Flora of North America species comparison

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Eleocharis quinqueflora

Eleocharis tenuis

few-flower spike-rush, few-flower spikesedge, éléocharide à cinq fleurs

dog's hair, slender spike-rush, slender spikesedge
Habit Plants perennial; rhizomes 0.2–1 mm thick, scales persistent or fugaceous, 2–4(–7) mm, thinly membranous, not fibrous; resting buds often present on rhizomes or among culm bases, broadly to narrowly ovoid, 3–6(–10) × 2–5 mm; caudices absent, rarely present, soft or rarely hard, 0.5 mm thick. Plants perennial, mat-forming; rhizomes evident, 0.4–2 mm thick, soft to hard, cortex persistent, longer internodes 2–10 mm, scales persistent or decaying to fibers, 5–10 mm, papery, finely to coarsely fibrous.
Culms

erect, not spirally twisted, not contracted near spikelet, when dry usually with several blunt to acute ridges and sulcate, subterete to slightly compressed, to 2 times wider than thick, 5–35 cm × 0.2–0.5(–1.2) mm, soft to hard;

culm tufts often proximally bulbous (if bulbous then tunicated by papery-fibrous scales).

terete or usually with 4 or 5(–6) angles, often sulcate; 5–90 cm × 0.2–0.5(–0.8) mm, firm to soft.
Leaves

distal leaf sheaths stramineous to brown or reddish proximally, green to stramineous or brown distally, membranous to papery, apex often reddish, subtruncate to acute.

distal leaf sheaths persistent, not splitting, proximally dark red (or yellow-brown), distally green or stramineous or red, membranous, apex often reddish, obtuse to acute, often callose, often with tooth to 0.2(–0.9) mm.
Spikelets

3–8 × 1.5–4 mm;

proximal scale with a flower, seldom empty, 2–5 mm, 1/2 or more as long as spikelet;

floral scales 3–10 per spikelet, 2.5–6 × 1.5–2.5 mm.

ovoid, 3–6 × 1.5–2 mm, apex obtuse to acute;

proximal scale amplexicaulous, apex entire;

subproximal scale with flower;

floral scales appressed in fruit, 20–60, 5–6 per mm of rachilla, medium to dark brown, midrib region often paler, ovate, 1.5–2.5 × 1 mm, apex rounded (to acute), entire, rarely shallowly notched, carinate in distal part of spikelet.
Flowers

perianth bristles (0–)3–6, often unequal, rudimentary to equaling tubercle, stout to slender, spinules dense to apparently absent;

anthers 1.5–2.7(–3.5) mm.

perianth bristles absent or sometimes 1–3, stramineous to pale brown, slender, to equaling achene, obscurely retrorsely spinulose;

stamens 3;

anthers brown, 0.8–1.8 mm;

styles 3-fid.
Achenes

stramineous to medium brown or gray-brown, equilaterally trigonous to compressed-trigonous, rarely some biconvex, obpyriform (to obovoid), 1.6–2.3 × 0.7–1.3 mm, beak variable.

falling with or before scales, lemon yellow, dark yellow, medium brown, or green, obpyriform, trigonous, angles evident, sometimes prominent, 0.6–0.9 × 0.45–0.7 mm, finely to coarsely rugulose and usually alveolate (cancellate) at 10–20X, 6–10(–14) sharp horizontal ridges in each vertical series.
Tubercles

rarely absent, 0.3–0.4 × 0.2–0.3 mm.

brown, pyramidal and to as high as wide to greatly depressed-apiculate, often rudimentary, 0.05–0.3 × 0.25–0.4 mm.

Eleocharis quinqueflora

Eleocharis tenuis
Phenology Fruiting (spring–)summer.
Habitat Fens, wet meadows, seeps, springs, hot springs
Elevation 0–3600 m (0–11800 ft)
Distribution
from FNA
AK; AZ; CA; CO; IA; ID; IL; IN; MA; ME; MI; MN; MT; NE; NH; NJ; NM; NV; NY; OH; OR; PA; UT; VT; WA; WI; WY; AB; BC; MB; NB; NL; NS; NT; ON; PE; QC; SK; YT; Greenland; Eurasia
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CA; CT; DC; DE; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; NB; NS; PE; QC
[WildflowerSearch map]
[BONAP county map]
Discussion

The chromosome numbers for Eleocharis quinqueflora reported for North America (2n = 80) are in doubt because vouchers and other information are lacking. The often-cited n = 10 is probably erroneous. S.-O. Strandhede and R. M. T. Dahlgren (1968) gave 2n = 132 and 134 from Scandinavia. Recognition of infraspecific taxa within E. quinqueflora is premature pending a worldwide revision of subg. Zinserlingia. It has been reported from North Dakota, although I have not seen specimens. About five varieties and subspecies of E. quinqueflora have been described worldwide.

