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ISSN 1188-603X

No. 375 March 14, 2007	aceska@telus.net	Victoria, B.C.

Dr. A. Ceska, P.O.Box 8546, Victoria, B.C. Canada V8W 3S2

ELEOCHARIS IN BRITISH COLUMBIA: SPECIES DESCRIPTIONS, KEY, AND E. NITIDA NEWLY REPORTED FOR B.C.

From: S. Galen Smith, Department of Biological Sciences, University of Wisconsin-Whitewater (Emeritus); Department of Botany, University of Wisconsin-Madison (Honorary Fellow). 218 DuRose Terrace, Madison, WI 53705, U.S.A. [sgsmith2@wisc.edu]

In the mid-1990's I accepted the invitation to be in charge of the treatment of Eleocharis for the Flora of North America (FNA) project in addition to preparing the treatments of four genera segregated from Scirpus sensu lato, even though I had no experience with Eleocharis. Although Svenson’s pioneer studies (Svenson 1929, 1932, 1934, 1937, 1939, 1947, and 1957) provided a good basis for my work, I soon discovered that I had to do an enormous amount of basic taxonomic work on six very difficult species groups in addition to all of the other chores of producing a unified treatment of the genus. Although I could not study all specimens from all herbaria, I did borrow specimens from the University of British Columbia (UBC) and the Royal British Columbia Museum (V), and here thank the kind assistance of the curators of those herbaria for their help.

The main purpose of this paper is to provide a key and descriptions for just the species of Eleocharis known to occur in British Columbia to make it easier to identify specimens from there because my huge key in FNA is so extremely complex that it is very difficult to use. Secondary purposes are to highlight taxonomic problems among these species and provide other useful information not included in FNA.

Also, the presence of Eleocharis nitida is here reported for the first time for B.C. Major credit for this report belongs to S. Frank Lomer, who collected E. nitida in B.C. in 1997, and informed me in 2005 that two collections that I had annotated as E. nitida but overlooked while preparing my FNA treatment are in the herbarium of the University of Minnesota herbarium. I have only seen these three specimens of E. nitida from B.C.: B.C., Silvertip Mt., Skagit Range, Cascade Mts., ca. 18 km NNW of Ross Lake, 48deg08’70”N 121deg14’10”W, springy mossy sod from fresh water seep, elev. ca. 3300 feet, 4 Aug 1997 (but grown in pot until pressed on 11 Sep 1997), F. Lomer 97-592 (WIS); B.C., Glacier Brown rocks (late schist), base of Avalanche Crest, 4800 ft, Sept. 1920, F.K. Butters (MIN 240428); B.C., Glacier, swamps by Government Road, 4000 ft, 30 July 1913, F.K. Butters (MIN 240726). The diminutive and easily overlooked E. nitida, which is closely related to the also remarkable E. elliptica, seems to be a very good species. It is restricted to boreal North America, with a wide but markedly disjunct distribution across the continent. To my knowledge, the known localities nearest to those in B.C. are in northeastern Saskatchewan and on Kodiak Island.

In the descriptions herein the items in brackets refer to information from outside of B.C.; measurements of plant structures are mostly taken from my treatment (and Francis J. Menapace’s for E. atropurpurea) in the Flora of North America (Smith 2002, Menapace 2002). The format I have used for the descriptions is that being used by the editors of the upcoming The Jepson Manual of the Higher Plants of California ed. 2, for which I am preparing the treatment of Eleocharis.

Eleocharis taxa in British Columbia:

A. Eleocharis palustris group: Subg. Eleocharis sect. Eleocharis ser. Eleocharis, in part
1. Eleocharis palustris
2. Eleocharis mamillata
3. Eleocharis macrostachya
4. Eleocharis erythropoda
5. Eleocharis uniglumis
6. Eleocharis kamtschatica
B. Eleocharis tenuis group: Subg. Eleocharis sect. Eleocharis ser. Eleocharis, in part
7. Eleocharis elliptica
8. Eleocharis compressa var. acutisquamata
9. Eleocharis nitida
C. Subg. E. rostellata sect. Eleocharis ser. Rostellatae
10. Eleocharis rostellata
D. E. quinqueflora group: Subg. Zinserlingia
11. Eleocharis suksdorfiana
12. Eleocharis quinqueflora
E. E. acicularis group: Subg. Scirpidium
13. Eleocharis acicularis
F. E. parvula group: Subg. Eleocharis Sect. Parvulae
14. Eleocharis parvula
G. E. atropurpurea group: Series Maculosae: Subg. Eleocharis sect. Eleogenus Ser. Maculosae
15. Eleocharis atropurpurea
H. E. ovata group: Subg. Eleocharis sect. Eleogenus Ser. Ovatae
16. Eleocharis engelmannii
17. Eleocharis obtusa
18. Eleocharis ovata

Eleocharis

COMMON NAME: SPIKE-RUSHES
PLANTS annual or perennial, tufted or generally forming mats, glabrous, with evident internal air cavities; caudex sometimes present; rhizomes present or absent, long (or short), scaly, tip rarely with a bulb or tuber.
STEM (CULM) unbranched, generally erect, smooth, [sometimes hollow with complete cross-partitions], tip rarely rooting.
LEAVES 2, basal, blade absent or rarely rudimentary.
INFLORESCENCE: Bract absent; spikelet 1, terminal on culm, generally ovoid, [rarely compressed], 3- to 100+ flowered, [rarely forming plantlets]; basal scale completely encircling stem or not, generally less than ½ as long as spikelet, flower absent (or present); scales spiraled [rarely 2-ranked], generally ovate, generally brown, generally membranous, smooth, tip generally acute to obtuse, entire (rarely notched or bifid), midrib not prolonged.
FLOWER bisexual, 1 per scale; perianth bristle-like, 0–8, persistent, rudimentary to ca. equaling tubercle, retrorsely [to antrorsely] barbed or sometimes smooth; stamens 3 (or fewer); style 1, thread-like, base generally enlarged and persistent on mature achene as the tubercle.
TUBERCLE generally clearly distinct from achene, or sometimes merging with and hard to distinguish from achene summit, much smaller than- to about as large as achene.
FRUIT: An achene, generally obovoid, generally brown, surface smooth or sometimes finely rugulose or with several prominent and many fine horizontal bars [or rows of pits].
SPECIES IN GENUS and RANGE: ca. 200, boreal to tropical worldwide.
ETYMOLOGY: Greek heleios, dwelling in a marsh, and charis, grace
ECOLOGY: Mesotrophic and eutrophic (or brackish) wetlands.

