Eleocharis ovata

Ovate Spike Rush

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Flora, fauna, earth, and sky...
The natural history of the northwoods

Name:

• Eleocharis, from the Greek, `eleios (heleios) , "of the marsh or meadow", and caris (charis) , "joy; grace; kindness; beauty", sometimes a reference to a specific plant.
• ovata, from the Latin, "oval"
• Common Name, from the shape of the flowering spike
• Other common names include: bahnièka vajcovitá (Slovak)

Taxonomy:

• Kingdom Plantae, the Plants
  • Division Magnoliophyta, the Angiosperms (flowering plants)
    • Class Liliopsida, the Monocotyledons
    • Subclass Commelinidae
      • Order Cyperales
        • Family Cyperaceae, the Sedges
          • Genus Eleocharis, the Spike Rushes, over 100 difficult-to-distinguish species worldwide.
• Taxonomic Serial Number: 40061
• Also known as Eleocharis annua, Eleocharis obtusa var. heuseri, Eleocharis obtusa var. ovata, Scirpus ovatus

Description:

• A tufted annual herb
• Leaves reduced to basal sheaths, the sheaths red, brown, or straw-colored.
• Stems upright, unbranched, rather slender, inconspicuously 3-angled, smooth, up to 18" tall, each bearing a terminal spike.
• Roots fibrous, to 6" deep
• Flowers crowded into a terminal spike, the spike ovoid, pointed at the tip, up to ½" long and ¼" thick; scales appressed, narrowly ovate to oblong, rounded at the tip, sometimes purplish. Flowering August-October
  • Sepals absent
  • Petals absent
  • Stamens 3
  • Pistils 2 styles
  • Ovary superior (within blossom)
• Fruit an obovoid achene, flattened laterally, yellow to deep brown, smooth, about 1/20" long, with a terminal tubercle; tubercle 1/2-2/3 the width of the achene, sometimes 2- or 3-parted at the tip; bristles longer than the achene, or lacking.

Identification:

• A leaf-less, grass-like waterside plant
• Distinguished by its ovoid spike that is pointed at the tip and the tubercle of the achene 1/2-2/3 the width of the achene.

Distribution:

• Circumboreal; Pacific Northwest across Northern Plains and Great Lakes states to New England.

Habitat:

• Edges of ponds and moist soils; shallow waters Wet ground.

Associates:

• Trees: Tamarack (Larix laricina), Black Spruce (Picea mariana)
• Shrubs: Bog Birch (Betula pumila), Leatherleaf (Chamaedaphne calyculata), Sweet Gale (Myrica gale)
• Herbs: Blue Flag Iris (Iris versicolor), Cattails (Typha spp)
• Birds: achenes eaten by waterfowl.

History:

Uses:

Reproduction:

• By seed
• Flowers August-October

Propagation:

• By seed

Cultivation:

• Hardy to USDA Zone 2 (average minimum annual temperature -50ºF)
• Cultural Requirements
• Sun full; shade intolerant
• Soil pH 4.6-6.8
• Water use medium
• Fertilization unnecessary
• Minimum frost-free days - 90
• Size 6"-12"W x 12"-18"H
• Growth rate moderate

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