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beautiful spikerush, delicate spikerush, pretty spikerush

dwarf spike-rush

Habit Plants annual, rarely perennial, usually densely tufted; rhizomes rarely evident, 0.2–0.3 mm thick, internodes 1–5 mm, scales not evident.
Culms

often ascending or spreading, 4-angled or sometimes terete, sometimes sulcate, 1–7 cm × 0.2–0.3 mm, soft to firm.

Leaves

sheaths stramineous, distal sheaths often splitting abaxially, slightly inflated distally, oblique, apex acute.

Spikelets

ovoid, 1.5–4 × 0.8–2 mm, apex acute;

floral scales 4–15, 8 per mm of rachilla, colorless or reddish brown, midrib region green, ovate-lanceolate, not folded lengthwise, 1–1.5 × 0.5–0.7 mm, mibrib obscure to somewhat keeled, apex narrowly acute to acuminate, slightly recurved.

3–6 × 1–1.5 mm;

proximal scale 1/2 or less of spikelet length;

floral scales 6–25 per spikelet, mostly bright orange-brown, sometimes stramineous, 1.7–2.5 mm, apex subacute.

Flowers

perianth bristles absent;

anthers 0.3–0.5 mm.

perianth bristles mostly absent or rudimentary, occasionally to 5, 1/2 of achene length, very unequal;

anthers 0.6–0.9 mm.

Achenes

with angles and longitudinal ridges ca. 6–10, rather prominent, broadly ovoid, less than 2 times longer then wide, (0.55–)0.65–0.75 × 0.3–0.4 mm, apex blunt, trabeculae distinct, 20–30.

medium to dark brown, obovoid to obpyriform, thickly trigonous, rarely some biconvex, angles distinct to prominent, faces convex or some plane, 0.75–1.1 × 0.55–0.7 mm, apex narrowly truncate or tapered into tubercle, rugulose at 10X to finely rough at 30X.

Tubercles

grayish, mostly appressed, pyramidal, often depressed, 0.1–0.2 × 0.1–0.25 mm.

0.05–0.2 × 0.15 mm.

Tubers

terminating rhizomes, 2.5–4 × 0.7–1.5 mm, body (apart from apical bud) broadly oblong to orbicular, not markedly curved.

Eleocharis bella

Eleocharis coloradoensis

Phenology Fruiting spring–summer. Fruiting summer–fall (north), spring–fall (far south).
Habitat Bare, often drying soil of stream alluvium, lake margins, wet meadows Fresh or brackish drying lake and pond margins, stream beds, flood plains, vernal pools, irrigation ditches, tidal wetlands
Elevation 200–2900 m (700–9500 ft) 0–2100 m (0–6900 ft)
Distribution
from FNA
AZ; CA; ID; MT; NM; NV; OR; WA; Mexico (Chihuahua)
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CA; CO; IA; ID; KS; LA; MN; MO; MS; ND; NM; NV; OK; OR; SD; TX; UT; MB; SK; Mexico
Discussion

Eleocharis bella and E. acicularis seem to be amply distinct; putative hybrids are unknown. The occasional plants of E. bella with evident rhizomes, which include the type, are otherwise identical to plants apparently without rhizomes. Eleocharis bella is very similar to E. cancellata. There is an Illinois collection from Peoria in 1901, from the alluvial banks of the Illinois River.

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

Most authors, except C. L. Gilly (1941), H. L. Mason (1957), and R. R. Yeo (1980), have included Eleocharis coloradoensis in E. parvula or E. parvula var. anachaeta. In typical E. coloradoensis, which occurs from Saskatchewan south to Kansas and in California to 2100 m elevation, the achenes are usually distinctly rugulose or rough, often pitted-cellular, their apices usually truncate, and the tubercles are usually brown, often rudimentary, clearly distinct from the achene, and apparently partly sunken into the achene summit. Some plants from the southern Great Plains to the Mexican border, including the type of E. parvula var. anachaeta from Louisiana, may deserve taxonomic recognition. They differ from typical E. coloradoensis in having nearly smooth achenes with the apex tapered to a tubercle that is difficult to distinguish from the achene. C. L. Gilly (1941) separated these plants as E. membranacea (Buckley) Gilly; application of that name is doubtful because achenes are lacking from the type. R. R. Yeo (1980) studied the life-history of E. coloradoensis in the Sacramento Valley, California, and showed that it can be used to control several aquatic weeds in irrigation canals. The n = 4 count reported from Kansas under E. parvula var. anachaeta (Anonymous 1964) and on voucher specimens at GH and UC, is probably erroneous; the label on a duplicate voucher specimen at NDA includes the information “n = 3 II’s + a chain of IV” (i.e., n = 5). The record from Washington is somewhat doubtful because the specimen lacks achenes. Literature reports of E. parvula from Illinois and Tennessee may refer to E. coloradoensis; I have not seen specimens.

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

Source FNA vol. 23, p. 110. FNA vol. 23, p. 106.
Parent taxa Cyperaceae > Eleocharis > subg. Scirpidium Cyperaceae > Eleocharis > subg. Eleocharis > sect. Parvulae
Sibling taxa
E. acicularis, E. aestuum, E. albida, E. ambigens, E. atropurpurea, E. baldwinii, 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
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. 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 E. acicularis var. bella, E. acicularis var. minima Scirpus coloradoensis, E. parvula var. anachaeta
Name authority (Piper) Svenson: Rhodora 31: 201. (1929) (Britton) Gilly: Amer. Midl. Naturalist 26: 66. (1941)
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