Key to the species

1. Plants mat-forming; rhizomes present; stigmas 2 or 3; fruit lenticular or trigonous; perennials ...................................... 2
1. Plants tufted; rhizomes absent; stigmas 2; fruit lenticular; annuals (rarely perennial?) ..............................................15

2. Distal leaf sheath firmly membranous to papery, persistent; stem 0.2–2.5 mm thick; plants large to sometimes small ..........................................3
2. Distal leaf sheath delicately membranous, often disintegrating; stem 0.2–0.5 thick; plants generally very small ..................... ...........................14

3. Stigmas 2; fruit lenticular; spikelet basal scale without a flower; tubercle clearly distinct from fruit summit; spikelet basal scale without a flower; rhizome evident, horizontal (E. palustris group) ............................................. 4
3. Stigmas 3 or some 2 in same spikelet; fruit trigonous or some lenticular in same spikelet; spikelet basal scale sometimes with a flower; tubercle sometimes merging with fruit summit; rhizome evident and horizontal or rarely hidden among stem bases and ascending .................................... .9

4. All spikelets with basal scale completely clasping stem and 2nd scale with a flower ...................................................5
4. Some or all spikelets with basal scale not completely clasping stem and/or with 2nd scale without a flower .............7

5. Tubercle 2/3 or more as high as and 2/3 as wide as fruit, 0.7 mm or more high, 0.8 mm or more wide; spikelet scales 1–2 per mm of rachilla; coastal ........................................ 6. E. kamtschatica
5. Tubercle less than 2/3 as high and as wide as fruit, 0.8 mm or less high, 0.8 mm or less wide; spikelet scales 2–5 per mm of rachilla; often inland ...........6

6. Spikelet scales 2–3 (–4) per mm of rachilla, 1.8--2+ mm wide (best measured by viewing the scale, while still in the spikelet, from the side, and measuring the width from one margin to the middle then doubling the measurement) ....5. E. uniglumis
6. Spikelet scales 4–5 per mm of rachilla, ca. 1.7 mm or less wide .... 4. E. erythropoda

7. All spikelets with basal scale clasping 2/3 (to 3/4) of stem and 2nd scale without a flower; perianth bristles 0–4(5–8) .......................8
7. Some or all spikelets with basal scale clasping 3/4 to all of stem; some spikelets with 2nd scale with a flower; perianth bristles 4(–5) ......3. E. macrostachya

8. Perianth bristles 0--4(–5), much shorter than to rarely exceeding tubercle (rarely to 2X longer than fruit); tubercle often not sessile on achene .... 1. E. palustris
8. Perianth bristles (4–)5–6(–8), mostly much exceeding tubercle, to 2X longer than achene; tubercle sessile on achene ................ 2. E. mamillata

9. Some stems greatly elongating and tips rooting to form new plants; rhizomes short, ascending, hidden by culm bases and roots; stems compressed, generally hard, 0.4–2 mm wide; fruit 1.5–2.5 mm; tubercle generally not clearly differentiated from fruit (series Rostellatae) ............................................... 10. E. rostellata
9. All stems about the same length, tips not rooting; rhizomes long, horizontal, evident; stems cylindric (to compressed), 0.1–1 mm wide; fruit 0.5–1.2 mm; tubercle clearly differentiated from fruit or not ...........10

10. Rhizomes tough; spikelet basal scale without a flower, much less than ½ as long as spikelet, scales (5–)10–80 per spikelet, scale tip often notched or bifid; tubercle clearly differentiated from fruit; bulbs absent (subg. Eleocharis sect. Eleocharis ser. Eleocharis, in part) ........................................................... 11
10. Rhizomes weak, easily broken (thus often not collected); spikelet basal scale with- or without a flower, generally ½ or more as long as spikelet, scales 4–12 per spikelet, scale tip entire; tubercle not clearly differentiated from fruit; bulbs often present at rhizome tips and culm-tuft bases (subg. Zinserlingia) .....13

11. Spikelet scales 1–1.3 mm, tip entire; stems 0.1--0.3 mm thick; fruit 0.5–0.6 mm; plants to 15 cm high .............................. 9. E. nitida
11. Spikelet scales 2–3.5 mm, tip entire or notched or bifid; stems (0.2–)0.3–1 mm thick; fruit 0.7–1.1 mm; plants to 90 cm high ...........................12

12. Spikelet scale tips narrowly acute to acuminate; fruit falling with scales or some persistent .................. 10. E. compressa var. acutisquamata
12. Spikelet scale tips rounded to acute; fruit persistent in spikelets after scales fall (often throughout the winter) .............. 11. E. elliptica var. elliptica

13. Stem-tuft bases mostly markedly swollen; bulbs often present (one among stem bases, one on each rhizome tip, and several on tips of very short rhizomes at surface of stem-tuft base); stem-tuft base without hard caudex [or sometimes present in high Sierra of California and in Europe]; perianth bristles 0–6, rudimentary to exceeding fruit ................................................................. 12. E. quinqueflora
13. Stem-tuft bases not markedly swollen, bulbs absent; stem-tuft base with hard caudex; perianth bristles 6, all equaling or exceeding fruit ........ 11. E. suksdorfiana

14. Spikelet with basal scale with a flower; fruit with 6–12 longitudinal ridges and many fine horizontal bars between ridges; tubers absent (subg. Scirpidium) ......................................... 13. E. acicularis
14. Spikelet with basal scale without a flower; fruit with 3 longitudinal angles, horizontal bars absent; tuber often present on rhizome tip (subg, Eleocharis sect. Parvulae) ........................................... 14. E. parvula

15. Fruit 0.3–0.5 mm, black when ripe; tubercle base not completely adherent to fruit, not dorsoventrally compressed (sect. Eleogenus series Maculosae) ......................................... 15. E. atropurpurea
15. Fruit 0.7–1.2 mm, brown when ripe; tubercle base completely adherent to fruit, greatly dorsoventrally compressed (sect. Eleogenus series Ovatae) ..........16

16. Tubercle 0.1–0.3 mm high, 1/4 or less as high as fruit; perianth bristles ca. equaling tubercle or rudimentary .............................. 16. E. engelmanii
16. Tubercle 0.3–0.5 mm high, 1/3 or more as high as fruit; perianth bristles exceeding tubercle ..........................................17