Most specimens from eastern North America and some from the West can be placed in Eleocharis quinqueflora subsp. fernaldii (Svenson) Hultén, which is characterized by its small size (culms to 15 cm × 0.5 mm) and small bulbs. Specimens of E. quinqueflora from 2000–3600 m in California, which are atypical, especially in that the proximal scales of the spikelets do not subtend flowers, may deserve taxonomic recognition. Those plants are also small, with culms only to 15 cm × 0.5 mm; hard caudices are often present at the culm-tuft bases; small, narrowly ovoid bulbs are sometimes present; and perianth bristles are absent or rudimentary. Very few specimens of E. quinqueflora are intermediate with E. suksdorfiana.

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

Varieties 3 (3 in the flora).

The name Eleocharis capitata (Linneaus) R. Brown was long misapplied to E. tenuis (H. K. Svenson 1939). Although the extremes of the three varieties are very different, intermediates are fairly common. Some plants are intermediate with E. elliptica.

Eleocharis tenuis belongs to the E. tenuis complex, which comprises species 16–21 and is restricted to North America, where it is widely distributed except for the Southeast and Southwest. Eleocharis occulta, E. bifida, and E. nitida are very distinct, have little variation, and have relatively restricted ranges; E. tenuis, E. elliptica, and E. compressa are difficult to separate, are highly variable, and have relatively large ranges (see also discussions under E. compressa and E. elliptica). Eleocharis occulta and E. bifida are evidently closely related to E. compressa; they are known only from unglaciated areas south of the limits of Pleistocene glaciation, while E. compressa has a broad range in glaciated regions. The cytotaxonomic study by L. J. Harms (1972) of E. tenuis, E. elliptica, and E. compressa included artificial interspecific and infraspecific hybrids as discussed under those species.

Eleocharis tenuis var. pseudoptera might also be treated as E. elliptica var. pseudoptera following L. J. Harms (1972) because it is intermediate between E. tenuis var. tenuis and E. elliptica var. elliptica in most characters except for the 4-angled, usually deeply sulcate culms. It appears to intergrade with E. elliptica. It is placed in E. tenuis because many plants, including an isotype, are more like E. tenuis than E. elliptica; because most plants key more easily to E. tenuis; and to continue the use of the traditional name. The achenes of the holotype (from Lancaster county, Pennsylvania) and some other specimens closely resemble those of E. elliptica but are not obviously persistent after the scales fall. The usually diagnostic tooth on the distal leaf sheath in E. tenuis var. pseudoptera is also characteristic of E. elliptica var. elliptica; but in E. tenuis var. pseudoptera it is more often present and usually longer and stouter than in E. elliptica. The culms of the holotype of E. tenuis var. pseudoptera and many other specimens are 4- to 5-angled, and in some specimens are very irregularly to 6-angled and often rigid and compressed. L. J. Harms (1972) transferred E. tenuis var. pseudoptera to E. elliptica because he counted the same 2n = 38 chromosome number in both E. elliptica and E. tenuis var. pseudoptera and produced artificial E. elliptica × E. tenuis var. pseudoptera hybrids in which meiotic pairing and pollen stainability were very high. A. E. Schuyler (1977) reported 2n = 39 for E. tenuis var. pseudoptera as well as 2n = 34 and 68 for a putative E. tenuis var. tenuis × E. tenuis var. pseudoptera hybrid.

