Andropogon gerardii — big bluestem

Characteristics

• Flowers

  Anther length

  2.5–4.5 mm

  Anther number

  3

  Awn on glume

  the glume has no awn

  Bristles below spikelets

  no

  Floret lower bract texture

  the lemma is thin and flexible

  Floret number

  1

  Floret types within spikelet

  there are at least two distinct forms of florets within one spikelet

  Glume awn length

  0 mm

  Glume relative length

  one or both glumes are as long or longer than all of the florets

  Glume shape

  the glume is flat or curved in cross-section

  Glume veins

  • 1
  • 3
  • 5
  • 7 or more

  Glumes per spikelet

  2

  Inflorescence arrangement

  the plant has two types of spikelets with different reproductive structures

  Inflorescence axis orientation

  the inflorescence axis is straight

  Inflorescence branches

  the flowers are attached to branches rather than to the main axis of the inflorescence

  Inflorescence crowding

  NA

  Inflorescence length

  30–150 mm

  Inflorescence type (general)

  the spikelets are borne on stalks or on branches

  Inflorescence type (specific)

  the inflorescence has pairs (or trios) of spikelets, but with one always either missing a stalk or on a shorter stalk than the other

  Inforescence position

  the spikelets are mainly carried at the end of the stem

  Lemma awn base

  • NA
  • the awn is attached right at the tip of the lemma

  Lemma awn coiled

  the lemma awn is coiled at least one half turn

  Lemma awn length

  0–25 mm

  Lemma awn number

  • the lemma has no awn
  • the lemma has one awn on it

  Lemma awn orientation

  the awn of the lemma on dried or older plants is curved or bent outwards

  Lemma base hairs

  the lemma has hairs at the base

  Lemma cross-section

  the lemma is flat or rounded if you cut across the midpoint

  Lemma hairs

  the lemma is hairless between the veins

  Lemma surface

  the surface of the lemma is relatively smooth (not counting any longitudinal veins or hairs)

  Lemma tip

  the lemma tip is split into two or more points

  Lower glume length

  Up to 11 mm

  Lower glume relative length

  the lower glume is nearly as long, or as long as, the upper glume

  One or more florets

  there is one floret per spikelet

  Reproductive system

  some flowers on the plant have both carpels and stamens, while other flowers have only one type of reproductive organ (polygamous)

  Spikelet axis length

  0 mm

  Spikelet axis tip

  there is no extension of the spikelet axis beyond the tip of the spikelet

  Spikelet disintegration

  the spikelet breaks off below the glumes

  Spikelet length

  5–11 mm

  Spikelet number per node

  0

  Spikelet pedicel

  • the spikelets do not have pedicels
  • the spikelets have pedicels

  Spikelet pedicel length

  At least 0 mm

  Spikelet position

  NA

  Spikelets spiny

  the spikelets do not appear spiny

  Tip of glume

  the tip of the glume is not divided (though it may have an awn on it)

  Upper glume length

  Up to 11 mm

  Upper glume relative length

  the upper glume is more than one half as long as the lowest lemma

  Upper glume shape

  the upper glume is widest at or below the middle

• Growth form

  Horizontal rooting stem

  no

  Lifespan

  the plant lives more than two years

  Rhizomes

  yes

  Roots

  the plant has rhizomes (horizontal underground stem with roots growing from it)

• Leaves

  Basal leaves

  the plant has few or no leaves coming from the base of the flowering stem

  Leaf auricles

  the leaves do not have auricles

  Leaf basal lobe hairy

  NA

  Leaf blade cross-section

  the leaf blade is more or less flat in cross-section, or slightly folded or rolled inwards

  Leaf blade hairs

  the leaf blade is hairy

  Leaf blade length

  5–50 cm

  Leaf blade texture

  the leaf blade is rough and sandpapery

  Leaf blade width

  2–10 mm

  Leaf ligule length

  0.4–2.5 mm

  Leaf ligule type

  the leaf ligule is in the form of a membrane

  Leaf margin glands

  there are no glands along the edges of the leaf blade

  Leaf sheath closed around stem

  the margins of the leaf sheath are overlapping and not fused together except in the basal half (or less)

  Leaf sheath hair type

  • there are hairs on the surface of the leaf sheath, but the hairs do not have blisters at their bases
  • there are no hairs on the surface of the leaf sheath

  Leaf sheath hairs

  • there are hairs on the surface of the leaf sheath
  • there are no hairs on the surface of the leaf sheath

• Place

  Habitat

  • terrestrial
  • wetlands

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont

  Specific habitat

  • cliffs, balds, or ledges
  • grasslands
  • man-made or disturbed habitats
  • meadows or fields
  • ridges or ledges
  • river or stream floodplains
  • shores of rivers or lakes
  • shrublands or thickets
  • woodlands

• Stem, shoot, branch

  Hairs at nodes

  the stem nodes are hairless or they have very sparse hairs

  Plant height

  100–300 cm

  Stem hairs

  the stem is nearly to completely hairless

  Stem orientation

  the stems are upright

  Stem spacing

  the stems grow close together in compact clusters or tufts

Wetland status

Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)

In New England

From Flora Novae Angliae dichotomous key