17. Tubercle (0.4–) 0.5–0.8 mm wide, 1/3 to 2/3 as high as wide, 2/3–9/10 as wide as fruit ........................................ 17. E. obtusa
17. Tubercle 0.2–0.5 mm wide, 3/5 to fully as high as wide, ½–3/4 as wide as fruit ................................................ 18. E. ovata

A. Eleocharis palustris group: Eleocharis subg. Eleocharis sect. Eleocharis series Eleocharis subseries Eleocharis
Plants perennial, generally robust, mat-forming; rhizomes long, generally tough, with long internodes not covered by scales; stigmas 2, or rarely some 3 in same spikelet; tubercle rarely completely appressed to achene, pyramidal to mamillate; fruit lenticular, smooth or sometimes obscurely rough, rarely rugulose. A taxonomically difficult circumboreal complex that is well-known only in western Europe, owing to the extensive studies of S.-O. Strandhede. This group includes the most common Eleocharis species in most of North America as well as several rare species that occupy special habitats. REFERENCES: Bures (1998, 2002); Harms (1968); Menapace (1993); Strandhede (1965, 1966, 1967); Strandhede & Dahlgren (1968); Walters (1953, 1967, 1980).

1. Eleocharis palustris (L.) Roemer & Schultes
PLANTS perennial, 30–100 [--115] cm; rhizome1.5–4.5 mm thick.
STEM sub-cylindric, 0.5 to ca. 3 mm thick
LEAVES: Distal sheath firmly membranous to papery, persistent, tip obtuse to acute.
INFLORESCENCE: Spikelet 5–25 x 3–7 mm; basal scale clasping 2/3–3/4 of stem; 2nd scale without a flower; scales 30–100 per spikelet, 3–5 x 1.5–2.5 mm, 4–8 per mm of rachilla.
FLOWER: Perianth bristles (0) 4 (--5), much shorter than- to equaling tubercle or rarely to 2X longer than fruit; anthers 1.5–2.2 mm.
TUBERCLE from as high as wide to 2X higher, 0.3–0.7 x 0.3–0.7 mm.
FRUIT lenticular, 1.1–1.5 [–2] x 1–1.5 mm, smooth or finely rough.
CHROMOSOME NUMBER: 2n = 16, 17, 36.
ECOLOGY: Common. Fresh ponds, shores, marshes, wet meadows, slow rivers, often emergent.
ELEVATION: 50–1600 [--3000] m.
DISTRIBUTION: Boreal and temperate N. Am. except far Southeast; Mexico, Eurasia, New Zealand.
FLOWERING TIME: Summer.
NOTE: Eleocharis palustris is very variable. Most B.C. plants are very similar to many Eurasian plants. Some plants with very narrow tubercles to 2 times higher than wide closely resemble some eastern Asian plants. A few plants in western N.Am. are intermediate with E. macrostachya, and in the East with E. erythropoda. Eleocharis palustris var. vigens L.H. Bailey, currently known only from northeastern North America, is especially robust and is characterized by large fruit 1.6–2 mm long and large culm stomates and is assumed to be a polyploid with 2n = 36.
SYNONYMS: Eleocharis smallii Britton; Scirpus palustris L.

2. Eleocharis mamillata (Lindb. fil.) Lindb. fil. subsp. mamillata
PLANTS perennial, 10–50 cm; rhizome long, 0.7–1 mm thick.
STEM cylindric, 0.5–3 mm thick, very soft (pressing very flat).
LEAVES: Distal sheath firmly membranous, persistent, tip obtuse.
INFLORESCENCE: Spikelet 5–20 x 3–5 mm; basal scale encircling 2/3 of stem; 2nd scale without a flower; scales 15–80, 2.5–4 mm, ca. 5 per mm of rachilla.
FLOWER: Perianth bristles (4--)5–6(–8), mostly exceeding tubercle, to 2X longer than fruit; anthers 0.9--1.5 mm; stigmas 2.
TUBERCLE pyramidal to mamillate, lowerthan to as high as wide, 0.2–0.6 x 0.4–0.6 mm.
FRUIT: lenticular, 1–1.4 x 0.9–1.3 mm, smooth.
CHROMOSOME NUMBER 2n = 16 (B.C., Europe).
ECOLOGY: Very local. Fresh shallow ponds, streams, floating mats, bogs, fens, ditches.
ELEVATION: 20–830 m.
DISTRIBUTION: Boreal and north-temperate; s Alaska and n Washington to s Quebec; Eurasia.
FLOWERING TIME: Summer.
NOTES: Eleocharis mamillata was long thought to be restricted to northern Europe, but recent studies reveal it to be circumboreal. It closely resembles E. palustris, but no intermediates are known in North America. All North American plants are referable to E. mamillata subsp. mamillata, but in Eurasia E. mamillata subsp. austriaca (Hayek) Strandhede and E. mamillata subsp. ussuriensis (Tsinserling) Y.L. Chang are recognized for the former USSR (Egorova 1981). The name E. mamillata was long misapplied in North America to E. macrostachya. The stamen filaments remain attached to the shed achenes, and together with the long bristles they connect the achenes into ball-like aggregates that drift with winds and water currents (S.-O. Strandhede 1966). The chromosome count of 2n = 16 reported from the Queen Charlotte Islands by Taylor & Mulligan (1968, p. 40-41) under E. macrostachya was based on a misidentified collection of E. mamillata (Calder & Taylor 23666).

