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• Dichotomous Key
• Poaceae
• Poaceae Group 7
• Piptatherum
• Piptatherum racemosum

Piptatherum racemosum — black-seeded mountain-rice grass

Facts

Black-seeded mountain-rice grass is a native grass of moist or dry-mesic forests where the bedrock is neutral to basic.

Habitat

Forests, ridges or ledges

Characteristics

• Flowers

  Anther length

  3.5–5.5 mm

  Anther number

  3

  Awn on glume

  the glume has no awn

  Bristles below spikelets

  no

  Floret lower bract texture

  the lemma is hard and firm

  Floret number

  1

  Floret types within spikelet

  all the florets within a spikelet are similar

  Glume awn length

  0 mm

  Glume relative length

  • neither glume is quite as long as all of the florets
  • one or both glumes are as long or longer than all of the florets

  Glume veins

  • 5
  • 7 or more

  Glumes per spikelet

  2

  Inflorescence arrangement

  the spikelets are uniform

  Inflorescence axis orientation

  the inflorescence axis is straight

  Inflorescence branch length

  3–9.5 cm

  Inflorescence branches

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

  Inflorescence branches coming off the lowest stem node

  1–2

  Inflorescence crowding

  the panicle is somewhat to very spread out, with clearly-evident branches

  Inflorescence length

  120–250 mm

  Inflorescence type (general)

  the spikelets are borne on stalks or on branches

  Inflorescence type (specific)

  the inflorescence is branched, and the branches do NOT both grow from the same side of the plant AND look like spikes

  Inforescence position

  the spikelets are mainly carried at the end of the stem

  Lemma awn base

  the awn is attached right at the tip of the lemma

  Lemma awn coiled

  the lemma awn is straight or twisted, but not coiled one half turn

  Lemma awn length

  10–25 mm

  Lemma awn number

  the lemma has one awn on it

  Lemma awn orientation

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

  Lemma base length

  0.3–0.6 mm

  Lemma cross-section

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

  Lemma hairs

  • the lemma has fine hairs between the veins
  • the lemma is hairless between the veins

  Lemma keel hairs

  NA

  Lemma marginal vein hairs

  • the marginal vein of the lemma has fine hairs on it
  • the marginal vein of the lemma is hairless

  Lemma surface

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

  Lemma tip

  the lemma tip is a simple point, with or without an awn (long narrow extension ending in a point)

  Lemma tip shape

  the lemma tip tapers to a narrow point (it may or may not also have an awn or teeth at the tip)

  Lemma vein number

  • 3
  • 5
  • 7 or more

  Lower glume length

  6–8 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

  Palea relative length

  palea is one half to fully as long as lemma

  Reproductive system

  all the flowers on the plant have both carpels and stamens (synoecious)

  Spikelet axis tip

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

  Spikelet disintegration

  the spikelet breaks off above the glumes, so that after the florets fall off, the glumes remain

  Spikelet length

  6–7.5 mm

  Spikelet number per node

  Up to 0

  Spikelet pedicel

  the spikelets have pedicels

  Spikelet position

  the spikelets emerge mainly from the upper halves of the inflorescence branches

  Spikelet shape

  • the spikelets are elliptic (widest in the middle, tapering to the ends) in profile
  • the spikelets are lanceolate (lance-shaped, widest below the middle and tapering narrowly to the ends) in profile
  • the spikelets are oblanceolate (lance-shaped, but with the widest point above the middle) in profile

  Spikelets per panicle branch

  2–5

  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

  6–8 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

• Fruits or seeds

  Seed length

  5–6 mm

• Growth form

  Lifespan

  the plant lives more than two years

  Rhizomes

  yes

  Roots

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

• Leaves

  Leaf auricles

  the leaves do not have auricles

  Leaf basal lobe hairy

  NA

  Leaf blade cross-section

  the leaf blade is clearly folded or rolled inwards

  Leaf blade hairs

  • the leaf blade is hairless, but it may have tiny prickles that give it a sand-papery feel
  • the leaf blade is hairy

  Leaf blade length

  10–27 cm

  Leaf blade texture

  • the leaf blade is rough and sandpapery
  • the leaf blade is smooth, or it may have soft hairs

  Leaf blade width

  8–15 mm

  Leaf ligule length

  0–0.7 mm

  Leaf ligule type

  • the leaf ligule is absent
  • 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 hairs

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

  Orientation of topmost leaf

  the flag leaf is held upright, or at less than a 45 degree angle out from the stem

• Place

  Habitat

  terrestrial

  New England state

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

  Specific habitat

  • forests
  • ridges or ledges

• Stem, shoot, branch

  Plant height

  48–80 cm

  Roots at lower stem nodes

  no

  Stem hairs

  • the stem has hairs on it
  • the stem is nearly to completely hairless

  Stem node number

  1–6

  Stem orientation

  the stems are upright

  Stem spacing

  the stems grow close together in compact clusters or tufts

Wetland status

Not classified

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae