, C. tuckermanii, C. tumulicola, C. turbinata, C. turgescens, C. typhina, C. umbellata, C. unilateralis, C. ursina, C. utriculata, C. vacillans, C. vaginata, C. vallicola, C. venusta, C. vernacula, C. verrucosa, C. vesicaria, C. vestita, C. vexans, C. virescens, C. viridula, C. vulpinoidea, C. whitneyi, C. wiegandii, C. willdenowii, C. williamsii, C. woodii, C. wootonii, C. xerantica
Subordinate taxa
C. filifolia var. erostrata, C. filifolia var. filifolia
Name authority Nuttall: Gen. N. Amer. Pl. 2: 204. (1818)
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