Putative hybrids between Eleocharis compressa and E. erythropoda of the E. palustris complex in Ontario have been reported (P. M. Catling and S. G. Hay 1993), and I have observed putative E. compressa × E. erythropoda and E. elliptica × E. erythropoda hybrids in the field in southeastern Wisconsin. It seems possible that introgression from E. erythropoda is responsible for some of the variation of both E. compressa and E. elliptica, especially the frequent presence of some 2-fid styles and lenticular achenes in both species and some (rarely all) entire floral scales in E. compressa (S. G. Smith 2001).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Culms sharply angled, usually deeply sulcate, to 0.8 mm wide; some or all culms with distal leaf sheaths with stout apical tooth to 0.4–0.6(–0.9) mm; achenes usually lemon yellow to dark yellow, with 10–14 obscure to clearly evident depressions in each vertical series; tubercles mostly greatly depressed, much lower than wide.
var. pseudoptera
1. Culms bluntly angled to smooth, seldom deeply sulcate, to 0.5 mm wide; distal leaf sheaths without tooth or with slender apical tooth to 0.2 mm; achenes usually yellow to green or brown, with 6–12 depressions in each vertical series; tubercles as high as wide to greatly depressed.
→ 2
2. Rhizomes 0.4–1 mm thick, longer internodes (2–)5–10 mm; tubercles as high as wide, sometimes greatly depressed; achenes finely rugulose and cancellate.
var. tenuis
2. Rhizomes (1–)1.5–2 mm thick, longer internodes 2 mm; tubercles greatly depressed, rarely pyramidal; achenes coarsely (to finely) rugose at 10X and usually cancellate at 10–20X.
var. verrucosa
Source FNA vol. 23, p. 114. FNA vol. 23, p. 86.
Parent taxa Cyperaceae > Eleocharis > subg. Zinserlingia Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Eleocharis
Sibling taxa
E. acicularis, E. aestuum, E. albida, E. ambigens, E. atropurpurea, E. baldwinii, E. bella, E. bernardina, E. bicolor, E. bifida, E. bolanderi, E. brachycarpa, E. brittonii, E. cancellata, E. cellulosa, E. coloradoensis, E. compressa, E. cylindrica, E. decumbens, E. diandra, E. elliptica, E. elongata, E. engelmannii, E. equisetoides, E. erythropoda, E. fallax, E. flavescens, E. geniculata, E. intermedia, E. interstincta, E. kamtschatica, E. lanceolata, E. macrostachya, E. mamillata, E. melanocarpa, E. microcarpa, E. minima, E. montana, E. montevidensis, E. nana, E. nigrescens, E. nitida, E. obtusa, E. obtusetrigona, E. occulta, E. ovata, E. pachycarpa, E. palustris, E. parishii, E. parvula, E. quadrangulata, E. radicans, E. ravenelii, E. retroflexa, E. reverchonii, E. robbinsii, E. rostellata, E. suksdorfiana, E. tenuis, E. torticulmis, E. tortilis, E. tricostata, E. tuberculosa, E. uniglumis, E. vivipara, E. wolfii
E. acicularis, E. aestuum, E. albida, E. ambigens, E. atropurpurea, E. baldwinii, E. bella, E. bernardina, E. bicolor, E. bifida, E. bolanderi, E. brachycarpa, E. brittonii, E. cancellata, E. cellulosa, E. coloradoensis, E. compressa, E. cylindrica, E. decumbens, E. diandra, E. elliptica, E. elongata, E. engelmannii, E. equisetoides, E. erythropoda, E. fallax, E. flavescens, E. geniculata, E. intermedia, E. interstincta, E. kamtschatica, E. lanceolata, E. macrostachya, E. mamillata, E. melanocarpa, E. microcarpa, E. minima, E. montana, E. montevidensis, E. nana, E. nigrescens, E. nitida, E. obtusa, E. obtusetrigona, E. occulta, E. ovata, E. pachycarpa, E. palustris, E. parishii, E. parvula, E. quadrangulata, E. quinqueflora, E. radicans, E. ravenelii, E. retroflexa, E. reverchonii, E. robbinsii, E. rostellata, E. suksdorfiana, E. torticulmis, E. tortilis, E. tricostata, E. tuberculosa, E. uniglumis, E. vivipara, E. wolfii
Subordinate taxa
E. tenuis var. pseudoptera, E. tenuis var. tenuis, E. tenuis var. verrucosa
Synonyms Scirpus quinqueflorus, E. fernaldii, E. pauciflora, E. pauciflora var. fernaldii, E. quinqueflora subsp. fernaldii Scirpus tenuis
Name authority (Hartmann) O. Schwarz: Mitt. Thüring. Bot. Ges. 1: 89. (1949) (Willdenow) Schultes: Mant. 2: 89. (1824)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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