3. Eleocharis macrostachya Britton
PLANTS perennial, 20–100 cm; rhizome 1–2 mm thick.
STEM cylindric [to compressed], 0.5–2.5 (–3.5) mm thick.
LEAVES: Distal sheath firmly membranous, persistent, tip truncate to obtuse [sometimes with tooth-like rudimentary blade less than 1 mm long].
INFLORESCENCE: Spikelet 5–40 x 2–5 mm; basal scale clasping from 3/4 to all of stem; 2nd scale in some spikelets with a flower, in other spikelets without a flower; scales 30–80, 2.5–5.5 mm, 3–5 per mm of rachilla.
FLOWER: Perianth bristles 4 (--5), rudimentary to equaling tubercle; anthers 1.3–2.7 mm.
TUBERCLE as high as- or sometimes much higher than wide, 0.35–0.7 x 0.25–0.7 mm.
FRUIT lenticular, 1.1–1.9 x 0.8–1.5 mm, smooth or finely rough.
CHROMOSOME NUMBER 2n = 18, 19, 38.
ECOLOGY: Common. Fresh (to brackish) marshes, shores, ponds, wet meadows, creek margins, tidal flats, blanket bog.
ELEVATION: 0–1200 m.
DISTRIBUTION: Boreal and temperate N.Am.; Alaska to California to w Quebec, w Wisconsin, Mississippi; Mexico, S. Am.
FLOWERING TIME: Late spring to summer.
NOTE: Very variable. B.C. plants are intermediate between E. palustris and E. erythropoda or between E. palustris and E. uniglumis. Many coastal plants are very similar to E. uniglumis. It seems possible that the polyploid populations of E. macrostachya are synonymous with E. palustris subsp. vulgaris Walters, which is recognized in Europe, and is probably an allopolyploid originating by hybridization between E. palustris and E. uniglumis (Strandhede 1966).
SYNONYM: Eleocharis perlonga Fernald & Brackett.

4. Eleocharis erythropoda Steudel
PLANTS perennial, 8–80 cm; rhizome long, tough, 0.5–1.5 mm thick.
STEM sub-cylindric, 0.3–1.4 mm thick.
LEAVES: Distal sheath firmly membranous, persistent, tip broadly obtuse to subacute.
INFLORESCENCE: spikelet 3–18 x 2–3(–4) mm; scales 15–50, 2–3.5 x ca. 1.5–1.7 mm.
FLOWER: perianth bristles 4 or 0, ca. equaling fruit or slightly exceeding tubercle; anthers 1–1.8 mm; stigmas 2.
TUBERCLE pyramidal, much higher than- to lower than wide, 0.35–0.65 x 0.2–0.6 mm.
FRUIT lenticular, 0.9–1.6 x 0.7–1.2 mm, smooth or finely rugulose.
CHROMOSOME NUMBER 2n = 16, 18, 19, 20.
ECOLOGY: Very local in B.C. Fresh shores, streams, marshes, meadows, disturbed places.
ELEVATION: [0—2300 m]
DISTRIBUTION: N.Am. except far Southeast; rare in Far West (Alaska to California), abundant in the East.
FLOWERING TIME: Summer, fall.
NOTES: E. erythropoda closely resembles some slender plants of E. uniglumis, and intermediates with E. macrostachya are common in western N.Am.
SYNONYMS: Scirpus glaucus Torrey, not Lam. 1791 or Bock 1871; Eleocharis calva Torrey, illeg. (The application of the name E. erythropoda may be in doubt; the illegitimate name Eleocharis calva Torrey was generally used until 1957 when Svenson, in his revision in North American Flora 18, part 19, p. 525, replaced it with E. erythropoda without explanation.)

5. Eleocharis uniglumis (Link) Schultes
PLANTS perennial, 10–60 cm; rhizome long, tough, 0.3–1 mm thick.
STEM cylindric, 0.2–1.5 mm thick.
LEAVES: Distal sheath persistent, firm, tip obtuse to subacute.
INFLORESCENCE: Spikelet 5–10 x 2–3(–4) mm; basal scale without a flower, 2nd scale with a flower; scales 10–20, 3–4 per mm of rachilla, 3–4 x 1.8–2.5 mm.
FLOWER: Perianth bristles 0–4(–5), rudimentary to equaling fruit; anthers 1.2–2 mm; stigmas 2.
TUBERCLE much higher than- to slightly lower than width, 0.4–0.8 x 0.3–0.8 mm, sometimes spongy and with vertical rows of depressions.
FRUIT lenticular, 1.3–1.8 x 1–1.4 mm, smooth or finely rugulose at 10–20X.
CHROMOSOME NUMBER 2n = 27, 28 (reported from Massachusetts and Nebraska, but vouchers not seen by me); [(44–)46(47–88) reported from Europe].
ECOLOGY: Very local. Mostly coastal brackish (to fresh) shores, marshes, fens.
ELEVATION: 0–1750 m.
DISTRIBUTION: B.C. and N.W.T. to Nfld.; Nevada and North Dakota to New Mexico; Atlantic Coast to North Carolina; Eurasia.
FLOWERING TIME: Summer.
NOTES: Eleocharis uniglumis is very variable in both North America and Eurasia. It closely resembles some plants of E. macrostachya (especially along the Pacific Coast) and E. erythropoda. Some plants are intermediate with E. kamtschatica.
SYNONYMS: Eleocharis halophila (Fernald & Brackett) Fernald; E. uniglumis var. halophila Fernald & Brackett; Scirpus uniglumis Link.

6. Eleocharis kamtschatica (C.A. Meyer) Komarov
PLANTS perennial, 10–60 cm; rhizome long, soft, 0.5–1.5 mm thick.
STEM cylindric, 0.3–1.8 mm thick.
LEAVES: Distal sheath persistent, firm, tip obtuse to acuminate.
INFLORESCENCE: Spikelet 4–20 x 3–6 mm; proximal scale amplexicaulous, without a flower, 2nd scale with a flower; scales 5–20, 2.5–5 x 2–2.5 mm, 1–2 per mm of rachilla.
FLOWER: Perianth bristles 0–6(–9), much shorter than- to equaling fruit; anthers 1.3–2.5 mm; stigmas 2.
TUBERCLE (0.5–)0.7–1.5 x (0.5--)0.8–1.4 mm, usually spongy with vertical rows of depressions.
FRUIT lenticular, 1–1.5(--1.9) x 1–1.6 mm, finely reticulate at 20X to 30X or rugulose with 20 or more horizontal ridges.
CHROMOSOME NUMBERS 2n = 12 (from Queen Charlotte Islands) [2n = 38, 40, 42, 56 reported from eastern Asia].
ECOLOGY: Uncommon. Coastal brackish (to fresh) shores, marshes [and inland hot springs in Asia].
ELEVATION: 0–30 m
DISTRIBUTION: Alaska, B.C., Manitoba, Quebec, Newfoundland and Labrador; eastern Asia.
FLOWERING TIME: Summer.
NOTE: North American Eleocharis kamtschatica seems to be separable into two groups: 1) Relatively small plants, including the voucher for the single 2n = 12 chromosome count, and 2) relatively large plants, possibly with higher chromosome counts as reported from Asia. It
closely resembles some plants of E. uniglumis, which differs mainly in its smaller tubercles.
SYNONYMS: Scirpus kamtschaticus C. A. Meyer

B. Eleocharis tenuis group: Subg. Eleocharis section Eleocharis series Eleocharis, in part
Plants medium-sized or small, perennial, mat-forming; rhizomes generally with short internodes that are sometimes obscured by scales; spikelet basal scale without a flower; stigmas all or mostly 3; fruit all or mostly trigonous, obscurely to prominently rugulose and/or pitted. The Eleocharis tenuis group is restricted to North America and is comprised of 6 species, of which E. elliptica, E. compressa and E. tenuis are very variable and comprise an extremely difficult complex in which species delimitation is arbitrary, while E. nitida, E. bifida S.G. Smith and E. occulta S.G. Smith have little variation and are very distinct (S.G. Smith 2001).

