Juncus biflorus — large grass-leaved rush

Characteristics

• Flowers

  Anther color (dry)

  the anthers range in color from white to tan or yellow to yellow-brown

  Anther length

  0.5–1.3 mm

  Floral bristle color

  NA

  Floral bristle number

  • 0
  • NA

  Floral bristle relative length

  NA

  Floral bristles

  NA

  Floral scale hairs

  NA

  Floral scale length

  0 mm

  Floral scale nerves

  NA

  Flower number per cluster

  • 5-20
  • more than 20

  Inflorescence bract angle

  the bracts are vertical or angled only slightly outwards

  Inflorescence bract number

  there are two to five bracts per inflorescence

  Inflorescence bract position (Sparganium)

  NA

  Inflorescence bracts

  there are at least two bracts, and they are either flat or folded or rolled in at the edges

  Inflorescence branching

  the inflorescence is branched

  Inflorescence crowding

  the inflorescence is at least somewhat spread out, with at least one branch coming from the main stem

  Inflorescence position

  the inflorescence is at the tip of the plant

  Inflorescence shape

  the aggregations within the inflorescence are roughly circular (not flattened) in cross-section

  Inflorescence type

  there are two or more flowers, spikes or flower clusters on a branched inflorescence

  Perianth composition

  the perianth is green or brown, with six sepal-like parts, and a leafy texture

  Stamen length

  1.4–3.7 mm

  Stamen number

  3

  Stigma number

  3

  floral bristle barbs

  NA

• Fruits or seeds

  Achene beak length

  0 mm

  Achene surface texture

  NA

  Achene tubercle relative width

  NA

  Achene tubercle width

  0 mm

  Capsule relative length

  • the capsule is about equal to the perianth
  • the capsule is longer thant he perianth
  • the capsule is shorter than the perianth

  Fruit cross-section

  the fruit is triangular to terete (circular) in cross-section

  Fruit length

  1.8–2.9 mm

  Fruit type (general)

  the fruit is a capsule, with at least three seeds in it

  Fruit type (specific)

  the fruit is a capsule (splits along two or more seams, apical teeth or pores when dry, to release two or more seeds)

  Locules in capsule

  the capsule has three locules

  Seed length

  0.4–0.7 mm

  Seed tail relative length

  0.4–0.7 mm

  Seed tails

  there is no tail on the seeds

  Tubercle height

  0 mm

• Growth form

  Lifespan

  the plant lives more than two years

  Underground organs

  • the plant has a rhizome (a horizontal underground stem with roots growing from it)
  • there are only slender roots on the plant

• Leaves

  Auricle length

  0.5–1.5 mm

  Auricle texture

  the auricles are weak, papery and translucent

  Auricles

  the leaf sheath has auricles on it

  Leaf blade cross-section

  the leaf blade is flat or rolled in at the edges

  Leaf blade length

  100–300 mm

  Leaf blade width

  1–6 mm

  Leaf form

  all the leaves hold their form out of water

  Leaf position on plant

  • some leaf attachment points are above the midpoint of the stem
  • the attachment points of all the leaves are at or near the base of the plant

  Leaf septa

  the leaf blades do not have transverse septa

  Leaf sheath hairs

  the leaf sheathes are without hairs

  Pedicel length (Typha)

  0 mm

  Stem leaf blade ligules

  there are no ligules at the leaf blade bases

  Stem leaf blades

  there are fully-developed leaves with leaf blades on the main stem

• Place

  Habitat

  wetlands

  New England state

  Massachusetts

  Specific habitat

  shores of rivers or lakes

• Stem, shoot, branch

  Plant height

  27.2–100.7 cm

  Stem shape in cross-section

  the stem is round or oval in cross-section

  Stem texture near tip

  the stem feels smooth near the tip

Wetland status

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

In New England

From Flora Novae Angliae dichotomous key