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hot springs fimbristylis, hot springs fimbry

hairy fimbry

Habit Plants perennial, robust, 50–150 cm, cespitose or with culms solitary; rhizomes scaly, slender, elongate. Plants perennial, mostly loosely cespitose, to 100 cm, bases swollen; rhizomes short, knotty, or scaly, slender, contorted.
Culms

sometimes solitary, narrowly linear, distally angular, glabrous.

Leaves

nearly distichous, spreading to ascending, 1/2 length of culms;

sheath margins entire, backs smooth to pubescent;

ligule present, complete;

blades narrowly linear, proximally flat, 2–3.5(–4) mm wide, margins scabrid-ciliate, abaxial surface sometimes pubescent.

ascending, from 1/3 as long to equally as long as culms, glabrous to pubescent;

sheaths apically ciliate;

ligule essentially absent or (in rhizomatous individuals) present, complete or incomplete;

blades narrowly linear, 1–2 mm wide, mostly strongly involute, scabrid-ciliate.

Inflorescences

anthelae simple or compound, longer than wide;

scapes wandlike, nearly terete or slightly compressed, distally 1 mm thick, marginal ribs scabrid;

longest primary involucral bract shorter than panicle.

anthelae simple or compound, compact or diffuse, mostly broad, ascending-branching;

scapes slender, wandlike, 1 mm thick;

lower leafy involucral bracts exceeded by or exceeding panicle.

Spikelets

pale dull brown, lance-ovoid to cylindric-ellipsoid, 10–12 mm;

fertile scales ovate, 3.5–4 mm, apex broadly acute, ciliate, surface uniformly puberulent, midrib excurrent as mucro or cusp.

variously red-brown, broadly ovoid to lance-cylindric, 5–10 mm;

fertile scales broadly ovate, obtuse or obtuse-angled, 2.5–3.5 mm, abaxially glabrous or variously puberulent, midrib excurrent as mucro.

Flowers

stamens 3;

styles 2-fid, flat, fimbriate.

stamens 3;

styles 2-fid, flat, fimbriate.

Achenes

dark brown, lenticular-obovoid, 1.5 mm, finely cancellate, with 20 or more longitudinal rows of horizontally rectangular pits per side.

yellowish to dark brown, lenticular-obovoid, 1 mm, with 11–20 vertical lines of horizontally rectangular or isodiametric, distinct or indistinct pits.

2n

= 20.

= 20.

Fimbristylis thermalis

Fimbristylis puberula

Phenology Fruiting spring–fall.
Habitat Mineralized sands of hot springs, alkaline seep meadows
Elevation 300–600 m (1000–2000 ft)
Distribution
from FNA
AZ; CA; NV; UT; Mexico (Baja California, Coahuila)
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; AZ; DE; FL; GA; IL; IN; KS; KY; LA; MD; MI; MO; MS; NC; NE; NJ; NM; NY; OH; OK; SC; TN; TX; UT; VA; ON
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

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

Key
1. Culm bases swollen, knotty, closely joined forming short thick, knotty rhizomes; leaves and sheaths totally pubescent or glabrous; ligule absent or incomplete; backs of involucral sheaths and fertile scales puberulent at least distally.
var. puberula
1. Culm bases not swollen, producing several slender, scaly, orange rhizomes; leaves and sheaths mostly glabrous; ligule present, mostly complete; involucral sheaths and fertile scales usually smooth.
var. interior
Source FNA vol. 23, p. 124. FNA vol. 23.
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. tomentosa, F. vahlii
F. annua, F. autumnalis, F. brevivaginata, F. caroliniana, F. castanea, F. cymosa, F. decipiens, F. dichotoma, F. miliacea, F. perpusilla, F. schoenoides, F. squarrosa, F. thermalis, F. tomentosa, F. vahlii
Subordinate taxa
F. puberula var. interior, F. puberula var. puberula
Synonyms Scirpus puberulus
Name authority S. Watson: Botany (Fortieth Parallel), 360. (1871) (Michaux) Vahl: Enum. Pl. 2: 289. (1805)
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