Angiosperms: Monocotyledons

Cyperaceae
Sedge Family

• Notes:

  The sedge family is similar to the grass family with its reduced flowers and linear leaves. The family includes bulrushes, spike rushes, and nut grasses in addition to sedges. Only sedges (Carex) are included in this book. Sedges have one bract below each floret. The female florets have a unique structure, a peri-gynium, which is a membranous cylinder enclosing the pistil with its two or three styles projecting out. Male flowers have three stamens. Florets are arranged into spikes with male and female flowers segregated in one of three ways: separate spikes with the male spike taller than the female spikes, male and female flowers in the same spike with the male flowers at the base and the female flowers above, or the reverse with female flowers below male flowers in the same spike. Vegetatively sedges have leaves divided into sheath and blade as in the grasses. However, the sheath grows closed into a cylinder surrounding the stem, and leaves grow out from the stem in three rows up the stem rather than two rows as in the grasses.

  The following five sedges represent more than fifty sedge species that might be found on Iowa’s prairies according to Eilers and Roosa’s The Vascular Plants of Iowa. Positive identification of the sedges is based upon many technical characteristics and requires the use of a good hand lens or a low-power microscope. If you are interested in studying the group further, consult one of the manuals listed in the bibliography.

  The following key can be used to identify the five species treated here:
  If the spikes are elongate to 1” long
  Carex lasiocarpa
  If the spikes are roundish and the florets diverge, producing a bristly ball
  and the leaf sheaths are loose and mottled or green-striped
  Carex gravida
  and the leaf sheaths are tight and not mottled or green-striped
  Carex muhlenbergii
  and the florets are appressed together and the leaf blades are 1/8” wide
  Carex brevior
  and the leaf blades are 1/16” wide
  Carex bicknellii

• Bibliography from Biodiversity Heritage Library