7. Eleocharis elliptica Kunth
PLANTS perennial, 5--90 cm; rhizome moderately long, tough, 0.5–1.5 mm thick.
STEM subcylindric or slightly compressed, often with several prominent ridges or angles, 0.3–0.8 mm thick, to ca. 2X wider than thick.
LEAVES: Distal sheath persistent, firm, tip obtuse to subacute, generally all or some leaves of plant with tooth-like projection to 0.5 mm.
INFLORESCENCE: spikelet 3–8 x 2–3(–4) mm; scales10–30, 1.7–3 x 1–1.5 mm, 5–7 per mm of rachilla, tip rounded to obtuse (or acute), often shallowly notched or cut to 0.5 mm deep.
FLOWER: Perianth bristles 0 or rarely 1–3, to ½ of fruit length; anthers 0.8–1.7 mm; stigmas 3 or some 2 in same spikelet.
TUBERCLE generally much lower than wide, 0.1–0.25 x 0.25–0.45 mm.
FRUIT persistent after scales fall (often through the winter), trigonous or some lenticular in same spikelet, 0.7–1.2 x 0.6–0.9 mm, finely to coarsely rugulose at 10X with 12–20 horizontal ridges.
CHROMOSOME NUMBER: 2n = 38.
ECOLOGY: Rare in the West. Very wet calcareous seeps, fens.
ELEVATION: [0–1000 m]
DISTRIBUTION: N.W.T. and B. C. to Labrador, s to n Idaho, Montana, Tennessee and Virginia.
FLOWERING TIME: Late spring to summer.
NOTE: Eleocharis elliptica probably hybridizes with E. erythropoda, and with E. compressa var. compressa (to produce E. elliptica var. atrata). It is premature to formally recognize varieties in E. elliptica because of the complex variation within the E. tenuis complex.
SYNONYMS: Eleocharis capitata (L.) R. Br. var. borealis Svenson; E. compressa Sullivant var. atrata Svenson; E. compressa var. borealis (Svenson) Drapalik & Mohlenbrock; E. elliptica var. atrata (Svenson) S.G. Smith; E. tenuis (Willdenow) Schultes var. borealis (Svenson) B. Boivin; E. tenuis var. borealis (Svenson) Gleason

8. Eleocharis compressa Sullivant var. acutisquamata (Buckley) S. G. Smith
PLANTS: Perennial, to ca. 60 cm; rhizome short to moderately long, tough, ca. 2–3 mm thick.
STEM subcylindric to slightly compressed, less than 2 times wider than thick, often with prominent ridges, (0.2–)0.5–1 mm thick.
LEAVES: Distal sheath persistent, firm, tip obtuse, rarely all or some sheaths of plant with tooth-like projection to 0.1(0.5) mm.
INFLORESCENCE: Spikelet 4–12 x 2--4 mm; scales ca. 40–80, 2.5–3.5 x ca. 1.2 mm, 5–7 per mm of rachilla, tip acute to acuminate, some in spikelet bifid to shallowly notched or deeply cut (rarely all scales entire).
FLOWER: Perianth bristles 0 (or sometimes 1–3?), to shorter than fruit; stigmas 3 or some 2 in same spikelet.
TUBERCLE pyramidal, often depressed, sometimes rudimentary, 0.2—0.25 x 0.2–0.35 mm.
FRUIT trigonous, 0.9–1 x 0.6–0.7 mm, finely rugulose.
CHROMOSOME NUMBER: 2n = 24 (not published?).
ECOLOGY: Very local in B.C. [Wet to damp (or dry) prairies and prairie swales, calcareous seepages, small intermittent wetlands, ditches, pond margins, often on limestone substrates.]
ELEVATION [0–2300 m]
DISTRIBUTION: B.C.?; Saskatchewan and Manitoba to Texas and Illinois.
FLOWERING TIME: Spring to summer.
NOTE: Very similar to E. elliptica. Eleocharis compressa was included in the B.C. flora in FNA based on a single doubtfully identified specimen. Eleocharis compressa var. acutisquamata intergrades in central and eastern N.Am. with E. compressa var. compressa, which differs mainly in its distinctly compressed stems 2–5 times wider than thick. It seems likely that E. compressa is of hybrid origin from E. occulta S.G. Smith of Texas and Oklahoma and E. bifida of Tennessee and adjacent states, in both of which all of the spikelet scale tips are bifid, and one or more species such as E. erythropoda and (some populations of) E. elliptica, in which the scales are entire.
SYNONYM: Eleocharis acutisquamata Buckley

9. Eleocharis nitida Fernald
PLANTS: Perennial, 2–15 cm; rhizome moderately long, tough, 0.3–0.5 mm thick.
STEM cylindrical, 0.15–0.3 mm thick
LEAVES: Distal sheath persistent, firm, tip obtuse to acute, tooth absent.
INFLORESCENCE: Spikelet 1–4 x 1–2 mm; scales 5–30, 1–1.3 x 1 mm, 8 per mm of rachilla, tip rounded, entire.
FLOWER: Perianth bristles 0; anthers 0.3 mm; stigmas 3.
TUBERCLE much lower than wide, rudimentary to 0.15 x 0.15–0.3 mm.
FRUIT persistent after scales fall, trigonous, 0.6–0.7 x 0.5–0.6 mm, rugulose at 20--30X with 20 horizontal ridges.
CHROMOSOME NUMBER unknown.
ECOLOGY: Very local. Fresh bog pools, streams, disturbed places.
ELEVATION: [30–400 m]
DISTRIBUTION: Boreal: Alaska; Saskatchewan; Minnesota to Labrador and New Hampshire.
FLOWERING TIME: Summer.
NOTE: Eleocharis nitida closely resembles very small plants of E. elliptica.

