The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

black sand spikerush, broad fruit spikerush

Baldwin's spike-rush

Habit Plants perennial, forming dense clumps, often stoloniferous. Plants annual(?), often mat-forming, often stoloniferous, sometimes entirely vegetative; rhizomes absent.
Rhizomes

present, caudexlike, mostly concealed by crowded culms, vertical or ascending, 2 mm thick;

internodes very short, scales disintegrating to fibers, 4 mm, papery.

Culms

erect to ascending or arching, acutely quadrangular, deeply sulcate, 7–50 cm × 0.3–0.5 mm, smooth, firm.

often arching, sometimes spotted or streaked red-brown, quadrangular or broadly elliptic, sulcate or not, 0.5–25(–30) cm × 0.1–0.4 mm, soft.

Leaves

distal leaf sheaths persistent, proximally brown or reddish, distally stramineous to green, thickly membranous, apex acute or subacute.

distal leaf sheaths persistent or disintegrating, stramineous, green, red-brown, or spotted or streaked red-brown, membranous, translucent, apex obtuse or acute.

Spikelets

basal spikelets absent; often proliferous, ovoid, terete, 3–10 × 2–3 mm, apex acute;

proximal scale empty, amplexicaulous, similar to floral scales;

subproximal scale with a flower;

floral scales spiraled, 8–15, 4 per mm of rachilla, orange-brown, midrib region broadly stramineous or like flanks, ovate, 2–3 × 1.2–2 mm, membranous, midrib evident to prominent, apex acute (to rounded).

basal spikelets usually present, pistillate; often proliferous, ovoid, ellipsoid, or linear, clearly laterally compressed, 2.3–6.9 × 0.5–2 mm, apex acute, proximal scale empty, amplexicaulous, similar to floral scales (midribs sometimes more prominent and sometimes slightly prolonged beyond lamina);

subproximal scale with a flower;

floral scales clearly distichous, 3–9, 3–4 per mm of rachilla, yellowish, pale brown, or red-brown, spotted, streaked, or mottled red-brown, narrowly ovate to oblong, (1.5–)2–5 × 0.4–0.6(–1.2) mm, membranous, apex rounded, obtuse or rarely acute, midribs keeled.

Flowers

perianth bristles 6 or fewer, stramineous, unequal, some or most equaling achene, spinules obscure, sparse, retrorse, sharply acute.

perianth bristles 3–7, incurved, colorless, white, or red-brown, shorter than or equaling achene;

spinules sparse, retrorse, sharply acute;

stamens 3;

anthers 1.4–2.2 mm;

styles 3-fid.

Stamens

3;

anthers 1.2–1.5 mm.

Styles

3-fid.

Achenes

stramineous, broadly obpyriform, equilaterally trigonous, angles evident, blunt, 0.9–1.1 × 0.7–0.9 mm, apex nearly truncate, smooth or obscurely papillose or rugulose at 20X.

whitish or greenish, spotted dark green, obovoid, trigonous, angles prominent, 0.6–0.9 × 0.4–0.6 mm, apex constricted proximal to tubercle, smooth to finely cancellate at 10–20X.

Tubercles

stramineous, pyramidal, trigonous, usually acute, proximally trilobed, the lobes decurrent on achene, 0.5–0.9 × 0.7–0.9 mm.

pale to red-brown, pyramidal, trigonous, 0.2–0.3(–0.4) × 0.2–0.5 mm.

Eleocharis pachycarpa

Eleocharis baldwinii

Phenology Fruiting late spring–summer. Fruiting early spring–winter.
Habitat Fresh shores, streambeds, groundwater seeps Freshwater to moist terrestrial sites, pine savannas, cypress ponds, lakeshores
Elevation 100–1400 m (300–4600 ft) 0–60 m (0–200 ft)
Distribution
from FNA
CA; NV; South America (Argentina, Chile) [Introduced in North America; introduced in Australia]
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; FL; GA; LA; MS; NC; SC; TX
[WildflowerSearch map]
[BONAP county map]
Discussion

H. K. Svenson (1957) placed Eleocharis pachycarpa in ser. Sulcatae Svenson. Contrary to his statement that perianth bristles are often lacking, they are present in all of the specimens we have seen. Superficially similar to E. bolanderi, from which it may readily be distinguished by its oblique leaf sheath summits, 4-angled culms, pyramidal tubercles, and often proliferating spikelets. The earliest North American specimen we have seen was collected in 1919 in Tuolumne County, California.

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

Coarse plants of Eleocharis baldwinii usually bear more achenes per spikelet, dark colored achenes, culms gray-green when dried, and yellowish sheaths. Finer plants often bear few achenes per spikelet, whitish achenes, culms that are mid green when dried, and reddish sheaths. Achene color may relate to maturity, with darker achenes being fully mature. Although these variants appear to intergrade, they may be recognizable taxonomically. The longer floral scales in the spikelet are usually 3.5– 5 mm.

We have not seen vouchers to verify the report of Eleocharis baldwinii from Virginia.

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

Source FNA vol. 23, p. 91. FNA vol. 23, p. 98.
Parent taxa Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Tenuissimae Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Tenuissimae
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. palustris, E. parishii, E. parvula, E. quadrangulata, E. quinqueflora, 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. 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. tenuis, E. torticulmis, E. tortilis, E. tricostata, E. tuberculosa, E. uniglumis, E. vivipara, E. wolfii
Synonyms Chaetocyperus baldwinii
Name authority E. Desvaux: in C. Gay, Fl. Chil. 6: 174. (1853) (Torrey) Chapman: Fl. South. U.S., 519. (1860)
Web links