C. Eleocharis rostellata group: Series Rostellatae S. Gonzalez & P.M. Peterson
Plants robust, perennial, mat-forming; some stems elongating and tips rooting; fruit smooth or nearly so, tubercle poorly differentiated from fruit.

10. Eleocharis rostellata (Torrey) Torrey
PLANTS perennial, 20--50 cm; rhizome hidden among stem bases, ascending, short, caudex-like, tough, hidden by stems, ca. 3 mm thick.
STEM compressed, 0.3–2 mm wide, generally with to 8 sharp ridges or sometimes nearly smooth, firm to hard, some arching over and tips rooting to form new plants.
LEAVES: Distal sheath persistent, firm, tip obtuse to subacute.
INFLORESCENCE: Spikelet 5–17 x 2.5–5; scales 20–40, 3.5–6 x 2–3 mm.
FLOWER: Perianth bristles to (0)4--6, ca. equaling fruit or tubercle; anthers 2–2.4 mm; stigmas 3 or some 2 in same spikelet.
TUBERCLE often merging with fruit or absent, pyramidal, to 0.5 x 0.3 mm.
FRUIT trigonous or some lenticular in same spikelet, 1.5–2.5 x 1-1.2 mm, smooth or finely rough, tip generally narrowed into a stout beak.
ECOLOGY: Uncommon but widespread. Fens, springs, hot springs, [coastal marshes].
ELEVATION: [minus 50 to 2400 m]
DISTRIBUTION: B.C. to Nova Scotia s to California and Florida; Mexico, West Indies.
FLOWERING TIME: [Late spring–summer].
SYNONYM: Scirpus rostellatus Torrey

D. Eleocharis quinqueflora group: Eleochnaris subg. Zinserlingia Egorova
Plants medium-sized, perennial, mat-forming; rhizomes weak, tips with enlarged buds or resting bulbs; tubercle poorly differentiated from fruit. This is a difficult circumboreal complex in need of a taxonomic revision. (Reference: S.G. Smith 2001).

11. Eleocharis suksdorfiana Beauverd
PLANTS perennial, 10–40 cm; rhizome moderately long, weak, 0.5–1.5 mm thick, tip with enlarged, ellipsoid, 10 x 2–5 mm bud; stem-tuft base not markedly swollen, with hard caudex, surface without 2-veined scales; bulbs unknown.
STEM erect, cylindric to compressed, to 2 X wider than thick, 0.5–1.2 mm wide.
LEAVES: Distal sheath persistent, firm, tip subtruncate to obtuse.
INFLORESCENCE: Spikelet (often absent) 5–10 x 2–4 mm; basal scale about ½ of spikelet length or shorter; scales 8–12, 3.5–5 x 2–2.5 mm.
FLOWER: Perianth bristles 6, equaling or exceeding tubercle; stigmas 3; anthers 1.6–3.5 mm.
TUBERCLE often merging with fruit, pyramidal, 0.4–0.5 x 0.3–0.5 mm.
FRUIT trigonous or rarely some lenticular in same spikelet, 2–2.7 x 0.7–1.3 mm, smooth or finely longitudinally ridged or reticulate, tip narrowed into a pale-colored, stout beak.
ECOLOGY: Probably rare. Wet meadows, fens, springs.
ELEVATION: [0--3400 m]
DISTRIBUTION: s B.C. to w Montana, s to California and Colorado.
NOTE: Herbarium specimens of E. suksdorfiana may be confused with E. rostellata, in which the culms, achenes and tubercles are very similar. Eleocharis suksdorfiana has long been treated as a synonym of E. pauciflora or E. quinqueflora, but my field observations in California and herbarium studies, including isotypes, show that these are clearly distinct species.
SYNONYMS: Eleocharis pauciflora (Lightfoot) Link var. suksdorfiana (Beauverd) Svenson; E. quinqueflora subsp. suksdorfiana (Beauverd) Hulten

12. Eleocharis quinqueflora (Hartmann) O. Schwarz
PLANTS: Perennial, 5–35 cm; rhizome moderately long, weak, 0.2–1 mm thick, tip often with ovoid bulb 3–11 x 1–5 mm; stem-tuft base generally markedly swollen, often with a bulb among stem bases, surface often with 2-veined scales (prophylls) and/or several bulbs at tips of very short rhizomes, hard caudex absent [or rarely present].
STEM subcylindric, 0.2–0.5(–1.2) mm thick.
LEAVES: Distal sheath persistent, firm, tip subtruncate to acute.
INFLORESCENCE: Spikelet often absent, 3–8 x 1.5–4 mm; basal scale greater than or equaling ½ of spikelet length, flower present or seldom absent; scales 3–10, 2.5–6 mm.
FLOWER: Perianth bristles 0 to 6(7?), rudimentary to ca. equaling fruit; anthers ca. 1.5–3 mm; stigmas 3.
TUBERCLE often merging with fruit, sometimes absent, pyramidal, 0.3–0.4 x 0.2–0.3 mm.
FRUIT trigonous, 1.6–2.3 x 0.7–1.3 mm, smooth or finely longitudinally ridged, tip often beak-like.
ECOLOGY: Uncommon. Wet meadows, fens, seeps, shores.
ELEVATION: [0–3600 m.]
DISTRIBUTION: Boreal and temperate Northern Hemisphere: Alaska to Greenland and Newfoundland, s to California, New Mexico, New Jersey; Eurasia.
FLOWERING TIME: [Spring to] summer.
NOTE: E. quinqueflora is very variable world-wide. The names Scirpus quinqueflorus and S. pauciflorus need typification; both were described from Europe. Some variants may deserve recognition as species or infraspecific taxa. California plants at lower elevations, especially in the Sacramento Valley, have many large bulbs but no fruit and often no spikelets; these intergrade with plants at elevations to 3000 m and outside of California to British Columbia, Montana and Arizona with smaller bulbs and often with fruit. My preliminary field observations in California suggest that bulbs are sometimes produced only where the soil is drying. Many California plants at elevations over 1700 m in the Sierra Nevada, Cascade Ranges (Mt. Lassen) and San Bernardino Co. differ consistently from all other North American plants in having culm-tuft bases with hard caudices; spikelets with only 3–4 flowers, the scales only 2.5–4 mm and dark chestnut-colored, and the basal scale without a flower.
SYNONYMS: Eleocharis pauciflora (Lightfoot) Link; E. pauciflora var. fernaldii Svenson; E. quinqueflora subsp. fernaldii (Svenson) Hulten; Scirpus pauciflorus Lightfoot; S. quinqueflorus Hartmann.

E. Eleocharis acicularis group: Subg. Scirpidium (Nees) Kukkonen
Plants very small (but stems often long when submerged), our species perennial and mat-forming, often submerged aquatic; rhizome internodes long; spikelet basal scale with a flower; fruit with longitudinal ridges and numerous fine cross-bars.

13. Eleocharis acicularis (L.) Roemer & Schultes
COMMON NAME: Needle Spike-Rush
PLANTS perennial, 1–60 cm, often forming mats; rhizome long, weak, to 0.5 mm thick.
STEM subcylindric, often with 3 or more angles or ridges, 0.2–0.5 mm thick.
LEAVES: Distal sheath delicate, often disintegrating, tip sometimes inflated.
INFLORESCENCE: Spikelet 2–8 x 1–2 mm, often absent on submerged plants; basal scale with flower; scales 4--25, 1.5– 2.5(--3.5) x 1–1.5, mm, tip blunt to acute.
FLOWER: Perianth bristles 0(–4), to equaling fruit; anthers 0.7–1.5 mm; stigmas 3.
FRUIT often whitish, trigonous to sub-circular in x-section, with 8–12 longitudinal ridges and 30–60 cross-bars, 0.7–1.1 x 0.35–0.6 mm.
CHROMOSOME NUMBER: 2n = 20.
ECOLOGY: Common, widespread. Fresh wet soil to deeply submerged;
ELEVATION: [0--3300 m]
DISTRIBUTION: Boreal and temperate N. Am., Mexico, Central Am., Equador, Eurasia, Australia (introduced?).
FLOWERING TIME: [Late spring].to fall.
NOTES: The closely related E. bella, which is generally tufted and without rhizomes, has scales only 1–1.5 mm and achenes only 0.55–0.75 mm with about 20–30 cross-bars, is known from western Washington to northwestern Montana and should be sought in B.C. Eleocharis acicularis without fruit is easily confused with E. parvula, in which the spikelet basal scale is without a flower and the rhizome tip often bears a tuber.
The following varieties may deserve recognition:
1) E. acicularis var. acicularis: Stems often 3--4-angled, to 60 cm, base not corm-like; fruit 2 X longer than wide. Widespread in N. Am. and Eurasia.
2) E. acicularis var. occidentalis Svenson: Stems often 5--8-ridged, to 6 cm, base corm-like; fruit less than 2X longer than wide. California to Washington, Wyoming, New Mexico.
3) E. acicularis var. gracilescens Svenson: Stems often 5–12-ridged, base not corm-like, to 60 cm; spikelet to 8 mm, scales to 3.5 mm; fruit less than 2 X longer than wide. California to Oregon, Tennessee.
4) E. acicularis var. submersa Svenson: Aquatic form which in deep water may form large vegetative mats and may closely resemble Schoenoplectus subterminalis (Torrey) Sojak. Widespread in N. Am. and Eurasia.

F. Eleocharis parvula group: Section Parvulae Egorova
Plants very small, perennial, mat-forming; rhizome weak, short, tip often with tuber; fruit smooth or rugulose, tubercle poorly differentiated from fruit; spikelet proximal scale without a flower.

14. Eleocharis parvula (Roemer & Schultes) Link ex Bluff
PLANTS perennial, 2–9 cm; rhizome weak, to 0.2–0.3 mm thick, tip often with oblong and often markedly curved tuber 2–2.5(–5) x 0.5–1 mm.
STEM cylindric, 0.2–0.5 mm thick.
LEAVES: distal sheath often disintegrating, delicate, tip rounded.
INFLORESCENCE: Spikelet 2–4 x 1–2 mm; scales 6–10, 1.4–2.7 mm.
FLOWER: Perianth bristles 6, ca. ½ of- to equaling fruit length; anthers 0.7–1.2 mm; stigmas 3, rarely some 2 in same spikelet.
TUBERCLE often poorly differentiated from fruit or rudimentary, 0.1–0.2 x 0.15 mm.
FRUIT trigonous, 0.9–1.2 x 0.6–0.8 mm, smooth.
CHROMOSOME NUMBER: [2n=10. Europe].
ECOLOGY: Very local in B.C. Brackish wet soil, coastal [rarely inland].
ELEVATION: 0 [–600] m.
DISTRIBUTION: B.C. to California; Kansas, Michigan and Labrador to Louisiana and Florida; Mexico, Central America, Eurasia.
FLOWERING TIME: [Late winter to fall?].
SYNONYMS: Eleocharis pygmaea Torrey; Scirpus nanus Sprengel; S. parvulus Roemer & Schultes
NOTES: The closely related E. coloradoensis (Britton) Gillyl, in which the perianth bristles are rudimentary or absent and the tubers are broadly oblong to orbicular and not markedly curved, is not known from B.C. but should be sought in inland localities. Plants without fruits or tubers are easily confused with E. acicularis, in which the spikelets have basal scales with flowers.

G. Eleocharis atropurpurea group: Series Maculosae Svenson
Plants are small in all dimensions, with or without rhizomes; stigmas 2; fruit lenticular, smooth; tubercle not appressed to achene.

15. Eleocharis atropurpurea (Retzius) J. Presl & C. Presl
PLANTS annual?, tufted, 2–12(–19) cm; rhizome absent; all plant parts small.
STEM subcylindric, to 0.3 mm thick.
LEAVES: Distal sheath persistent, firm, tip acute.
INFLORESCENCE: Spikelet 2–6(–8) x 1–2.5 mm; basal scale with or without flower; scales to 100, 0.6–1.3 mm, 0.6–1.3 x 0.3–0.7, 15–19 per mm of rachilla, tip rounded to acute.
FLOWER: Perianth bristles (0)4(–6), whitish, to ½ of fruit length; anthers to ca. 0.5 mm; stigmas 2.
TUBERCLE umbonate to subconic, 0.1–0.2 x 0.1–0.2 mm.
FRUIT black when ripe, lenticular, 0.3–0.5 x 0.3–0.4 mm, smooth.
CHROMOSOME NUMBER: 2n = 20.
ECOLOGY: Rare in B.C. Fresh, wet, bare soil;
ELEVATION: [0--1800 m]
DISTRIBUTION: B.C. and Washington; California; Michigan; Nebraska and Iowa to New Mexico Florida; world-wide, distribution scattered.
FLOWERING TIME: Summer to fall.
SYNONYM: Scirpus atropurpureus Retzius
REFERENCE: F.J. Menapace (2002).

H. Eleocharis ovata group: Series Ovatae Svenson
Plants small to medium-sized, tufted annuals without rhizomes; distal leaf sheath persistent, firm; fruit brown when ripe, smooth, tubercle completely adherent to achene.

16. Eleocharis engelmannii Steudel var. engelmannii
PLANTS: Annual, tufted, 2–40 cm; rhizome absent.
STEM cylindric, 0.5–2 mm thick.
LEAVES: Distal sheath persistent, firm, tip obtuse to acute, with tooth-like projection to 0.3 mm.
INFLORESCENCE: Spikelet 5–10(--20) x 2—3(--4) mm; scales 25–100+, 2–2.5 x 1–1.3 mm.
FLOWER: Perianth bristles 5–8, equaling fruit to slightly exceeding tubercle; anthers 0.3–1 mm, stigmas 2--3.
TUBERCLE completely adherent to fruit, greatly dorsoventrally compressed, 1/10–2/5 as high as wide and 9/10 as wide as fruit, 1/4 or less as high as fruit.
FRUIT lenticular or some trigonous, smooth, 0.9–1.1[–1.5] x 0.7–1.1 mm, tip broadly truncate;
CHROMOSOME NUMBER: 2n = 10.
ECOLOGY: Very local in B.C. Fresh wet bare soil.
ELEVATION: [30–2400 m]
DISTRIBUTION: Temperate N. Am. except far Southeast.
FLOWERING TIME: Spring to fall.
SYNONYM: Eleocharis monticola (Fernald) Svenson
NOTES: Although varieties of E. engelmannii were not recognized in FNA, they seem to have distinct distributions and should be considered for recognition.
The following variety is not known from B.C. but is widespread in N.Am.:
Eleocharis engelmannii var. detonsa A. Gray in Patterson: Perianth bristles rudimentary or absent. Synonyms: E. ovata (Roth) Roemer & Schultes var. detonsa (A.Gray) Mohlenbrock; E. engelmannii forma detonsa (A. Gray) Svenson; E. monticola var. leviseta Fernald

17. Eleocharis obtusa (Wildenow) Schultes
PLANTS: Annual, tufted, 3–50 cm; rhizome absent.
STEM cylindric, 0.2–2 mm thick.
LEAVES: Distal sheath persistent, firm, tip obtuse to acute, with tooth-like projection to 0.3 mm.
INFLORESCENCE: Spikelet (2–)5–13 x (2–)3--4 mm; scales 15–150+, 1.5–2.5 x 1–1.5 mm, tip broadly rounded.
FLOWER: Perianth bristles (5–)6--7, very rarely 0, slightly- to generally greatly exceeding tubercle; anthers 0.3–0.6 mm; stigmas 2--3.
TUBERCLE completely adherent to fruit, dorsoventrally flat, 1/3–1/2 as high as wide and 2/3–9/10 as wide as fruit, 1/3 or more as high as fruit.
FRUIT lenticular or some trigonous, smooth, 0.9–1.3 x 0.7–0.9 mm.
CHROMOSOME NUMBER: 2n = 10.
ECOLOGY: Very local in B.C. Fresh shores, marshes, seepages, disturbed places.
ELEVATION: [10–1600 m]
DISTRIBUTION: s B.C. to California; Idaho, Wyoming, Colorado e to P.E.I., s to Texas and Florida; Hawaii.
FLOWERING TIME: Late spring to fall.
NOTE: Small plants are easily confused with E. ovata. Robust plants with distinct caudex, floral scales 2.5 mm and achenes 1.2–1.3 mm may deserve taxonomic recognition as E. obtusa var. gigantea Fernald, type from the B.C.-Washington border.
SYNONYMS: Eleocharis obtusa var. ellipsoidalis Fernald; E. obtusa var. gigantea Fernald; E. obtusa var. jejuna Fernald; E. obtusa var. peasei Svenson; Scirpus obtusus Wildenow

18. Eleocharis ovata (Roth) Roemer & Schultes
PLANTS: Annual, tufted, 2–35 cm; rhizome absent.
STEM cylindric, 0.3–1 mm thick.
LEAVES: Distal sheath persistent, firm, tip obtuse to acute, with tooth-like projection to 0.2 mm.
INFLORESCENCE: Spikelet 2–8 x 2--4 mm; scales 25–100+, 1.5–2.5 x ca. 1 mm, tip rounded to subacute.
FLOWER: Perianth bristles (5–)6--7, exceeding tubercle; anthers ca. 0.3 mm; stigmas 2--3.
TUBERCLE completely adherent to fruit, dorsoventrally flat, 3/5 to as high as wide and 1/3--2/3 as wide as fruit, 1/3 or more as high as fruit.
FRUIT lenticular or some trigonous, smooth, 0.7–1 x 0.6–0.9 mm, tip rounded.
CHROMOSOME NUMBER 2n = 10.
ECOLOGY: Very local in B.C. [Fresh, often drying shores, lake and stream beds, bogs, tidal estuaries, disturbed places.]
ELEVATION: [30–2400 m?].
DISTRIBUTION: B.C. and Alberta to California; Arizona; Ontario to Newfoundland s to Oklahoma and North Carolina; Europe.
FLOWERING TIME: Summer to fall.
NOTE: Easily confused with small plants of E. obtusa.
SYNONYMS: Eleocharis obtusa (Wildenow) Schultes var. ovata (Roth) Drapalik & Mohlenbrock; E. ovata var. heuseri Uetrichtz; Scirpus ovatus Roth

ACKNOWLEDGEMENTS

I thank Theodore S. "Ted" Cochrane, Mark Wetter, Hugh H. Iltis and Kenneth Systma of the University of Wisconsin Department of Botany for providing essential logistic, technical and moral support; Ted for critically reading this paper; the Department of Biological Sciences at University of Wisconsin-Whitewater for logistic support; S. Frank Lomer for sending me duplicates of his collections and his stimulating correspondence; and Adolf Ceska for inviting me to submit this paper and his moral support in my endeavors over several years.

REFERENCES

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